Sun Extender Battery Problem

monoloco
monoloco Solar Expert Posts: 103 ✭✭
in Off Grid Solar & Battery Systems #1
Recently, I noticed that my batteries were very low in the morning, upon investigating I found one that was substantially lower than the rest so I split my bank of 8 Concorde Sun Extender 305 AH batteries into two banks and charged them separately to try and bring it up. When I am absorbing the low battery shows a higher voltage than the others but very rapidly falls to 6.23 volts when taken off the charger, in the morning after resting all night it reads 5.50 volts. Is this battery toast or is there something I should try and do to bring it back? These batteries are less than 3 years old and have never been abused or excessively discharged. I was considering equalizing the bank but am afraid I could damage the other batteries. I have never equalized them in 3 years.
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  • jcheil
    jcheil Solar Expert Posts: 722 ✭✭✭
    #2
    Re: Sun Extender Battery Problem

    Can you check the SG of the cells or is it a sealed battery?

    Also, do you have a load tester? Like the old-school automotive heating element type? I find that is a good way to determine if there is a weak/bad battery.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #3
    Re: Sun Extender Battery Problem

    You can equalize them, but you need to follow the Instructions close, sealed batteries are tricky. Be especially mindful of the Batteries temperatures. It really would be best to do that one battery by it's self and get it up, then do the whole bank, but I doubt you have the equipment. That one battery will have a tendency to be hotter than the rest, so watch it close. I have water tank I sit them in. Yeah, you could load test it, but you already know the problem.

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  • monoloco
    monoloco Solar Expert Posts: 103 ✭✭
    #4
    Re: Sun Extender Battery Problem

    I just spoke with a Concorde tech and he believes that the battery is bad and should be replaced. Ouch!
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #5
    Re: Sun Extender Battery Problem
    monoloco wrote: »
    I just spoke with a Concorde tech and he believes that the battery is bad and should be replaced. Ouch!
    It could be, hard to tell without seeing how it reacts. I guess he offered you some warranty help ??
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  • monoloco
    monoloco Solar Expert Posts: 103 ✭✭
    #6
    Re: Sun Extender Battery Problem
    Blackcherry04 wrote: »
    It could be, hard to tell without seeing how it reacts. I guess he offered you some warranty help ??
    Warranty's expired, no help offered.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #7
    Re: Sun Extender Battery Problem
    monoloco wrote: »
    Warranty's expired, no help offered.
    That sux's, try conditioning them for a hour or two and see if it shows any improvement. At 3 years, if you'v never done them , it won't hurt. if you know someone with a variable power supply, you can do it by it's self. How many volts is it ??

    I bought 2 batteries from Sam's yesterday, last months production, I am on my 3rd hour equalizing them and they are just now coming up.
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  • monoloco
    monoloco Solar Expert Posts: 103 ✭✭
    #8
    Re: Sun Extender Battery Problem
    Blackcherry04 wrote: »
    That sux's, try conditioning them for a hour or two and see if it shows any improvement. At 3 years, if you'v never done them , it won't hurt. if you know someone with a variable power supply, you can do it by it's self. How many volts is it ??

    I bought 2 batteries from Sam's yesterday, last months production, I am on my 3rd hour equalizing them and they are just now coming up.
    They are 6 volt. I am wishing that I would have gone with 12 2volt batteries in one string, I think that parallel strings are the problem, it seems like there are always some batteries that get overcharged and some that get undercharged. Oh well, live and learn, next time I'll know better.
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #9
    Re: Sun Extender Battery Problem
    monoloco wrote: »
    They are 6 volt. I am wishing that I would have gone with 12 2volt batteries in one string, I think that parallel strings are the problem, it seems like there are always some batteries that get overcharged and some that get undercharged. Oh well, live and learn, next time I'll know better.
    I'd try EQ'ing them, you really don't have that much to lose. Or try to find another used 6 V battery, a new one will just drag down. 2v can have the same issues. I hate batteries ...... . Truthfully, I'v never had luck with sealed batteries after 3-4 years. If they are cycled they go bad or if they are on float service they go bad.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #10
    Re: Sun Extender Battery Problem

    you can try to hold onto hope, but imho the battery has a bad cell. you are kind of stuck needing to replace that battery and have this new battery degrade to the level of the other batteries at 3 years of age or go ahead and replace them all at a much higher expense. we don't like to think about batteries going this soon, but in reality any battery can go bad even within a year. too bad they don't extend the warranty for the concordes even on a pro rated basis as that would've eased your pain a tad.
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  • monoloco
    monoloco Solar Expert Posts: 103 ✭✭
    #11
    Re: Sun Extender Battery Problem

    I ordered a new one, $450, yikes.
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  • Thom
    Thom Solar Expert Posts: 196 ✭✭✭
    #12
    Re: Sun Extender Battery Problem
    monoloco wrote: »
    I ordered a new one, $450, yikes.

    Wow !!
    My 4 gc 6v are only $300.
    Off grid since 1984. 430w of panel, 300w suresine , 4 gc batteries 12v system, Rogue mpt3024 charge controller , air breeze windmill, Mikita 2400w generator . Added 2@ 100w panel with a midnight brat 
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  • monoloco
    monoloco Solar Expert Posts: 103 ✭✭
    #13
    Re: Sun Extender Battery Problem

    I left the bad battery connected in a string with 3 good ones, but not connected to any load or charging source. I checked the voltages of the batteries after a couple of days and the 3 good batteries all read 6.3 or 6.4 and the bad battery that was at 5.5 volts previously, was now showing 6.18 volts, I switched my leads over to see what would happen if I tried to charge the bank and the charge controller immediately went to float and the voltage of the bank was reading 29.1 volts. Does anyone know what the heck's at work here? I have a new battery on the way, but I thought that I would experiment with trying to resuscitate the bad one a bit, but I don't want to risk damaging the other batteries. I really wish that I had a 6 volt charger so I could isolate that one battery.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #14
    Re: Sun Extender Battery Problem

    put it through its paces to be sure you won't need to return that battery.
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  • YehoshuaAgapao
    YehoshuaAgapao Solar Expert Posts: 280 ✭✭
    #15
    Re: Sun Extender Battery Problem

    Standard-grade deepcycle golf cart batteries only last 2-5 years though. But Group 31 and GC2 are definitely the most economical battery sizes for sure.
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  • monoloco
    monoloco Solar Expert Posts: 103 ✭✭
    #16
    Re: Sun Extender Battery Problem

    Should I equalize the batteries when I replace the defective battery? When equalizing, is it better to split the batteries into two banks and equalize them separately?
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #17
    Re: Sun Extender Battery Problem
    monoloco wrote: »
    Should I equalize the batteries when I replace the defective battery? When equalizing, is it better to split the batteries into two banks and equalize them separately?

    Absolutely. When you equalize you are overcharging most of the cells so that you can get the weakest of them fully charged. The fewer cells you can overcharge the better. Also, there are the issues of parallel batteries... if they do not split the charge equally (and they don't) you may be dangerously overcharging one battery, especially if you have an open or shorted cell.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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