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post #1 of 35 Old 02-19-2020, 02:48 AM - Thread Starter
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Question how to calculate for per hour watt consumtion?

Pro diy subs powered with a pro amp? Will power consumtion depend on source material if it is bass heavy?

I am trying to calculate power consumption for my new house and propossed home theater design since I will be installing solar panels and I want to install enough to be 100% independent from the power company.
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post #2 of 35 Old 02-19-2020, 06:48 AM
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Sound system power consumption will vary widely depending on the material being played. The best way to do it is to get an watt/hour meter & play many hours of the kind of stuff you'll be listening to & then calculate the per hour consumption from that.

edit: I should add that using class D amplifiers will greatly reduce consumption over class AB.
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post #3 of 35 Old 02-19-2020, 07:28 AM
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Refer to your other thread:
https://www.avsforum.com/forum/91-au...-per-hour.html



If you can’t explain it simply, you don’t understand it well enough – Albert Einstein
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post #4 of 35 Old 02-19-2020, 09:39 AM
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Quote:
Originally Posted by carlobenavidesahavia View Post
Pro diy subs powered with a pro amp? Will power consumtion depend on source material if it is bass heavy?

I am trying to calculate power consumption for my new house and propossed home theater design since I will be installing solar panels and I want to install enough to be 100% independent from the power company.
Having designed and installed a large (10kW, 1600 usable AH 48v nominal system), please understand that solar is simply NOT cost effective! The problem is storage, pure and simple. The electricity we buy from the power company is quite cheap for what it is. If one is building a home that will require 50-70k to run power into it (and some remote places do) it may well work.

The way to look at levels is to get a "Kill-a-watt" or newer competitor. You can plug in the appliance or whatever and it will keep track of usage for however long you choose to look. For example, I collected data for 14d on a basement dehumidifier in the middle of the summer. Realistically you aren't going to use THAT much power as you are only cranking heavy power for some milliseconds here and there. That's how these amps deliver power levels that are completely inconsistent with the wiring.

"Renewable energy" has the biggest problem of only being available SOMETIMES. So sufficient short term storage (batteries) and longer term (generator) is a necessity. Now, if I happened to own a property that had its own natural gas well... I could design an awesome setup! Only limited battery capacity needed, use the generator frequently.

BTW, there is always this promise of new battery technology but it is slow in coming. You and I don't have access to the GOOD Li batteries, the car companies are taking all of the production. FLA is workable, but lifespan is 7-10yrs under good conditions. New battery bank costs close to what the electric bill would have run!
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post #5 of 35 Old 02-19-2020, 09:47 AM
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Quote:
Originally Posted by frankwp View Post
edit: I should add that using class D amplifiers will greatly reduce consumption over class AB.

Though not as much as you'd think, unless listening at high levels for prolonged periods.

Because from what I've seen, the idle power consumption of class D is roughly 1/4 less than class AB.

Noah
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post #6 of 35 Old 02-19-2020, 09:57 AM
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Quote:
Originally Posted by MTBDOC View Post
"Renewable energy" has the biggest problem of only being available SOMETIMES. So sufficient short term storage (batteries) and longer term (generator) is a necessity. Now, if I happened to own a property that had its own natural gas well... I could design an awesome setup! Only limited battery capacity needed, use the generator frequently.

BTW, there is always this promise of new battery technology but it is slow in coming. You and I don't have access to the GOOD Li batteries, the car companies are taking all of the production. FLA is workable, but lifespan is 7-10yrs under good conditions. New battery bank costs close to what the electric bill would have run!
Outside of the cost of the batteries themselves, powering and using the batteries is also expensive in itself. Even good batteries aren't 100% efficient, and that cost adds up. I've seen a lot of studies at the residential level with some disappointing results in terms of battery storage usage =(

I think we're diving off topic a good bit, but wanted to mention it, regardless.
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post #7 of 35 Old 02-19-2020, 02:32 PM - Thread Starter
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I am getting a 20kw hybrid system with 240ah 12v batteries 32 pieces which can power me for the whole day. I live in the Philippines we have the most expensive electricity in the world but since I live in the Philippines I can order the system from China without the 30% tax donald trump put on you guys. The whole system will just cost 15k-18k dollars. with my current electricy usage off of the bill which is 1100WHR per month to 1700WHR I will recoupe my investment in 4 years. Plus the province where my fiancee lives has power outages once in awhile.

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Having designed and installed a large (10kW, 1600 usable AH 48v nominal system), please understand that solar is simply NOT cost effective! The problem is storage, pure and simple. The electricity we buy from the power company is quite cheap for what it is. If one is building a home that will require 50-70k to run power into it (and some remote places do) it may well work.

The way to look at levels is to get a "Kill-a-watt" or newer competitor. You can plug in the appliance or whatever and it will keep track of usage for however long you choose to look. For example, I collected data for 14d on a basement dehumidifier in the middle of the summer. Realistically you aren't going to use THAT much power as you are only cranking heavy power for some milliseconds here and there. That's how these amps deliver power levels that are completely inconsistent with the wiring.

"Renewable energy" has the biggest problem of only being available SOMETIMES. So sufficient short term storage (batteries) and longer term (generator) is a necessity. Now, if I happened to own a property that had its own natural gas well... I could design an awesome setup! Only limited battery capacity needed, use the generator frequently.

BTW, there is always this promise of new battery technology but it is slow in coming. You and I don't have access to the GOOD Li batteries, the car companies are taking all of the production. FLA is workable, but lifespan is 7-10yrs under good conditions. New battery bank costs close to what the electric bill would have run!
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post #8 of 35 Old 02-19-2020, 03:46 PM
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Originally Posted by carlobenavidesahavia View Post
I am getting a 20kw hybrid system with 240ah 12v batteries 32 pieces which can power me for the whole day. I live in the Philippines we have the most expensive electricity in the world but since I live in the Philippines I can order the system from China without the 30% tax donald trump put on you guys. The whole system will just cost 15k-18k dollars. with my current electricy usage off of the bill which is 1100WHR per month to 1700WHR I will recoupe my investment in 4 years. Plus the province where my fiancee lives has power outages once in awhile.
You are making a HUGE mistake using small 12v batteries. While "series-parallel" works well in speakers, it is TERRIBLE for batteries. DON'T DO IT! I set up 24 2v cells, each weighs about 160# or so. What happens when you are parallel wiring small batteries is that once one STARTS to go bad, it will drag down the rest of the system and swallow up power. Go to www.solarpaneltalk.com (the best internet forum I have found on the subject over a number of years of studying this).

Solar panels themselves can be had quite reasonably, I bought mine for about $.60-.70/watt. But realize that your batteries are a far bigger expense. Your proposed battery bank is roughly comparable to what I have for mine, but you will be lucky to get 5 yrs out of that setup. 20kW of panels will FRY these batteries... You don't want to charge them higher than C/10, and so for your 1920 AH @ 48v nominal, that means around 200 amps. 200a x 55v charging is 11,000 watts. What you are talking about is 20000/55 = 363a charging rate, almost C/5. That will DESTROY your little deep cycle 12v batteries. Also: realize that charge controllers and inverters have a limited lifespan as well. They are electronic devices that will wear out!

I don't mean to be a downer, but I have been blessed by folks on this forum who know a LOT about designing & building subwoofers. Well, this is something that I know a lot about having 'done it all' for my place up in the mountains. The 'self-sufficiency bug' has great appeal, and solar does have some utility, but I think you will be quite disappointed at the performance of this system. Whoever designed it for you has done a TERRIBLE job. You have a mis-match between 20kW panels and your battery capacity. And again, your battery bank will be IMPOSSIBLE to keep healthy. Do you realize that you are talking about 32x6= 192 cells that you will be CONSTANTLY adding distilled water to? At that charge rate, you will boil the electrolyte out on virtually a daily basis! My cells are about 32" tall, roughly 6"x6" square. They can go weeks without needing electrolyte, especially as I have set the charging voltage (as well as float) a little lower than many folks so the batteries don't outgas much.

I do hope you will consider what I have shared, go over to SPT and get some input from folks there, and IF you are still going to do this: DON'T USE GOLF CART BATTERIES! Yes, it will cost more to get large cells so you only have one string in series, but they will last far longer. Spend more on your battery bank and less on the panels.

Also: I cannot imagine how you are able to buy charge controllers and inverter in that budget. Outback FM80 controllers (I run 3) run 6-700 each, 8kW inverter about $4000. I designed my own mounts, not using "solar panel mounting systems" which are way overpriced. But I spent 40k just in materials (including building the structure on which I mounted it). Something just doesn't sound right with what you have posted. I hope I am not offending, as that is not my intention. I am spending a lot of time typing this out in the hopes it will help you.

Finally: the best approach is to DECREASE energy consumption and make life easier on the system. LED lights, efficient HVAC (I went with very high SEER ductless minisplit heat pumps), etc.
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post #9 of 35 Old 02-19-2020, 06:07 PM
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You are generally safe to assume the idle-power is in the range of 100-200watts per amplifier, maybe double that figure if you plan on booming lots.

If you want specifics you'll have to plug it into one of those Kill-A-Watt meters, but just know that those are limited to like 12A RMS or whatever.

Your inverter will have to be able to provide an even-higher burst-figure, and calculating that will be difficult\impossible without some serious measurement gear, like a Fluke power analyzer (rentable for a day etc).
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post #10 of 35 Old 02-19-2020, 06:36 PM
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I basically have to agree with everything MTBDOC has said.

20kW with 240AH @ 12v is just so-wrong, that's only like 8 minutes of runtime at full power (at best), and that's like a 10C rate.
It needs to be a MUCH higher voltage, and potentially more AH too.

I too am building a solar equipped HT (just the low-power equipment though: lights, projector, tv, computers, bdplayer, DSP/DACs etc)

Even though my solar system is 100% DIY and only rated for 1kW RMS it's still ending up costing me like 7 grand (to do properly).
Not even the whole house, just the HT room!
Even at this power-level it is still a 24V system, and I'll still need like untold amounts of AH and potentially another 3kW of panels just to sustain this most-basic load.

EMP hardening will cost me an extra 2-3k per 1kW, and reduce the efficiency by about 10%. (A necessary-evil IMO.)

I didn't completely cheap-out on my inverter, and I'm going for top-shelf consumer-grade Li batteries (about ~$12 per AH and electrolyte-less).
Batteries are by-far the most expensive component (if you get the good ones that last / are worth buying.)

Car and RV batteries have horrible efficiencies and lifespans, you'd be lucky to get 5 years out of a car/rv battery when used in a off-grid install, maybe a few more years if it is only used for fallback-power rather than bill-reduction.
If you stick with cheap batteries, be prepared to replace 600lbs of lead... every 5 years, forever.

and as mentioned, you'll be buying thousands in distilled water to keep the cheap batteries topped. (You may want to run a solar powered distillery in-fact. )

I figure even after 10 years use, I'll likely never break-even on my solar.
But I'm not doing it to save money... If I never break-even I'm cool with that reality.

A single space heater can be 1.5kW rms easily.
An HVAC system will be probably closer to 3-5kW rms.
Clothes dryer, dishwasher, toaster, oven, microwave... it just keeps adding up, but luckily you don't run them all at once (and if you do, you'll fry your solar system.) It has to be sized based on the load, as you know. Both RMS and burst.

Anything with a motor in it draw lots of burst power (vacuum cleaner, blender, fans, pumps etc)

Before you switch to solar you'll want to replace every incandescent, CFL and tube-lamp with 100% LED.
You want your load to be as low-as-possible before you dive in.
Energy Star appliances through-out, instant water-heater, energy-recovery HVAC, geo-thermal / heat-pump.
Better / more insulation in your house; more air-tight etc.
Everything that you CAN do, BEFORE implementing solar. (That's how inefficient and non-cost-effective solar is.)

That said / knowing all that... FULL-STEAM ahead captain, the iceberg is awaiting for us to arrive!

Last edited by BassThatHz; 02-19-2020 at 08:19 PM.
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post #11 of 35 Old 02-19-2020, 06:57 PM
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Quote:
Originally Posted by BassThatHz View Post
Your inverter will have to be able to provide an even-higher burst-figure...

Don't the batteries supply burst needs?

Noah
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post #12 of 35 Old 02-19-2020, 07:14 PM
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Batteries don't like to be drained.
They like floating at around 90% full at-all-times.
[People that use their phones until it says 0% are absolutely killing them.]

Same for solar, you'll only get like 25-40% of the rated-AH out of the cheap batteries. (Doing more will kill them faster... as-in they'll last 12 months. LOL!)

That's why Li is popular for whole-house solar, instead of 500 charge cycles, you can get thousands. They charge faster, sustain longer, and are WAY smaller/lighter, and just overall last longer. They are more expensive though... but you'll break-even within 10 years not having to buy 1200lbs of lead and acid and distilled water etc etc.

No free lunch. You'll pay now or later...
(Just like a 0$ phone or 0% down, you'll pay double by the end of the contract. The house always wins in the end, by-design. )

As mentioned, you also have to factor in clouds & panel debris (and shading too!)
Being closer to the equator your winters are probably not horribly-dark/cold I'd imagine, much better sun angle too!

Being DC, cables losses can be rather large. Gotta factor that in too! It all adds up...
Solar ain't-cheap... it's gotta be the most inefficient/expensive "thing" a person can buy!

Solar panels are like 23% efficient, like a 80% loss... before the first electron even moves anywhere!
Like 90% of the total-sunpower is lost in such a DC-to-AC system (yet surprisingly still produces multi-kW's...)
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post #13 of 35 Old 02-19-2020, 07:20 PM
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Originally Posted by noah katz View Post
Don't the batteries supply burst needs?
No.
The inverter will be more-limited than any known bank of battery-types, most banks can supply a burst of a few thousand amps. The inverter... not so much. (Also the wiring becomes a problem, because: low-voltage DC!)

The system is only as strong as the weakest link. (As per normal.)

I don't even know of a 12V 20kW inverter. All the ones I saw were 48V (or more).

Mine does 6kW rms and 18kW burst split-phase @ 240V, and is 24VDC based. Cost me a little over $1000.
That was sufficient for my project. I only need about 800w rms from it (not powering whole-house with it though.)

Last edited by BassThatHz; 02-19-2020 at 07:30 PM.
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post #14 of 35 Old 02-19-2020, 08:01 PM
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how to calculate for per hour watt consumtion?

MTBDOC and BTH have it pretty well covered.

Just to emphasize the battery needs, a quick pic:

Taken during the aforementioned battery change-out. One of two batteries. Those batteries lasted right at 10 years, and were below 70% capacity. They required monthly fills with distilled water.
Batteries controlled and maintained by outback charge controller, 48v IIRC.

They were replaced with sealed AGM’s, going on 4 years maintenance free.

That is a very small whole-building system with low storage capacity. Designed to maintain overnight/ very low use during multiple cloudy days.
Grid-feed with interconnected sine-wave Trace inverters. Very old tech at this point, I have no idea where the industry is at now.

That system has been operating for 14 years, and is nowhere near paying for itself. I believe we calculated it at 30-40 years when it was assembled, assuming 10yr battery swaps and no other failures.

I have seen a system designed for full-load use off storage. It had 2 40ft shipping containers as battery banks.

Chris

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post #15 of 35 Old 02-19-2020, 08:30 PM
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Let me clear this up a little bit more. His plan of 32 batteries is likely to link them, 4 in series, 8 parallel strings, so he would be running 48v nominal. That is what I based the numbers on. As far as power, my Outback inverter runs two parallel units that can run in sync (one is operational and it brings the other one on if there is sufficient need). Now this will produce 8kw @ 120/240v until the batteries die. It can produce 16kw on the order of a minute or two IIRC. In other words, you are talking 50amp 240v running for 20 min without a hitch. So the issue of surge is NOT an issue. Considering that most folks (not BTHz who is running an outrageous amount of juice) are running perhaps an NU6000 or two, so no worries.

The problem is simply the long-term issue. Trust me, we aren't talking about a few hundred lbs of batteries. My battery bank weighted 4400# on the shipping pallet! It was made by GB Battery, a company who got into the business with batteries for diesel-electric trains. As they have moved into solar, they are using the same cells that they use for forklift batteries. These things can produce GOBS of power, take a full charge at night ... and stay operational for years. Far more than 500 cycles.

Lithium batteries show promise, but they are far too expensive, and as I said we can't get our hands on the good ones. The little battery pack Elon Musk wants to sell is ridiculously expensive for what it is. Now there are people buying large lithium banks from Chinese suppliers, actually in a way quite similar to the clone amps. Some have good results, others get garbage. The factories have been running wide open in China to make Li cells; it is the 2nd rate ones that the smaller vendors end up with. Not the EV companies. They MAY break even or be ahead cost-wise. Actually no one knows as there aren't systems that have been running like that for 10 years. But I have a battery bank that is still extremely healthy, very little cell-to-cell variance. It has been in place for 3.5 yrs. It will last 10 yrs easily I believe. Water? Yeah, at a buck a gallon it doesn't break the bank ... but one thought in the back of my mind (zombies and such!) is to set up a water distillery to run off of wood for topping off the batteries.

BTHz, I cannot honestly believe you got a sine wave inverter that produces 6kW steady state from 24v for $1000. Your remark about inverters being limited? NO! A real inverter (such as my Outback) has a pair of leads to each of the two inverters. 2/0 welding cable to the inverter, but out of it is simply 240v 50amp to a secondary 'main panel' I added. I can keep grid attachment for $25/month which I have done. For prolonged bad weather (most systems are sized for perhaps 3 days without needing the generator) AND to help the battery bank last longer (I have the limits set so the batteries won't get discharged very deep if I still have grid power).

Losses shouldn't be as high as you are suggesting. Yes, silicon panels are 20-something% efficient, but that is simply turning the actual sunlight to flowing electrons. From there, efficiency is actually quite good. Wiring panels in series to raise voltage decreases loss. DC voltage drop is a known quantity, so properly sized (and again, I used high grade welding cable, calculating voltage drop across the distance, etc) it is quite manageable. The inverter itself is 90-something% efficient (sorry, I knew this a couple of years ago). Now some folks think running DC appliances is smart ... but it isn't. They are WAY too expensive, and panels are relatively cheap! Just add more power & get a good inverter.

For example, there is a company making a mini-split ductless A/C designed to run mostly off solar panels. It still needs a small ac connection for the electronics, but the compressor & fan are dc. Looking at the efficiency of it for heating and cooling, the need for panels solely connected to it ... and comparing it to a Mitsubishi 12000BTU heat pump with a SEER of 28. It didn't make sense. Just like people buying dc refrigerators to run off solar. Does not compute!

This is an interesting subject, especially for those of us who like the idea of self-sufficiency. Even in the Philippines it does not make economic sense. IF/when we get a big jump in battery technology (MAYBE Li, but the jury isn't in on that yet, and cost/availability are an issue, as is Li extraction mining).


Finally: batteries can flow almost unlimited current ... until they heat up and explode! I know that guys have described breaking something off road, and welding using 2 12v batteries in series, using a coat hanger for welding rod. It does work. I learned about welding at 2v... just dropped a bolt when I was doing some connections, and in an INSTANT the bolt and washer were welded together. By the grace of God it didn't weld to the lead lug (yet!) and so I got it off. But a short across a lead acid battery can flow MASSIVE amperage for a brief period. Most likely the lead "ears" on the cells would melt first. But a fire/explosion would also be likely!!!
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post #16 of 35 Old 02-19-2020, 08:32 PM
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Quote:
Originally Posted by a77cj7 View Post
MTBDOC and BTH have it pretty well covered.

Just to emphasize the battery needs, a quick pic:

Taken during the aforementioned battery change-out. One of two batteries. Those batteries lasted right at 10 years, and were below 70% capacity. They required monthly fills with distilled water.
Batteries controlled and maintained by outback charge controller, 48v IIRC.

They were replaced with sealed AGM’s, going on 4 years maintenance free.

That is a very small whole-building system with low storage capacity. Designed to maintain overnight/ very low use during multiple cloudy days.
Grid-feed with interconnected sine-wave Trace inverters. Very old tech at this point, I have no idea where the industry is at now.

That system has been operating for 14 years, and is nowhere near paying for itself. I believe we calculated it at 30-40 years when it was assembled, assuming 10yr battery swaps and no other failures.

I have seen a system designed for full-load use off storage. It had 2 40ft shipping containers as battery banks.

Chris
Nice pic! I actually bought a HF engine hoist to deal with my batteries! The forklift pack is all connected, but when they started selling for solar, they broke them into 6 cell trays. Steel case, weighs a bit over 1000# ... x 4.
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And the AGM batteries: they are more tolerant of higher charge current, but they don't last nearly as long as a good HEAVY deep cycle FLA. Most folks are used to car batteries which have very thin plates, made to dump a lot of current but to then get charged back up. The serious batteries (again, such as used for diesel electric trains, submarines, etc) have been around for decades, and they can be VERY long lived.

In the prepper world, people have wanted to bring back ANCIENT tech, such as an iron-nickel battery IIRC. They have incredibly poor charge efficiency, and very poor performance per lb of weight. Actually, what you need is what they did at Raccoon Mountain, outside of Chattanooga. Read up on it, this is absolutely FASCINATING as an approach to energy storage. TVA still uses it for surge requirements!
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post #18 of 35 Old 02-19-2020, 08:47 PM
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how to calculate for per hour watt consumtion?

Quote:
Originally Posted by MTBDOC View Post
Nice pic! I actually bought a HF engine hoist to deal with my batteries! The forklift pack is all connected, but when they started selling for solar, they broke them into 6 cell trays. Steel case, weighs a bit over 1000# ... x 4.


Exactly what that is. Only two in this setup as mentioned, low storage capacity.

Swapped to AGM primarily for maintenance concerns. Also lost one degassing fan AND indicator at same time, so partial safety issue indoors. Second fan was still running.
Agreed on less life than properly maintained FLA.

EDIT: The engine hoist is for engines. It took SIGNIFICANT cleaning/degreasing to make it carpet-ready.

Chris

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post #19 of 35 Old 02-19-2020, 09:04 PM - Thread Starter
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No no offense taken at all thank you for the advice and heads up. I would've been going into something really expensive ignorantly. What type of battery would you recommend? I will join forums as well to help in designing the system. Those batteries are gel type here is the entire list of the qoute from the chinese company.

14KW on off grid hybrid system Model
42pcs 335W Mono Solar Panel M72-335
32pcs 12V250AH Gel Battery GJ12-250
24pcs 5KW 1phase on off grid hybrid Inverter 4pcs infinisolar 5KW Plus
10.5sets Solar Panel Mounting SPM15

Mono Solar Panel 335W ITEM NO. M72-335
Maximum Power at ST(Pmax)W 335WP Maximum Power Voltage(Vmp)V 38.2 Maximum Power Current(Imp)A8.77A Open Circuit Voltage(Voc)V 45.6V Short Circuit Current(Isc)A 19.35A Cell Efficiency(%) 18.34% Size of Module (mm) 1956*990*40
$85 42pcs $3,570

12V250AH Gel Battery Item: FMJ12-250 Maintenance-free Silver-coated copper terminals, brass insert Terminals and lead terminals improve theelectric conductivity Life Span: 8-10years Size :520*240*216mm
$205 32pcs $6,560

5KW On Off Grid Solar Inverter Model : Infinisolar PLUS 5KW
Max Solar Invput power : 10000W Max PV input voltage 900V MPPT volatge range :250V ~ 850VDC Grid output 230V single phase 21A 60HZ Battery voltage 48V Efficiency :91% RS232/USB communication port , parallel connect Size :204*460*600mm Weight:29kg Germeny standar VDE-0126 Grid tie with battery back up , will export the excess power to the grid 4pcs parallel working to 20KW output
$1,650 4pcs $6,600

Mounting structure Installation site : tile roor /Tin Roof pitched ( optional)
Material:Al6005-T5 Extruded Aluminum Section High Class Anodized Aluminum one set brackets can mount 4pcs solar panels
Wind Load :up to 130mph (60m/s) Snow Load : up to 30psf (1.4kN/m2)
$105 10.5sets $1,102

Connection cables 4mm Solar panel connection cables : 250meter
8mm Battery connection cables :50meter 8mm Electric cables :50meter
$400 1set $400

Connector solar cables MC4 ,battery cables connector $2 20sets $40
Battery DC circuit breaker 2P 500V100A

DC For solar input , battery input
$30 2pcs $60

AC circuit breaker
220V 50A 2P $10 2pcs $20
Total FOB Foshan China Price $18,352.0

Remark: 1. Price terms: FOB Foshan China Price 2. Payment: T/T 30% deposit in advance , balance before shipment 3. Warranty: solar panel 25 years,deep cycle battery, controller, inverter 2 years, 4. Delivery time: would be 15days from receipt of deposit.



Quote:
Originally Posted by MTBDOC View Post
You are making a HUGE mistake using small 12v batteries. While "series-parallel" works well in speakers, it is TERRIBLE for batteries. DON'T DO IT! I set up 24 2v cells, each weighs about 160# or so. What happens when you are parallel wiring small batteries is that once one STARTS to go bad, it will drag down the rest of the system and swallow up power. Go to www.solarpaneltalk.com (the best internet forum I have found on the subject over a number of years of studying this).

Solar panels themselves can be had quite reasonably, I bought mine for about $.60-.70/watt. But realize that your batteries are a far bigger expense. Your proposed battery bank is roughly comparable to what I have for mine, but you will be lucky to get 5 yrs out of that setup. 20kW of panels will FRY these batteries... You don't want to charge them higher than C/10, and so for your 1920 AH @ 48v nominal, that means around 200 amps. 200a x 55v charging is 11,000 watts. What you are talking about is 20000/55 = 363a charging rate, almost C/5. That will DESTROY your little deep cycle 12v batteries. Also: realize that charge controllers and inverters have a limited lifespan as well. They are electronic devices that will wear out!

I don't mean to be a downer, but I have been blessed by folks on this forum who know a LOT about designing & building subwoofers. Well, this is something that I know a lot about having 'done it all' for my place up in the mountains. The 'self-sufficiency bug' has great appeal, and solar does have some utility, but I think you will be quite disappointed at the performance of this system. Whoever designed it for you has done a TERRIBLE job. You have a mis-match between 20kW panels and your battery capacity. And again, your battery bank will be IMPOSSIBLE to keep healthy. Do you realize that you are talking about 32x6= 192 cells that you will be CONSTANTLY adding distilled water to? At that charge rate, you will boil the electrolyte out on virtually a daily basis! My cells are about 32" tall, roughly 6"x6" square. They can go weeks without needing electrolyte, especially as I have set the charging voltage (as well as float) a little lower than many folks so the batteries don't outgas much.

I do hope you will consider what I have shared, go over to SPT and get some input from folks there, and IF you are still going to do this: DON'T USE GOLF CART BATTERIES! Yes, it will cost more to get large cells so you only have one string in series, but they will last far longer. Spend more on your battery bank and less on the panels.

Also: I cannot imagine how you are able to buy charge controllers and inverter in that budget. Outback FM80 controllers (I run 3) run 6-700 each, 8kW inverter about $4000. I designed my own mounts, not using "solar panel mounting systems" which are way overpriced. But I spent 40k just in materials (including building the structure on which I mounted it). Something just doesn't sound right with what you have posted. I hope I am not offending, as that is not my intention. I am spending a lot of time typing this out in the hopes it will help you.

Finally: the best approach is to DECREASE energy consumption and make life easier on the system. LED lights, efficient HVAC (I went with very high SEER ductless minisplit heat pumps), etc.
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Many thanks for the advice I am actually designing a new house so everything will have smart components and LED all the air conditioning will be inverter type and the whole house will be concrete. Please refer to the post of items the chinese cimpany qouted me. My daily wattage is at 60KHW per day over estimated as of now in my old townhouse it is at 35KWH but I want the system to completely run my entire power. I have a lot of high wattage kitchen appliances like the Ninja foodi, Sous Vide, Microwave, Electric Stove and Electric smoker. 2 2.5hp inverter air conditionaires. 1 will be running the whole day since it is hot in the Philippines the other one will be in the Home theater. 3 1.5hp inverter airconditionaires in other rooms. Washing machine and dryer. The home theater will have a 7x200 watt power amp. 2 21 inch lavoce sans in devastators. 2 21 inch Lavoce Sans in Full marties run by a Sinbosen FP22000Q 4 x 2500w at 8 ohms. Epson 5040ub projector. NAD 758 v3 and planning to buy a Hyundai Sona EV.


Quote:
Originally Posted by BassThatHz View Post
I basically have to agree with everything MTBDOC has said.

20kW with 240AH @ 12v is just so-wrong, that's only like 8 minutes of runtime at full power (at best), and that's like a 10C rate.
It needs to be a MUCH higher voltage, and potentially more AH too.

I too am building a solar equipped HT (just the low-power equipment though: lights, projector, tv, computers, bdplayer, DSP/DACs etc)

Even though my solar system is 100% DIY and only rated for 1kW RMS it's still ending up costing me like 7 grand (to do properly).
Not even the whole house, just the HT room!
Even at this power-level it is still a 24V system, and I'll still need like untold amounts of AH and potentially another 3kW of panels just to sustain this most-basic load.

EMP hardening will cost me an extra 2-3k per 1kW, and reduce the efficiency by about 10%. (A necessary-evil IMO.)

I didn't completely cheap-out on my inverter, and I'm going for top-shelf consumer-grade Li batteries (about ~$12 per AH and electrolyte-less).
Batteries are by-far the most expensive component (if you get the good ones that last / are worth buying.)

Car and RV batteries have horrible efficiencies and lifespans, you'd be lucky to get 5 years out of a car/rv battery when used in a off-grid install, maybe a few more years if it is only used for fallback-power rather than bill-reduction.
If you stick with cheap batteries, be prepared to replace 600lbs of lead... every 5 years, forever.

and as mentioned, you'll be buying thousands in distilled water to keep the cheap batteries topped. (You may want to run a solar powered distillery in-fact. )

I figure even after 10 years use, I'll likely never break-even on my solar.
But I'm not doing it to save money... If I never break-even I'm cool with that reality.

A single space heater can be 1.5kW rms easily.
An HVAC system will be probably closer to 3-5kW rms.
Clothes dryer, dishwasher, toaster, oven, microwave... it just keeps adding up, but luckily you don't run them all at once (and if you do, you'll fry your solar system.) It has to be sized based on the load, as you know. Both RMS and burst.

Anything with a motor in it draw lots of burst power (vacuum cleaner, blender, fans, pumps etc)

Before you switch to solar you'll want to replace every incandescent, CFL and tube-lamp with 100% LED.
You want your load to be as low-as-possible before you dive in.
Energy Star appliances through-out, instant water-heater, energy-recovery HVAC, geo-thermal / heat-pump.
Better / more insulation in your house; more air-tight etc.
Everything that you CAN do, BEFORE implementing solar. (That's how inefficient and non-cost-effective solar is.)

That said / knowing all that... FULL-STEAM ahead captain, the iceberg is awaiting for us to arrive!
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Here's another qoute the batteries look better. Should I change inverter to 3 pieces?

Solar Panel
Power: 340W
Voltage: 36V
Weight:26KG
Size:1956*992*40mm
44 $74.80 US$3,291.20

PV Combiner Box 4 input 4 output
(Switches,Breaker,SPD) 1 $300.00 US$300.00

2 pices Hybrid Inverter Rated power output: 7.6kw
2 $1,617.65 US$3,235.29

Solar Battery with cable 2V 1500AH 20 $308.82 US$6,176.47
6 PV Cable PV 4mm2 400 $1.50 US$600.00

7 MC4 Connector Rated current: 30A
Rated voltage: 1000VDC
30 $1.00 US$30.00

8 Mounting System
(including all parts)
Roof/Ground whole set for 32pcs solar module $1,645.60 US$1,645.60

Total EXW Cost US$15,278.56

Quote:
Originally Posted by MTBDOC View Post
Let me clear this up a little bit more. His plan of 32 batteries is likely to link them, 4 in series, 8 parallel strings, so he would be running 48v nominal. That is what I based the numbers on. As far as power, my Outback inverter runs two parallel units that can run in sync (one is operational and it brings the other one on if there is sufficient need). Now this will produce 8kw @ 120/240v until the batteries die. It can produce 16kw on the order of a minute or two IIRC. In other words, you are talking 50amp 240v running for 20 min without a hitch. So the issue of surge is NOT an issue. Considering that most folks (not BTHz who is running an outrageous amount of juice) are running perhaps an NU6000 or two, so no worries.

The problem is simply the long-term issue. Trust me, we aren't talking about a few hundred lbs of batteries. My battery bank weighted 4400# on the shipping pallet! It was made by GB Battery, a company who got into the business with batteries for diesel-electric trains. As they have moved into solar, they are using the same cells that they use for forklift batteries. These things can produce GOBS of power, take a full charge at night ... and stay operational for years. Far more than 500 cycles.

Lithium batteries show promise, but they are far too expensive, and as I said we can't get our hands on the good ones. The little battery pack Elon Musk wants to sell is ridiculously expensive for what it is. Now there are people buying large lithium banks from Chinese suppliers, actually in a way quite similar to the clone amps. Some have good results, others get garbage. The factories have been running wide open in China to make Li cells; it is the 2nd rate ones that the smaller vendors end up with. Not the EV companies. They MAY break even or be ahead cost-wise. Actually no one knows as there aren't systems that have been running like that for 10 years. But I have a battery bank that is still extremely healthy, very little cell-to-cell variance. It has been in place for 3.5 yrs. It will last 10 yrs easily I believe. Water? Yeah, at a buck a gallon it doesn't break the bank ... but one thought in the back of my mind (zombies and such!) is to set up a water distillery to run off of wood for topping off the batteries.

BTHz, I cannot honestly believe you got a sine wave inverter that produces 6kW steady state from 24v for $1000. Your remark about inverters being limited? NO! A real inverter (such as my Outback) has a pair of leads to each of the two inverters. 2/0 welding cable to the inverter, but out of it is simply 240v 50amp to a secondary 'main panel' I added. I can keep grid attachment for $25/month which I have done. For prolonged bad weather (most systems are sized for perhaps 3 days without needing the generator) AND to help the battery bank last longer (I have the limits set so the batteries won't get discharged very deep if I still have grid power).

Losses shouldn't be as high as you are suggesting. Yes, silicon panels are 20-something% efficient, but that is simply turning the actual sunlight to flowing electrons. From there, efficiency is actually quite good. Wiring panels in series to raise voltage decreases loss. DC voltage drop is a known quantity, so properly sized (and again, I used high grade welding cable, calculating voltage drop across the distance, etc) it is quite manageable. The inverter itself is 90-something% efficient (sorry, I knew this a couple of years ago). Now some folks think running DC appliances is smart ... but it isn't. They are WAY too expensive, and panels are relatively cheap! Just add more power & get a good inverter.

For example, there is a company making a mini-split ductless A/C designed to run mostly off solar panels. It still needs a small ac connection for the electronics, but the compressor & fan are dc. Looking at the efficiency of it for heating and cooling, the need for panels solely connected to it ... and comparing it to a Mitsubishi 12000BTU heat pump with a SEER of 28. It didn't make sense. Just like people buying dc refrigerators to run off solar. Does not compute!

This is an interesting subject, especially for those of us who like the idea of self-sufficiency. Even in the Philippines it does not make economic sense. IF/when we get a big jump in battery technology (MAYBE Li, but the jury isn't in on that yet, and cost/availability are an issue, as is Li extraction mining).


Finally: batteries can flow almost unlimited current ... until they heat up and explode! I know that guys have described breaking something off road, and welding using 2 12v batteries in series, using a coat hanger for welding rod. It does work. I learned about welding at 2v... just dropped a bolt when I was doing some connections, and in an INSTANT the bolt and washer were welded together. By the grace of God it didn't weld to the lead lug (yet!) and so I got it off. But a short across a lead acid battery can flow MASSIVE amperage for a brief period. Most likely the lead "ears" on the cells would melt first. But a fire/explosion would also be likely!!!
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What would the best configuration for 60-70kwh batteries be also I found this supplier for cheap lithium phosphate batteries they have many different configurations.

https://www.alibaba.com/product-deta...6de51eo6VK&s=p


Quote:
Originally Posted by MTBDOC View Post
You are making a HUGE mistake using small 12v batteries. While "series-parallel" works well in speakers, it is TERRIBLE for batteries. DON'T DO IT! I set up 24 2v cells, each weighs about 160# or so. What happens when you are parallel wiring small batteries is that once one STARTS to go bad, it will drag down the rest of the system and swallow up power. Go to www.solarpaneltalk.com (the best internet forum I have found on the subject over a number of years of studying this).

Solar panels themselves can be had quite reasonably, I bought mine for about $.60-.70/watt. But realize that your batteries are a far bigger expense. Your proposed battery bank is roughly comparable to what I have for mine, but you will be lucky to get 5 yrs out of that setup. 20kW of panels will FRY these batteries... You don't want to charge them higher than C/10, and so for your 1920 AH @ 48v nominal, that means around 200 amps. 200a x 55v charging is 11,000 watts. What you are talking about is 20000/55 = 363a charging rate, almost C/5. That will DESTROY your little deep cycle 12v batteries. Also: realize that charge controllers and inverters have a limited lifespan as well. They are electronic devices that will wear out!

I don't mean to be a downer, but I have been blessed by folks on this forum who know a LOT about designing & building subwoofers. Well, this is something that I know a lot about having 'done it all' for my place up in the mountains. The 'self-sufficiency bug' has great appeal, and solar does have some utility, but I think you will be quite disappointed at the performance of this system. Whoever designed it for you has done a TERRIBLE job. You have a mis-match between 20kW panels and your battery capacity. And again, your battery bank will be IMPOSSIBLE to keep healthy. Do you realize that you are talking about 32x6= 192 cells that you will be CONSTANTLY adding distilled water to? At that charge rate, you will boil the electrolyte out on virtually a daily basis! My cells are about 32" tall, roughly 6"x6" square. They can go weeks without needing electrolyte, especially as I have set the charging voltage (as well as float) a little lower than many folks so the batteries don't outgas much.

I do hope you will consider what I have shared, go over to SPT and get some input from folks there, and IF you are still going to do this: DON'T USE GOLF CART BATTERIES! Yes, it will cost more to get large cells so you only have one string in series, but they will last far longer. Spend more on your battery bank and less on the panels.

Also: I cannot imagine how you are able to buy charge controllers and inverter in that budget. Outback FM80 controllers (I run 3) run 6-700 each, 8kW inverter about $4000. I designed my own mounts, not using "solar panel mounting systems" which are way overpriced. But I spent 40k just in materials (including building the structure on which I mounted it). Something just doesn't sound right with what you have posted. I hope I am not offending, as that is not my intention. I am spending a lot of time typing this out in the hopes it will help you.

Finally: the best approach is to DECREASE energy consumption and make life easier on the system. LED lights, efficient HVAC (I went with very high SEER ductless minisplit heat pumps), etc.
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You have no charge controllers listed! Basically you go from panels => combiner box, which is like a box of circuit breakers, only backwards in that it takes multiple circuits of panels and combines them back into fewer circuits => charge controllers; this is the 'battery charger' and is programmed to meet the specific needs of the batteries as far as charging voltage, current, and time => battery bank => inverter

You don't need 20kW of inverters, you should NEVER be running that much power out of your solar setup! I enjoy watching the Mitsubishi minisplit kick on and only use a few hundred watts while dumping LOTS of cold, dehumidified air. The big circuits I set up were the swimming pool pump, a/c, dehumidifier, and refrigerator. Doesn't take nearly the capacity I have.

Batteries: the 2v 1500ah cells is more like mine. Is that total capacity (and you never want to use more than 80% of total) or usable? Mine are rated at 1600 usable. One troubling thing is that it lists 20 cells, not 24 which is what you need for a 48v system. Now these cells are around 2.2v, but the battery isn't actually 48v but 52-53v. You need 48v nominal. The pricing looks fairly comparable to what I paid for US manufactured cells INCLUDING freight. Coming from China, those prices appear very high.

LiFeP batteries are the future for this, I believe. The question is this: how good are these batteries being sold on Alibaba? There is just NO WAY TO KNOW! You will need charge controllers set up that can do the proper charge cycle for these batteries.

PLEASE SLOW DOWN! You are WAY ahead of yourself worrying about stuff on THIS FORUM (that is amplifier power demands and usage). You need to learn a great deal more.

First: do some engineering calculations based on actual heat load on the house. How much A/C will you need during the peak hot season? What are the other loads? Yes, taking HT into account is fine, but you are talking about a couple of hours several days per week most likely. This should be a fairly modest energy load. Look at cooling (the minisplit heat pumps will work well in your climate; they do use a lot more electricity in the winter, BUT your solar panels are far more efficient in cold than when hot.

Taking into account cold temps in the mountains made me complete change my design. I was planning on putting 3 panels together in series, but the charge controllers (CCs) are limited to 150v dc. Now the nominal specs on the panels are similar to yours, showing 40-something volts open circuit. HOWEVER: there is a temperature correction factor! When I did the math and looked at 0*F temps, the voltage was about 50 and so it could exceed 150v to the CC. Therefore I had to back it down to 2 panels per string ... which added a third circuit of HEAVY COPPER CABLE from the array, an additional combiner box & breakers, and a 3rd CC. Now you won't have that issue in the winter, I am sure. So you can run 3 panels/string. But this is the sort of thing you need to know before you just start throwing parts together.

And get rid of the idea of an electric vehicle! That would be STUPID as it is an additional load, HIGH demand, intermittent on your solar system. Yes, IF you can charge it during the daytime when you have excess production ... but most likely you will want to USE the car in the daytime! Trust me, just run on gasoline! You see, I run the pool pump & A/C on solar ... and it has the greatest demand WHEN THE SUN IS SHINING!

Okay, I really can't spend any more time on this. Go over to solarpaneltalk, read a lot, ask questions. Basically they will say compute your daily needs, figure out how many kWh that you would need for 3 days of no sunshine, size your system so that you aren't using more than about 60% capacity to do that. Then look at what your insolation averages are in your area. Look at the best charging rate for the batteries you propose to you. Size it that way.

I didn't do this. I took advantage of a clearance from a HUGE seller in Miami (both retail and wholesale) and bought a pallet. Later I decided to buy another pallet (I've used 36 panels, had one broken in a storm during construction when I was neglectful in fully securing panels on one end; one flipped over and the corner smashed another one!; and still have 11 leftover). By the way, the leftovers I have considered for various uses. One possibility is orienting some panels east and west, rather than south, which takes advantage of early morning and late afternoon sun. It gives more 'off peak' charging, which allows a slower, more gentle charge. Anyway, I bought the panels, then started sizing from there. I have more capacity than I need, to be honest. I still haven't shifted EVERYTHING over to the solar supply ... so I pay a few $/month along with the grid connection fee.

Out of curiosity, what is the rate you pay per kWh in your location? I still find it hard to believe you would be better off with solar. The 'sell back to the power company' isn't worth it, either.
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Quote:
Originally Posted by MTBDOC View Post
The 'sell back to the power company' isn't worth it, either.

Agreed on that one. The system I referenced does because that building is very intermittent-use. Also, it was the first one in the state, helped lay the groundwork for much larger-scale setups.

The power company pays far less per kW than they charge.

Chris
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The highest rates here is 10.50 to 11 pesos per kwh which is .21 to .22 US dollars I heard you guys pay half at .11 cents or below. So yeah the return on investment will come back in 4 years max....

Many thanks for your time I registered on that forum you sent me and clicked on the confirmation e-mail link they sent me but I still can't post or reply to any threads. Is there anything else I can do?

Quote:
Originally Posted by MTBDOC View Post
You have no charge controllers listed! Basically you go from panels => combiner box, which is like a box of circuit breakers, only backwards in that it takes multiple circuits of panels and combines them back into fewer circuits => charge controllers; this is the 'battery charger' and is programmed to meet the specific needs of the batteries as far as charging voltage, current, and time => battery bank => inverter

You don't need 20kW of inverters, you should NEVER be running that much power out of your solar setup! I enjoy watching the Mitsubishi minisplit kick on and only use a few hundred watts while dumping LOTS of cold, dehumidified air. The big circuits I set up were the swimming pool pump, a/c, dehumidifier, and refrigerator. Doesn't take nearly the capacity I have.

Batteries: the 2v 1500ah cells is more like mine. Is that total capacity (and you never want to use more than 80% of total) or usable? Mine are rated at 1600 usable. One troubling thing is that it lists 20 cells, not 24 which is what you need for a 48v system. Now these cells are around 2.2v, but the battery isn't actually 48v but 52-53v. You need 48v nominal. The pricing looks fairly comparable to what I paid for US manufactured cells INCLUDING freight. Coming from China, those prices appear very high.

LiFeP batteries are the future for this, I believe. The question is this: how good are these batteries being sold on Alibaba? There is just NO WAY TO KNOW! You will need charge controllers set up that can do the proper charge cycle for these batteries.

PLEASE SLOW DOWN! You are WAY ahead of yourself worrying about stuff on THIS FORUM (that is amplifier power demands and usage). You need to learn a great deal more.

First: do some engineering calculations based on actual heat load on the house. How much A/C will you need during the peak hot season? What are the other loads? Yes, taking HT into account is fine, but you are talking about a couple of hours several days per week most likely. This should be a fairly modest energy load. Look at cooling (the minisplit heat pumps will work well in your climate; they do use a lot more electricity in the winter, BUT your solar panels are far more efficient in cold than when hot.

Taking into account cold temps in the mountains made me complete change my design. I was planning on putting 3 panels together in series, but the charge controllers (CCs) are limited to 150v dc. Now the nominal specs on the panels are similar to yours, showing 40-something volts open circuit. HOWEVER: there is a temperature correction factor! When I did the math and looked at 0*F temps, the voltage was about 50 and so it could exceed 150v to the CC. Therefore I had to back it down to 2 panels per string ... which added a third circuit of HEAVY COPPER CABLE from the array, an additional combiner box & breakers, and a 3rd CC. Now you won't have that issue in the winter, I am sure. So you can run 3 panels/string. But this is the sort of thing you need to know before you just start throwing parts together.

And get rid of the idea of an electric vehicle! That would be STUPID as it is an additional load, HIGH demand, intermittent on your solar system. Yes, IF you can charge it during the daytime when you have excess production ... but most likely you will want to USE the car in the daytime! Trust me, just run on gasoline! You see, I run the pool pump & A/C on solar ... and it has the greatest demand WHEN THE SUN IS SHINING!

Okay, I really can't spend any more time on this. Go over to solarpaneltalk, read a lot, ask questions. Basically they will say compute your daily needs, figure out how many kWh that you would need for 3 days of no sunshine, size your system so that you aren't using more than about 60% capacity to do that. Then look at what your insolation averages are in your area. Look at the best charging rate for the batteries you propose to you. Size it that way.

I didn't do this. I took advantage of a clearance from a HUGE seller in Miami (both retail and wholesale) and bought a pallet. Later I decided to buy another pallet (I've used 36 panels, had one broken in a storm during construction when I was neglectful in fully securing panels on one end; one flipped over and the corner smashed another one!; and still have 11 leftover). By the way, the leftovers I have considered for various uses. One possibility is orienting some panels east and west, rather than south, which takes advantage of early morning and late afternoon sun. It gives more 'off peak' charging, which allows a slower, more gentle charge. Anyway, I bought the panels, then started sizing from there. I have more capacity than I need, to be honest. I still haven't shifted EVERYTHING over to the solar supply ... so I pay a few $/month along with the grid connection fee.

Out of curiosity, what is the rate you pay per kWh in your location? I still find it hard to believe you would be better off with solar. The 'sell back to the power company' isn't worth it, either.
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Forgot to say those rates I stated are normal rates since I am a heavy user 3 times the normal filipino household which consumes round 300-600 KWH per month they put multipliers on my bill as penalties. So yeah being a home theater and computer nerd here who is always at home and working out has a lot of drawbacks but great ROI if I have solar.... I own a business and just sign checks once a week so I am at home 95% of the time and put in more of my electrical consumption when the sky is bright.

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Originally Posted by MTBDOC View Post
You have no charge controllers listed! Basically you go from panels => combiner box, which is like a box of circuit breakers, only backwards in that it takes multiple circuits of panels and combines them back into fewer circuits => charge controllers; this is the 'battery charger' and is programmed to meet the specific needs of the batteries as far as charging voltage, current, and time => battery bank => inverter

You don't need 20kW of inverters, you should NEVER be running that much power out of your solar setup! I enjoy watching the Mitsubishi minisplit kick on and only use a few hundred watts while dumping LOTS of cold, dehumidified air. The big circuits I set up were the swimming pool pump, a/c, dehumidifier, and refrigerator. Doesn't take nearly the capacity I have.

Batteries: the 2v 1500ah cells is more like mine. Is that total capacity (and you never want to use more than 80% of total) or usable? Mine are rated at 1600 usable. One troubling thing is that it lists 20 cells, not 24 which is what you need for a 48v system. Now these cells are around 2.2v, but the battery isn't actually 48v but 52-53v. You need 48v nominal. The pricing looks fairly comparable to what I paid for US manufactured cells INCLUDING freight. Coming from China, those prices appear very high.

LiFeP batteries are the future for this, I believe. The question is this: how good are these batteries being sold on Alibaba? There is just NO WAY TO KNOW! You will need charge controllers set up that can do the proper charge cycle for these batteries.

PLEASE SLOW DOWN! You are WAY ahead of yourself worrying about stuff on THIS FORUM (that is amplifier power demands and usage). You need to learn a great deal more.

First: do some engineering calculations based on actual heat load on the house. How much A/C will you need during the peak hot season? What are the other loads? Yes, taking HT into account is fine, but you are talking about a couple of hours several days per week most likely. This should be a fairly modest energy load. Look at cooling (the minisplit heat pumps will work well in your climate; they do use a lot more electricity in the winter, BUT your solar panels are far more efficient in cold than when hot.

Taking into account cold temps in the mountains made me complete change my design. I was planning on putting 3 panels together in series, but the charge controllers (CCs) are limited to 150v dc. Now the nominal specs on the panels are similar to yours, showing 40-something volts open circuit. HOWEVER: there is a temperature correction factor! When I did the math and looked at 0*F temps, the voltage was about 50 and so it could exceed 150v to the CC. Therefore I had to back it down to 2 panels per string ... which added a third circuit of HEAVY COPPER CABLE from the array, an additional combiner box & breakers, and a 3rd CC. Now you won't have that issue in the winter, I am sure. So you can run 3 panels/string. But this is the sort of thing you need to know before you just start throwing parts together.

And get rid of the idea of an electric vehicle! That would be STUPID as it is an additional load, HIGH demand, intermittent on your solar system. Yes, IF you can charge it during the daytime when you have excess production ... but most likely you will want to USE the car in the daytime! Trust me, just run on gasoline! You see, I run the pool pump & A/C on solar ... and it has the greatest demand WHEN THE SUN IS SHINING!

Okay, I really can't spend any more time on this. Go over to solarpaneltalk, read a lot, ask questions. Basically they will say compute your daily needs, figure out how many kWh that you would need for 3 days of no sunshine, size your system so that you aren't using more than about 60% capacity to do that. Then look at what your insolation averages are in your area. Look at the best charging rate for the batteries you propose to you. Size it that way.

I didn't do this. I took advantage of a clearance from a HUGE seller in Miami (both retail and wholesale) and bought a pallet. Later I decided to buy another pallet (I've used 36 panels, had one broken in a storm during construction when I was neglectful in fully securing panels on one end; one flipped over and the corner smashed another one!; and still have 11 leftover). By the way, the leftovers I have considered for various uses. One possibility is orienting some panels east and west, rather than south, which takes advantage of early morning and late afternoon sun. It gives more 'off peak' charging, which allows a slower, more gentle charge. Anyway, I bought the panels, then started sizing from there. I have more capacity than I need, to be honest. I still haven't shifted EVERYTHING over to the solar supply ... so I pay a few $/month along with the grid connection fee.

Out of curiosity, what is the rate you pay per kWh in your location? I still find it hard to believe you would be better off with solar. The 'sell back to the power company' isn't worth it, either.
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post #27 of 35 Old 02-20-2020, 12:19 PM
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Think about this VERY carefully: the same energy saving things (such as LED lights, high efficiency minisplit heat pumps, good insulation & shading on west side of house, etc) are worth doing. But think about this: you are talking about a huge investment in money up front. That is capital tied up that cannot be used for anything else. That likely means debt. You are optimistically figuring a very short payback ... which is speculation. You are thinking this would be the BEST case. It could well be far more costly than you realize, and you have a great deal of expense not yet added in. Besides more equipment (such as the charge controllers) and HEAVY GAUGE WIRING, you are likely going to pay a lot of the installation itself.

Realize this: it takes a good bit of effort to monitor and maintain a solar system. Especially with FLA batteries, but as I have noted you are considering Li batteries that don't have the sort of track record to project lifespan, etc.

Now, let me ask you this: what will the power company pay you for solar production? It might be that they will pay a good 'peak rate' for supply in the sunny part of the day in summer, a time when everyone else needs MORE electricity. If they actually paid you as much as you pay them when you require electricity from them, then it might be cost effective. If you produce enough kW in the day and are selling it back to them, an r

I didn't grid tie as the rate that is paid out isn't enough to be worthwhile. It ALSO requires a full inspection before you can do that, and the NEC (national electrical code) has internal inconsistencies and many people end up with huge issues dealing with inspectors 'signing off' on their install. My situation is different as it is in a VERY rural location. No inspections necessary for construction and such, and I conceived of the property as a rural retreat. I enjoyed doing the project myself, spending about a year and a half building the structure and then doing the solar install.

Do you REALLY want to make such a commitment of capital and time? Just the fact that you were looking at a bank made of multiple small batteries means you don't know much. I mean this respectfully, not as an insult but just as an educated observation. I continue to make the effort to share my knowledge & experience as part of my goal to honor God in all that I do. I see a person in need (you!) and I have the ability to help... sometimes online forums become hostile but I truly want to be helpful for you.

Go to solarpaneltalk and do some reading on the off-grid subforum. Make a few small posts on other threads as you read. Maybe ask for clarification of some small issue. Once you get a feel for the place, then perhaps start a thread and lay out your proposal. There is one EXPERT (and he does have a great deal of expertise) who will tell you that you are an idiot, but others will be more supportive. But I suspect virtually everything I have written to you will be validated. Now I haven't been keeping up with that forum over the past 2-3 yrs, it may be that there are enough people with good experience to support the Chinese Li batteries, but it has been few and far between in the past.
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post #28 of 35 Old 02-20-2020, 01:07 PM - Thread Starter
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Thank you judging by your tone and talking about God it looks like you are a born again believer too. I used to be a pastor aside from the savings this is really prepping for what may happen around the corner. Matthew 7 and all. Yup I fell some things are about to happen and this would be an invesment if I break even or get an ROI that would be great if not and a war breaks out then I am prepared. On another note there is a whole day blackout in that area once a month so I want to have power for that day as well. I computed the loan as well which will go with my mortgage of the new house and the addition of it is well below my monthly electric bill. Also I am planning to put the new house on sale right away after building it with a free home theater, gym, and solar system. It a new area and development and most of the home in the price range I am going to sell it at which is double what I paid on construction and equipment will make out next house free. If it doesn't sell hey at least I got a solar powered house lol.

God bless brother. Thank you for the help

BTW I don't need heat pumps and stuff for winter the Philippines is located on the equator.

Quote:
Originally Posted by MTBDOC View Post
Think about this VERY carefully: the same energy saving things (such as LED lights, high efficiency minisplit heat pumps, good insulation & shading on west side of house, etc) are worth doing. But think about this: you are talking about a huge investment in money up front. That is capital tied up that cannot be used for anything else. That likely means debt. You are optimistically figuring a very short payback ... which is speculation. You are thinking this would be the BEST case. It could well be far more costly than you realize, and you have a great deal of expense not yet added in. Besides more equipment (such as the charge controllers) and HEAVY GAUGE WIRING, you are likely going to pay a lot of the installation itself.

Realize this: it takes a good bit of effort to monitor and maintain a solar system. Especially with FLA batteries, but as I have noted you are considering Li batteries that don't have the sort of track record to project lifespan, etc.

Now, let me ask you this: what will the power company pay you for solar production? It might be that they will pay a good 'peak rate' for supply in the sunny part of the day in summer, a time when everyone else needs MORE electricity. If they actually paid you as much as you pay them when you require electricity from them, then it might be cost effective. If you produce enough kW in the day and are selling it back to them, an r

I didn't grid tie as the rate that is paid out isn't enough to be worthwhile. It ALSO requires a full inspection before you can do that, and the NEC (national electrical code) has internal inconsistencies and many people end up with huge issues dealing with inspectors 'signing off' on their install. My situation is different as it is in a VERY rural location. No inspections necessary for construction and such, and I conceived of the property as a rural retreat. I enjoyed doing the project myself, spending about a year and a half building the structure and then doing the solar install.

Do you REALLY want to make such a commitment of capital and time? Just the fact that you were looking at a bank made of multiple small batteries means you don't know much. I mean this respectfully, not as an insult but just as an educated observation. I continue to make the effort to share my knowledge & experience as part of my goal to honor God in all that I do. I see a person in need (you!) and I have the ability to help... sometimes online forums become hostile but I truly want to be helpful for you.

Go to solarpaneltalk and do some reading on the off-grid subforum. Make a few small posts on other threads as you read. Maybe ask for clarification of some small issue. Once you get a feel for the place, then perhaps start a thread and lay out your proposal. There is one EXPERT (and he does have a great deal of expertise) who will tell you that you are an idiot, but others will be more supportive. But I suspect virtually everything I have written to you will be validated. Now I haven't been keeping up with that forum over the past 2-3 yrs, it may be that there are enough people with good experience to support the Chinese Li batteries, but it has been few and far between in the past.
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post #29 of 35 Old 02-20-2020, 01:28 PM
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Yes ... to lots of what you said. You do need some heat at times in the winter, though, don't you? The best of the minisplit units (ie most energy efficient) are heatpumps, anyway. The Fujitsu units are slightly more efficient than the Mitsubishi, but less reliable, hence my choice. It's funny as I got rather heavily focused on preparing for what may come, but like so much that we deal with, it became an idol in my life. Home theater can do the same ... just like cars, sex, money, whatever.

Anyway, I am glad to have been able to offer this to you... and I'll see you 'on the other side' one day. Just learn and look at the ups and downs of this project, talk it over carefully, and consider it prayerfully. Best wishes in your quest. Feel free to drop me a pm via this board if you wish to tell me about it as you proceed (not really appropriate to address on a home theater forum!).

Let me give one other example of how the preparedness "good intentions" can go sideways. Food storage is always an issue, as I suspect that as this virus continues to spread in China, people are going to starve as transportation is compromised. Watching severe storms paralyze people who have 2 days of food & no water, it isn't hard to see what may come. Well, as most folks are aware, freeze dried foods can last a LONG time, but are expensive. So why not do it yourself, people ask. A company happens to make a home freeze drier, rather expensive, but it does work. I considered the investment in one to have another way to store garden produce, meat, etc. Except there is a problem: these devices take a LOT of electricity! I mean a LOT! They don't give any sort of kWh for full cycle use, but these things may run for 24hrs. It is running refrigeration and a vacuum pump, both of which utilize a good bit of electricity. Making some estimates, I realized that it would take most of a day's production from my array to run one! That would NEVER WORK OFF GRID!!! Just like an electric car, it will vastly overuse your system. Think about it: you have to have a gasoline or diesel powered generator as backup to an off-grid solar array. Can you think of ANYTHING more silly than burning gasoline to make electricity to run an electric car?! Stick with gas or diesel vehicles!

Be blessed, my brother!
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post #30 of 35 Old 02-20-2020, 02:54 PM - Thread Starter
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Yeah actually I will probably not buy the EV anymore.... lol And you brought up a good point about generators. I was actually looking at diesel generators just now on local sales websites for that one day a month of blackouts here and they are a lot cheaper than a ton of batteries. So I am rethinking it and maybe just getting a grid tied system plus a generator for that one day a month and wait till the prices for lithium ion batteries go down..... I will check first with the local power company on how much they pay for net metering if it is a 1 to 1 ratio. This would cut my costs on equipment drastically.

Quote:
Originally Posted by MTBDOC View Post
Yes ... to lots of what you said. You do need some heat at times in the winter, though, don't you? The best of the minisplit units (ie most energy efficient) are heatpumps, anyway. The Fujitsu units are slightly more efficient than the Mitsubishi, but less reliable, hence my choice. It's funny as I got rather heavily focused on preparing for what may come, but like so much that we deal with, it became an idol in my life. Home theater can do the same ... just like cars, sex, money, whatever.

Anyway, I am glad to have been able to offer this to you... and I'll see you 'on the other side' one day. Just learn and look at the ups and downs of this project, talk it over carefully, and consider it prayerfully. Best wishes in your quest. Feel free to drop me a pm via this board if you wish to tell me about it as you proceed (not really appropriate to address on a home theater forum!).

Let me give one other example of how the preparedness "good intentions" can go sideways. Food storage is always an issue, as I suspect that as this virus continues to spread in China, people are going to starve as transportation is compromised. Watching severe storms paralyze people who have 2 days of food & no water, it isn't hard to see what may come. Well, as most folks are aware, freeze dried foods can last a LONG time, but are expensive. So why not do it yourself, people ask. A company happens to make a home freeze drier, rather expensive, but it does work. I considered the investment in one to have another way to store garden produce, meat, etc. Except there is a problem: these devices take a LOT of electricity! I mean a LOT! They don't give any sort of kWh for full cycle use, but these things may run for 24hrs. It is running refrigeration and a vacuum pump, both of which utilize a good bit of electricity. Making some estimates, I realized that it would take most of a day's production from my array to run one! That would NEVER WORK OFF GRID!!! Just like an electric car, it will vastly overuse your system. Think about it: you have to have a gasoline or diesel powered generator as backup to an off-grid solar array. Can you think of ANYTHING more silly than burning gasoline to make electricity to run an electric car?! Stick with gas or diesel vehicles!

Be blessed, my brother!
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