Battery voltage 6v or 12v

What does the forum recommend 12v or 6v. for solar systems? the 6v has more amp hrs. Was thinking of running two 6v 216amp hrs in series. Should I go with 6v or 12v, whats the best bang for the buck.

Comments

  • bsolarbsolar Solar Expert Posts: 103 ✭✭✭
    Re: Battery voltage 6v or 12v

    I was watching a youtube video of a guy with a nice system talking about batteries .. the 6V batteries have thicker plates so theyre heavier duty. The golfcart type batteries with no cold cranking amp info and only amp hour rating are the best according to him and are designed to be 'taken down' on a regular basis and last several years .. most automotive and even deep cycle marine batteries are designed for 300 or less 'cycles' according to this guy, and generally last less than a year if you plan on actually using the system regularly for anything other than backup power .. So i myself gathered from all this that putting 6V gilfcart type batteries in series is definitely the ideal situation for solar ..

    http://www.youtube.com/watch?v=DR7XKFe4b9E&feature=mfu_in_order&list=UL
  • BB.BB. Super Moderators, Administrators Posts: 31,765 admin
    Re: Battery voltage 6v or 12v

    You have several questions to answer... Bank Voltage (12/24/48 volt)--typically less than 1,200 watts power, 12 volt will work OK. over ~2,400 watts you should look at a 48 volt battery bank.

    Personally, I do not like lots of batteries in parallel... More water levels to check, difficulty getting current sharing among the strings, more fusing/wiring for each parallel connected battery string, difficult to diagnose battery problems (shorted/open cells are not obvious).

    It becomes easier if you get a Clamp on DC Amp Meter (like one of these) to measure each current path.

    My own recommendation is to not have more than 2 or 3 strings in parallel (although, many people have more and are happy with them).

    And I would suggest get as large as battery AH rating as you can physically move (and appropriate for your system design).

    So, two 6 volt 225 AH batteries in series for 12 volts is (in my humble opinion) better than two 12 volt 112.5 AH batteries in parallel (all things being equal).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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