[RE-wrenches] Interstate UL-16 HC problem

[jay peltz]

HI Tom,

Are you saying that you are seeing 14 years on a single string of L-16's?
If so I would like to hear your charging  recommendations.

thanks,

jay

peltz power
On Jun 30, 2010, at 9:32 AM, The Office of Tom Duffy wrote:

> Bob
>  
> Yes the problem is hard sulfation due to chronically under charging. The absorb time and voltage is the most critical charge mode for charging batteries. The default settings on inverters and charge controllers are always way too short, so they hold the batteries in absorb for a little while, then go to float, leaving the batteries under charged forever, thus we get hard sulfation. This is what you have here. Typically two parallel strings will yield about 6 ½ years of life in a system that is used off grid. While a single series string will yield 10 to 14 years (properly maintained) 14 years is not the rule however.
>  
> A bit of due diligence is now required to get these back, (and they may not be worth it). Separate the two strings and give them 62 volts for 10 hours; you’ll have to watch them so they don’t get too hot. Set the absorb settings below and give them about three weeks. If there is some improvement in capacity, another EQ; 61 volts for two hours may just do it.
>  
> With the Magnum 48 volt inverter I calculate the absorb time at 5 hours, now typically the absorb charge should be about 58.8 volts but, most batteries die because of under charge so I would set the absorb voltage at 59.4. You may have to update the software for the Magnum control panel to get more programming flexibility.
>  
> The MX60 with 6 of the 175s should be set to absorb for as long as possible, I think the last software version allows 4 hours. I calculated absorb time with this setup is 19.6 hours which is not possible, so just keep the controller from going to float for as long as you can.
>  
> Concord makes a real nice 915 AH 2 volt cell which should give a decade plus life, for the next bank. I would avoid parallel strings at all cost. If you feel this is too large a bank then use the 660 AH 2 volt. You can always call me 575-539-2111 if you have questions. I have been in the battery business almost 45 years.
>  
>   Tom Duffy
>   Systems Design Engineer
>  
>      tom at thesolar.biz
>        575-539-2111 X 301
> Although no trees were killed in the sending of this message, a large number of electrons were terribly inconvenienced.
>  
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