Battery for my first setup?

ludude1975
ludude1975 Registered Users Posts: 2
in Solar Beginners Corner #1
I already have a 1500 watt modified sign wave inverter and I want to try a solar setup for backup / trial.

My ideal start-up will be a couple Grape Solar 100 watt panels @$199 each I can get from Home Depot.
A Morningstar Sunsaver MPPT Charge Controller 15A for $199

I want to buy local batteries to start up a bank ideally I can add up to about 800ah but for starter realistically I'm going for half that to hopefully get a couple hours use to run lights and TV in a power outage.

There's not much of a place to get batteries around here, auto parts stores, Rural King sells golf cart batteries, Tractor Supply Co. Wal-Mart, etc. Only one battery specialty store close and I have had bad luck getting so much as a working car battery from them so I'd rather avoid them. I think the golf cart batteries are like 6v around 100ah but not really sure. I figure 4 of them series parallel would give me 12vdc @400 ah ?

I'd really love to start out 24v but I have several $1k's for a setup. Any ideas on a beginners battery I can get preferably new from a local type chain store?

Thanks for reading!
Chad
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Battery for my first setup?

    Welcome to the forum.

    Let's look at each item in turn.

    1500 Watt MSW inverter. Don't be surprised if this fills your TV with noise. Shouldn't have any trouble with incandescent lights. CFL's could 'flicker'.

    Two 100 Watt Grape Solar panels for $199 each. Together they'll put out about 10-11 Amps, a good charge rate for 100 Amp hours of battery. Would not do much for 800 Amp hours, but then you really do not want 800 Amp hours @ 12 Volts believe me. 100 Amp hours would give you an absolute maximum of 600 Watt hours available, probably a little less.

    Golf cart batteries tend to be 220 Amp hours @ 6 Volts. Two of these in series would give you 220 Amp hours @ 12 Volts and would just recharge from 200 Watts of panel providing they aren't drained down much and you've got plenty of sunlight. The rate would be just under the 5% recommended minimum. It would double your available Watt hours. Sometimes you can get these really cheap from places like Sam's or Costco.

    Usually you pick the battery first by choosing the right set-up to supply enough power to meet your needs, which is a matter of both the Watts being used and the hours they're used for. Then you get the right combination of panels & controller to recharge the batteries.

    I'd better add that for back-up power solar is an incredibly expensive choice. But I suspect this is also a case where you want to experiment and learn, n'es pas? :D
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #3
    Re: Battery for my first setup?

    Assume your inverter is a 12 volt one, as Mr coot says the msw inverter is not a good choice for electronics.24 volts from the start is good idea if you can, do it from the start. Price for a 12 volt controler will be the same a a 24 volt one. Also as your getting new pannels 2 with 22 volts open circuit set in series will be good for a 24 volt system. So your only additional cost is a new 24 volt inveter ( go for a pure sine wave one if you can ). If going 24 volts consider a single 24 volt panel as $ for watt they are often cheeper.
    My system grew from 120 watts over the years to 1200 watts, unfortunately still at 24 volts, But in saying that it works very well for a holiday home set up..
    All the best with your adventure into solar, this is a fantastic site to learn from.
    Regards Peter
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #4
    Re: Battery for my first setup?
    ludude1975 wrote: »
    I think the golf cart batteries are like 6v around 100ah but not really sure. I figure 4 of them series parallel would give me 12vdc @400 ah ?

    I'd really love to start out 24v but....

    As Cariboocoot wrote, GC batteries are typically 6 volt 220 ah. If they were 100 ah and you put four in series/parallel, the resulting bank would be 12 volts 200 ah, not 400 ah. When you put batteries in series, the voltage goes up, but not the ah.

    btw, if you did buy 4 GC batteries (but you don't have enough panel to charge them) you could put them in series and have 24 volts. The energy storage (in kilowattHours) is the same either way. It is always advantageous to have a single series string of batteries rather than multiple parallel strings.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #5
    Re: Battery for my first setup?
    petertearai wrote: »
    My system grew from 120 watts over the years to 1200 watts, unfortunately still at 24 volts,

    Hahaha This is also the history of my system, with one difference - - - I only Wish my system was 24 volts - - instead of 12 volts as it is. :cry:
    But in spite of being 12 volts, by using very large wires and extremely good, solid connections etc, it does work very well, and for that I'm very thankful! :cool:
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  • ludude1975
    ludude1975 Registered Users Posts: 2
    #6
    Re: Battery for my first setup?

    Series voltage goes up Parallel more amperage increases, I know I should have known that but I was tired when I started writing LOL. I have a smaller 325 watt inverter that came from Meijer some time back and it seemed to run my 40" JVC LCD TV OK off my truck's Optima Red top battery, but I guess I'll test it out on the 1500W first before i get to carried away. It was a struggle for it and it wouldn't run it and the cable box so I had to tie to the antenna. That was what got me on the idea to solar charge some batteries.

    Unless someone can recommend a good startup / setup I can build on for less than a grand, I guess I'll have to wait till I get more cash flow to start this project cause I was only thinking on taking about $1000 from my tax refund to tinker with, the rest are to clear off my Christmas bills which are more important then paying the ridiculous % interest.
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  • Photowhit
    Photowhit Solar Expert Posts: 6,006 ✭✭✭✭✭
    #7
    Re: Battery for my first setup?
    ludude1975 wrote: »
    I'd really love to start out 24v but I have several $1k's for a setup. Any ideas on a beginners battery I can get preferably new from a local type chain store?

    I just picked up 4 golf cart batteries from Sams Club in Columbia MO, I think they were right at $82 each, and Sams club isn't particular about your trade in for the core charge, I actually cracked one of the car batteries I had been saving to trade in, when I was trying to seperate 4" of earth that was frozen to the bottom I cracked the case. So I took in a large garden tractor battery ad they accepted it against the $15 core charge!
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #8
    Re: Battery for my first setup?

    Hi Wayne . Spotted my typo .Should have said still at 12 volts like you are. And yes my system is working well, only problem , batterys dont get a proper work, typically only getting down to around 93% over night. Seems you cant win with batterys. Either they are too small or too large or you don't have enough pannell or something else. Regards Peter
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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