Battery bank

BETTER2BE · April 2012

IM JUST STARTING TO BUILD A SMALL SOLAR SYSTEM FOR MY HOME, SO FAR I HAVE A 12 V 250 W PANEL FROM GRAPE SOLAR , A MORNINGSTAR TS60 CHARGE CONTROLLER W METER AND A 2300 W INVERTER WITH ONLY ONE 12 V DEEP CYCLE LEAD/ACID BATTERY,
CAN ANYBODY GIVE ME SUGGESTIONS ON BUILDING A QUALITY BATTERY BANK SO I DONT WASTE MONEY ON THE WRONG TYPE OF BATTERY? IS THERE A DIFFERENCE IN A HIGH RATE BATTERY VS DEEP CYCLE ? AM I LOOKING FOR A HIGH AH BATTERY ? I WANTED TO HAVE AT LEAST 4 12V BATTERIES IN PARALLEL. i WAS HOPING TO BE ABLE TO RUN MY FRIDGE , A TV . LIGHTS AND SEVERAL OTHER LOW AMP DEVICES
ANY SUGGESTIONS ON BATTERIES WOULD HELP ! THANKS 8)

vtmaps · April 2012

Re: Battery bank

Welcome to the forum. NO NEED TO WRITE IN ALL CAPITAL LETTERS. First of all, to answer your question about batteries
read: http://www.windsun.com/Batteries/Battery_FAQ.htm

Second, you say you want to have at least four 12 volt batteries in parallel? Bad idea!
read: http://forum.solar-electric.com/showthread.php?14674

Third, you are approaching this whole thing backward. You need to know precisely what your loads will be. Get a kill-a-watt meter. Then you can rationally decide what battery capacity you need and what voltage your system should be. I can say right off that it is generally not a good idea to be running a 2300 watt inverter off of a 12 volt system.

Fourth, it is always a good idea to understand why you want a small solar system. Are you on the grid? Are you doing this to save money? Are you doing this as a backup to the grid? You can get all sorts of good friendly advice here, but we can't read your mind... tell us more about what you are trying to accomplish.
--vtMaps

waynefromnscanada · April 2012

Re: Battery bank

Welcome to the form "BETTER2BE"
You came to the right place for educated and experienced answers.
I agree with vtmaps on all points, in particular the 2300 watt, 12 volt inverter. Reason being, the bigger the inverter, the greater the idle power consumption just to keep the inverter running, plus, if loaded to it's max rated power, you'd be looking at more or less a 200 amp draw on your 12 volt battery, which is huge, and that's not taking into consideration any surge loads, which could be double the continuous rating. Think of it this way - - many car starters draw "only" 100 amps while starting the engine - - how long can you crank your engine before the battery is dead - - - . Inverters don't wait for the battery to go dead, they shut down as soon as the voltage drops to perhaps 10.5, which will happen very quickly with a large load, unless you have a really big battery bank. Also check into the differences and usefulness of MSW (Modified Square Wave) inverters, compared to pure sinewave inverters, as I have a feeling your inverter is likely MSW.
There is so much to learn, and this is the form that will give you the best answers. The answers may not always be what we want to hear, but they are honest, truthful answers.
Good luck with your system.

BETTER2BE · April 2012

Re: Battery bank

Thank you for the advice, being totally green I know I have alot to learn , I have absorbed so much info Ive managed to confuse myself. Let me start over , you are correct I have purchased a Power Bright PW 2300-12 4600 W Peak , 19.2 amps Modified Sinewave.. My goal is to build a system that can reduce my electric bill which averages 400 to 500 a month , having a pool , hot tub and 2 AC units doesnt help. I will continue to research and try to install what is needed correctly to accopmlish this task . (Off Grid system ) my county does not allow Grid tied systems unfortunatly.
I need advise on setting up my system to get the most out of it and add panels and batteries as I can afford. So with the TriStar TS60 w meter , the 250watt panel and the 2300 watt inverter plus one 12 VDC deep cycle ... have I started out wrong? I will call Northern Ariz for tech support as well . With the equipment I have now ,if it where you , how would you set up ? again thanks for you assistance I will continue to research
Dave ( newb )

BB. · April 2012

Re: Battery bank

Hi Dave and welcome to the forum!

Yea--more or less, you have started wrong (pretty much were everyone here has started too. :roll:).

If you want to save money, you need to look at Grid Tied solar (solar panels + GT inverter connects to your home wiring). It basically adds solar power to your AC wiring and causes the meter to spin slower--and even backwards during the day (note: meter behavior depends on your utility and their billing plan(s)--it can be a fairly complex problem to analyze with 1 year net metering, time of use, tiered power rates, minimum billing, and other issues--and some utilities do not support GT/net metering and connecting a GT system can actually increase your power bill or get your home red-tagged).

Anyway--We really push measuring your energy usage (your power bill, kill-a-watt meter, T.E.D., etc.) and looking to reduce your power usage (insulation, energy star appliances, turning stuff off when not in use, etc.).

It is almost always cheaper (and more cost effective) to conserve than it is to generate power.

With modern Grid Tied systems, they are pretty close to parity with the $$$/kWH for grid power--and sometimes even much less (I have Time of Use/Tiered charging which can push power rates to ~$0.50 per kWH on summer afternoons). You can get in the range of $0.20 to $0.07 per kWH or so for GT power (government tax credits, etc.--of course depending on where you live and how much sun your roof gets).

For off-grid systems (panels+charge controllers+batteries+inverters)--Their high costs (batteries+extra hardware), extra conversion losses (battery bank+inverter), and expensive maintenance (battery replacement every ~5-10 years, new inverters/charge controllers/electronics every ~10+ years) can easily push the cost of power into the $1 to $2+ per kWH range... (some people have done it for less--but this sets your expectations).

In the end, even though this is a Solar and Wind forum, we really spend a lot of time talking about/helping with conservation and loads--And once that has been all nailed down--then we talk about solar PV/etc. part of the equation.

And you have to be very careful about conservation--there are a fair number of "green scams" out there too.

-Bill

waynefromnscanada · April 2012

Re: Battery bank

BETTER2BE wrote: »

Thank you for the advice, my county does not allow Grid tied systems unfortunately.

So he's stuck with going off grid - - - - Almost impossible to save money - - - - Trying to be gentle with this answer. What more can I say except that off grid power, ALL things considered, often costs ten times what the same kwh would cost from the grid

westbranch · April 2012

Re: Battery bank

well, there is solar water heating to augment the (assumed) electricity used to heat the pool and hot tub. Not cheap up front but is a long term solution.

BETTER2BE · April 2012

Re: Battery bank

Thank you , very helpful good info ! Dave

BETTER2BE · April 2012

Re: Battery bank

ok thanks for the info ! very helpful , Ill take all the advise I can get . Dave

Battery bank

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