Battery Equalization

John XW NY
John XW NY Solar Expert Posts: 50 ✭✭✭✭
in Off Grid Solar & Battery Systems #1
Dear Guys

I equalized my batteries today for 1 hr on my XW to try to break up ay sulfation from sitting i waited 5 hrs and did a reading and it appeared very high, how long should i wait to get a reading?

It should read overcharge if i equalized it correct??


I used a cheapy hydrometer from auto parts store and the hose ripped a little when i stuck it in...

i would like to equalize for one more hour tommorrow to break up any sulfation .
Is that wise?
The batteries sat for a while before i got my system up and running(like 3 months)

Uhm. The problem is when i ran loads my bank shutdown after 1 hr with 1kw or less of power, low voltage disconnect.

Ok guys give me some help TY:-)
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Comments

  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    #2
    Re: Battery Equalization

    It would help if we knew what batteries. And equalization does not break up sulfation much, what you need is a constant trickle charge usually, and it can take days or even weeks if badly sulfated.
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  • John XW NY
    John XW NY Solar Expert Posts: 50 ✭✭✭✭
    #3
    Re: Battery Equalization

    Oh My Bad

    I have 12 rolls s-530 batteries in 3 sets parallel /series

    Im trying to learn

    Jah Thanks.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,622 admin
    #4
    Re: Battery Equalization

    What is the bank voltage when charging, and what is the voltage across each battery?

    Something does not sound right... I assume that this is a continuation of your previous thread (should I combine back into one thread?).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • John XW NY
    John XW NY Solar Expert Posts: 50 ✭✭✭✭
    #5
    Re: Battery Equalization

    Ok The battery voltage is reading 6.3 each battery and the voltage at the inverter cables is 25.4

    when im charging during the day volatge reaches around 29v and trickles when it is full

    is 6.3 correct?
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,622 admin
    #6
    Re: Battery Equalization

    Sounds like it is sort of correct... Using the battery FAQ:

    Charging at 29 volts is OK, Resting voltage (no charge, no discharge, rest for 3+ hours or so, ~77F) of 12.8*2=25.6v -> 6.4v full charge per 6 volt battery.

    Check each battery for 6.4x voltage level during charging (or discharging) and see that they are all just about exactly equal. If there is one battery that is high or low (>0.200 volts or so???)--you may find a bad connection/cell somewhere.

    Get a good quality replacement hydrometer and see what the cell specific gravity is.

    Are the cells "bubbling" when you fully charge/equalize the bank (almost like a fizzy carbonated soda--or almost nothing--bubble or two every few minutes).

    Do you you know how long the charger holds 29 volts and what the current is during that time?

    Your battery bank seems to act like it is under charged... Although, there could be programming issues with the Inverter too (cutoff voltage for a "dead battery" is around 21 volts. You don't want to take the bank down to that low of voltage. But if the cutoff voltage is programmed to some different level, or something like an open/high resistance connection somewhere in your battery bank wiring could make it look like a problem (or, for example too small of wire gauge and/or too long of run).

    The exact value of battery voltage depends on the battery maker and the strength of electrolyte (specific gravity)--as well as charge, temperature, and such...

    Typically, you are looking for major differences among your batteries and wiring, voltages/current that don't make sense, etc.

    At this point, you may be undercharging your battery bank--which is probably more hazardous to the bank's long term health than the risk of somewhat overcharging it.

    You really need to get a hydrometer in there and see what each of the cells is doing. If the cells show fully charged--then the issue is probably some where else. But, it still would be a good idea to measure the specific gravity after one hour and see what it reads. Also, double check the inverter volts/amps/watts reading during the discharge period.

    By the way, how do you "know" the batteries are dead after one hour? The inverter cuts off?

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • hillbilly
    hillbilly Solar Expert Posts: 334 ✭✭
    #7
    Re: Battery Equalization
    Windsun wrote: »
    It would help if we knew what batteries. And equalization does not break up sulfation much, what you need is a constant trickle charge usually, and it can take days or even weeks if badly sulfated.

    This is interesting, just wondering what you consider a "trickle charge"? Seems like there are endless strategies in terms of EQ'ing, would you mind elaborating a bit more on what you recommend for EQ/dealing with sulfation?
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  • hillbilly
    hillbilly Solar Expert Posts: 334 ✭✭
    #8
    Re: Battery Equalization
    John XW NY wrote: »
    Dear Guys

    I equalized my batteries today for 1 hr on my XW to try to break up ay sulfation from sitting i waited 5 hrs and did a reading and it appeared very high, how long should i wait to get a reading?

    So this confuses me a tad. Just what did you mean by waited 5hrs; do you mean 5hrs of no charging/discharging? As for the reading that appeared high, what reading was this and how high was it? SG, voltage, charging current...etc?

    More info is always good.
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