Trouble with new battery bank

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System
System Posts: 2,511 admin
in General Solar Power Topics #1
I just installed a new 6 x 6 volt golf cart cart battery array in my RV to give me 12 volts.

The new voltage from this pack quickly settles at 12.4 volts in the evening just after the sun goes down, and this is lower than the set of batteries that I replaced! Not exactly what I had in mind for my $400!!!

I think I did most things right - cleaning the terminals, cables, and so on, but there is one things that was different.

The new batteries were not "full", so I added pure water (between 4 and 8 oz per cell) to bring each cell up to the bottom of the fill tube. I did this because when installed, the back set of batteries is hard to get to, and I wanted to make sure the electrolyte level was optimum. I did not charge the new batteries before I did this.

FYI - the charging systems are exactly the same as I used with the old batteries, so don't let's go there.

Possibly I did something stupid, and if so, please gently let me know. But I am wondering if this was an error on my part, will it correct itself in time, or is there someting I can do to get these batteries to start functioning properly?

Thanks

Brian
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #2
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    Re: Trouble with new battery bank

    Your new battery bank is rated for ~675 Ah x 12 V. A 12.4 V reading is not good... are there any loads on the batteries? If so, you'll need to remove all loads (as well as charging sources) for several hours before taking a voltage reading to establish an accurate state-of-charge.

    Unfortunately, we may have to "go there". The practical minumim charging current for a flooded-cell battery bank is about 3% of capacity. That would be ~20 A for a 675 Ah bank, or a PV array in the 340 W range. What have you got?

    HTH,
    Jim / crewzer
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  • System2
    System2 Posts: 6,290 admin
    #3
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    Re: Trouble with new battery bank

    According to U.S. Battery web site:

    "New batteries need to be cycled several times before reaching full capacity (50 - 125 cycles, depending on type). Usage should be limited during this period."

    http://www.usbattery.com/pages/usbspecs.htm

    I can only presume this is generic information for all wet cell lead-acid batteries.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #4
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    Re: Trouble with new battery bank

    those batteries have suffered damage if the plates were exposed to the air as you indicated you had added quite a bit of water to it. sulfation has probably set in heavilly.
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  • System2
    System2 Posts: 6,290 admin
    #5
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    Re: Trouble with new battery bank

    You know if those are US Batteries you will have to bring each cell up to 2.583 volts or 15.498 volts 12 volts for a couple of hours to get a full charge on them. If you had an other brand and you were charging them to 14.7 you have not charged a set of US Batteries yet. You did say 12 volt battery system so try holding the charge at minum of 15.0 to 15.1 volts for 2 to 4 hours.

    Only do the above if you have flooded US Batteries.

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  • System2
    System2 Posts: 6,290 admin
    #6
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    Re: Trouble with new battery bank

    .....just a note from past experience. :cry: The level of electrolyte will RISE as it charges. If you added water to fill up the cells when it was discharged, than expect to clean up a mess when you FULLY charge the batteries.  You should only add enough water to cover the plates on a discharged battery before charging.  After a full charge, than add water(distilled) and charge again (short equalizing charge) to stir up the electrolyte. :wink:
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  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    #7
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    Re: Trouble with new battery bank

    Deka / East Penn says their VRLA (gel or AGM) battery specs apply after 15 cycles. Bill Darden suggests that "some new batteries can take up to 30 charge/discharge "preconditioning" cycles before they reach their rated capacity."

    HTH,
    Jim / crewzer
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  • System2
    System2 Posts: 6,290 admin
    #8
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    Re: Trouble with new battery bank

    I certainly don't want to overstep my bounds here but wouldn't it be better if people had
    to register before being able to post.. i know it wouldn't stop all the bs but it would stop
    the redirectors and a lot of stuff like above.

    brad
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    #9
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    Re: Trouble with new battery bank

    I have a general rule. Don't buy a battery that reads less then 12.6 vdc. (or 6.3 vdc for 6 v battery) After charging and an open circuit overnight rest it should read 12.7 vdc.

    If it had been sitting below this voltage for a month or more it will be sulfated.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #10
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    Re: Trouble with new battery bank
    pioneer wrote:
    I certainly don't want to overstep my bounds here but wouldn't it be better if people had
    to register before being able to post.. i know it wouldn't stop all the bs but it would stop
    the redirectors and a lot of stuff like above.

    brad

    don't worry brad as one of us usually eliminates it sooner or later. it won't stop it all as i found somebody who registered and did it. they are on probation so to speak. i doubt they will post again, but if they do it better not be spam again. :x
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