How does one balance 5 12-volt batteries in parallel?

barny
barny Registered Users Posts: 8 ✭✭
in Off Grid Solar & Battery Systems #1

I have 5 12-volt lead acid batteries I want to hook up in parallel to my solar panels. I want to hook them up in a balanced manner but although there is information for hooking up 4, nothing specifically for 5.  Here is what I have come up with:

Positive: 1-4, 2-3, 3 to inverter, 4-5

Negative: 1-3, 1-2, 2 to inverter, 3-5, 4-5

Am I doing this properly or is there another method?  Thanks, Mike

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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    edited October 2016 #2
    http://www.smartgauge.co.uk/batt_con.html
    This will apply to 5 batteries. Use method #3 but read the entire page as to the reasons why.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #3
    This is for a 12 volt battery bank, correct?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • barny
    barny Registered Users Posts: 8 ✭✭
    #4
    The website littleharbor2 gave cannot be found, and yes, Bill, I am using 5, 12V lead acid batteries hooked up in parallel.

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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #5
    A little garbage at the end of the link. Try this

    http://www.smartgauge.co.uk/batt_con.html

    5x 12 volt batteries in parallel is not my favorite. But if have them, might as well try and see how it works for you (follow good wiring practices).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • barny
    barny Registered Users Posts: 8 ✭✭
    #6
    Thank you, littleharbor2.  I found the page and looked at method 3 as you advised. I have one question about this setup.  I understand that the cables have to be the same length,  but how does one connect them externally before running the cables to the inverter? Thanks in advance.

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  • Aguarancher
    Aguarancher Solar Expert Posts: 315 ✭✭✭
    #7
    barny said:
     but how does one connect them externally before running the cables to the inverter?

    buss bars are the preferred method in an application like yours.
    https://www.solar-electric.com/catalogsearch/result/?q=BUSS+BAR


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  • barny
    barny Registered Users Posts: 8 ✭✭
    #8
    Thank you, Aguarancher.  For all the difference it will make, I may use method two.  In the explanation of method three, they recommend using it 'for 8 or more batteries'. Cheers.
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  • barny
    barny Registered Users Posts: 8 ✭✭
    #9
    Which buss bar would you recommend - 5 battery cables + and 5 - and the cable to the inverter for each.
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  • Aguarancher
    Aguarancher Solar Expert Posts: 315 ✭✭✭
    #10
    personally I would use method #3. buss bars are usually made of aluminum or copper. what type you use depends on what type of battery cables you use. pre-made cables imo are the way to go. call the store and they can recommend what is best for your application.  i use copper buss bars.
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  • Mountain Don
    Mountain Don Solar Expert Posts: 494 ✭✭✭
    edited October 2016 #11
    You can buy premade copper bar or plate ground.buss bars from Storm Power. They used to sell raw bar and plate stock to make your own I did that and used S/S fasteners. But I don't see the option to buy bar or plate stock anymore; just factpry made components. 
    Northern NM, 624 watts PV, The Kid CC, GC-2 batteries @ 24 VDC, Outback VFX3524M
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  • Marc Kurth
    Marc Kurth Solar Expert Posts: 1,174 ✭✭✭✭
    #12
    @Mountain Don - your link is missing the colon after http in your link:

    http://stormpowercomponents.com

    Marc
    I always have more questions than answers. That's the nature of life.
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  • barny
    barny Registered Users Posts: 8 ✭✭
    #13
    I have it figured out - thanks everyone for your help.


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