moving batteries

offgrid me
offgrid me Solar Expert Posts: 119 ✭✭
in Off Grid Solar & Battery Systems #1
I have a newly commissioned 48v battery bank consisting of 2 strings of 8 6v batteries. I was wondering if there would be any advantage in changing each batteries location in the string every couple of months. Would I gain any longevity by moving the middle batteries closer to the ends and vice versa the end batteries to the middle.
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: moving batteries

    If all is wired right, no. Just check the SG on them regularly and make sure they're staying even.

    It is possible to have "inside" batteries get warmer than "outside" batteries in a bank (and thus perform differently), but with just two strings in parallel the temps should be fairly equal and they should all behave the same.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,649 admin
    #3
    Re: moving batteries

    Getting a DC Current Clamp meter to monitor heavy loads/charging currents to makes sure each string is properly sharing and measuring once a month or so we be a nice sanity check on wiring/cell performance.

    Some people believe the simple act of moving/bouncing the batteries around a bit is helpful to keep them stirred up.

    Others here believe that middle batteries should be rotated with end batteries once in a while.

    If you monitor specific gravity and battery/cell voltage (and log)--you will quickly see if there are any locations/cells that perform "different" than their neighbors.

    At that point, you can try rotating (and/or cleaning/torquing wiring connections, etc.) battery locations and see if it makes a difference for you.

    I am of the opinion that any advantages of moving (longer battery life/better performance over time) is probably just about canceled out by the chances/risks of messing things up (stripping bolts, short circuits, contaminating electrolyte, dropping tools on top of batteries, putting a hole in a case, etc.).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #4
    Re: moving batteries
    BB. wrote: »
    etc.) battery locations and see if it makes a difference for you.

    I am of the opinion that any advantages of moving (longer battery life/better performance over time) is probably just about canceled out by the chances/risks of messing things up (stripping bolts, short circuits, contaminating electrolyte, dropping tools on top of batteries, putting a hole in a case, etc.).

    -Bill

    Agree. Mine have been in same positions for over 5 years, the batteries are nearing 10 years, just rechecked SG 2 days ago, as I have every couple of months when I add water, and all is still perfect. BTW, I have three strings of two L-16's, and to make sure all charge and discharge equally, all three 12 volt + terminals are connected with equal lengths of cable to a single point. Same with the negative terminals. So far that has worked great for me, but that's not necessary with just two strings.
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  • techntrek
    techntrek Solar Expert Posts: 1,372 ✭✭✭
    #5
    Re: moving batteries

    offgrid me - take a look at this page

    http://www.smartgauge.co.uk/batt_con.html
    4.5 kw APC UPS powered by a Prius, 12 kw Generac, Honda EU3000is
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #6
    Re: moving batteries

    I rotate my battery positions every time I rotate my light bulbs.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #7
    Re: moving batteries
    mike90045 wrote: »
    I rotate my battery positions every time I rotate my light bulbs.

    Does that include the disco ball? :p
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  • arghhh
    arghhh Registered Users Posts: 18 ✭
    #8
    Re: moving batteries

    We don't rotate UPS batteries in a string and never show certain cells degrade more than others. This is 40 in a string as well. I have seen a 240 battery string of 2volt cells installed for 12 years now that has only just started failing cells.
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