Adding electrolyte to empty, used batteries

olNick

Hello all,

New user here. Off grid since about 2000.

My old bank, 2 12 volt strings, 1500AHr total (OPzS 2 volt cells)  finally gave up the ghost; simply refusing to take any real charge, and alot of shedding at the bottom. Had the them about 14 years.

Shame, I really abused the heck out of them, yes, classicaly never having enough PV and always undercharged. Live and learn.

Been given a set of 6 OPzS, 600AHr that were sitting for 1 1/2 years w/o electrolyte :-( (too heavy for them to move)

My friend/dealer took over filling them, and giving an initial charge.

Had some very sunny days and I've charged the batteries @ 45 amps 'til I got about 2% current going through them. Voltage reads ~ 12.8 v full. Have not had a chance for a load test yet.

I checked and the SG though is only 1.13-1.14

Friend says to keep charging and the SG will come up. I really doubt that.

I think I should either add acid to them to bring SG up to 1.24 (recommended by manuf.) Easier said than done....

Or, easier for me is to empty and add acid at the correct SG.

What do you guys say?

Possible I might be given another identical 600AHr set of six(originally a 48v bank) to parallel with these, also wo electrolyte.

edit: Forgot to mention that the "new" batts were in service for only a couple of years, and have no sulfation, shedding etc. 
PO replaced the 48v bank with a much higher capacity VRLA (OPzSV) set more suited to his needs.

regards,

Nick

Live in Crete btw

mike95490

If a battery was filled with electrolyte and then drained dry, the dried portions of the plates become inactive.   So you may have some nice looking boat anchors

Give them a couple good charge and discharge cycles, and you will know more after a few cycles

BB.

Generally, sulfated batteries are non-recoverable... However, you can find lots of methods on the Internet how people "recover" such batteries (if they get 20% capacity, they seen to be "happy"?).

If the batteries have been stored without any liquid electrolyte and the cells are not sealed (vent caps still in place), typically the plates oxidize (corrode) and are "no good" anymore.

-Bill

olNick

Thanx for the replies. Luckily the batts had sealed caps and the plates look clean (what's corrosion look like?). 
I'll be getting another set of 6 these days and plan to fill with electrolyte at the stated SG of 1.24.

IS THIS CORRECT to fill with 1.24 right off the batt (pun) or a little less and then adjust?

Should I fill em with anything to clean and then flush with distilled to get rid of any corrosion? Baking soda?

Already have 12 beautiful boat anchors already:-(
appreciate it.

Nick

mike95490

Adding baking soda will destroy the battery,  you will never be able to rinse it all out, unless you do a rinse with plain battery acid and toss the acid.  even then, leftover ions will poison the electrolyte. 
 We lost everything in a wafer lab, when a baking soda based fire extinguisher was used for a small trashcan fire that should have been just carried out to the hallway.  All the product and equipment had to be scrapped, we spent weeks trying to clean and were never able to clean it up. Believe it or not, batteries are very sensitive to contamination in the electrolyte, be it well water, or a baking soda rinse.