AGM Battery Desulfator

huntep

I just acquired four AGM NSB-170Ah telecoms batteries which were being replaced... I have them connected to my charge controller XW mppt60-150 which seem to do a good job of charging them up. However, I was wondering if the controller acts as a desulfator or should I equalize them or what?. They dont seem to stay up very long. The current setting for the charge is AGM and 3stg. bulk, abs, float...

Thanks for allowing my post.. Very interesting forum. Keep up the good work.
BTW I have hybrid XW4024 with 6X195 Sun panels and XWMPPT60-150 Charge cntrl.

mike95490

Re: AGM Battery Desulfator

I'd suggest you try a couple 80% charge/discharg cycles, to "open up" the plates that have sat in float for 5 years.

Also, they are likely disposing of batteries that are 5 years into their 7 year life, and may not have much left in them. What was their voltage when you got them ? If much under 12.5V, they are likely toast.

AGM should not never, ever be equalized, unless you have specific instruction from the Mfg on how to do it, and how to monitor and measure the process. DONT DO IT !

waynefromnscanada

Re: AGM Battery Desulfator

mike90045 said it better than I could have. Totally agree with him.

BB.

Re: AGM Battery Desulfator

Here is a thread how one company (Concorde) recommends to "recover" their AGMs... Not supposed to apply to any other brands of AGMs:

Sulfated Lifeline Concorde AGM Batteries

And here is a great thread from DapDan with information on how one place recommends to restore AGM batteries (new catalyst caps, adding water to cell, etc.):

Low rest voltage on GNB absolyte IIP cells

In the end, trying to do "extreme" things to batteries should be done in a safe area and always under some sort of supervision/monitoring (don't want to overheat the cells and blow acid around) and performed while wearing appropriate safety gear/gloves/face shield/water/hose/baking soda nearby/etc.).

And--if the cells are otherwise scrap--if you can try some of the above things (if done safely)--you are not loosing much anyway.

-Bill

niel

Re: AGM Battery Desulfator

"They dont seem to stay up very long."

what exactly do you mean by this? give detail.

westbranch

Re: AGM Battery Desulfator

re "They don't seem to stay up very long."

you also need to test them as per the manufactures load testing procedure, usually a 20% of rated capacity, and record the results to compare against the Manufacturers tables. This will help in assessing battery health...

Eric

huntep

Re: AGM Battery Desulfator

Thanks everyone for your input.. I found the problem, one battery had a hairline crack on the side and caused the bank to fail prematurely.i.e. after about two hours. AGM dont leak even with a crack...(12 batteries in series/parallel 24v) system. I can run all night now after replacing it.

westbranch

Re: AGM Battery Desulfator

here is some condensed info I received from an AGM servicing company a while ago, you may find helpful.

Eric