Deep cycle battery question

[Bear]

Can deep cycle batteries that were allowed to lose most of the battery acid be saved?
Eight batteries in a UTV needed 71/2 gallons of distilled water to top them off, then charged. They lose power much quicker then before. Can they be dumped and new battery acid added? or will this not work?

 

[wrcsixeight]

If the battery acid spilled out, and quickly replaced then yes.

If it bubbled out through hydrolysis from being kept at too high a float voltage, then likely not.

Whenever I've let a battery get low it instantly lost capacity, and older batteries half way through their life were killed with little usable capacity remaining.


YOu can try charging them upto 14.8v until amps taper to about 1 amp, then bump voltage upto 16 and see if the specific gravity responds, but they are likely toast and not worth the effort, and having a charging source which can actually do an equalization charge is another matter

 

[4wheeldog]

I would say there is very little hope that those batteries will have much of their original capacity left.

They have likely been subject to overcharging. The plates have likely warped, and there is likely plenty of fall out matter in the bottom of the batteries, either from sulfation or corroded lead.

 

[CT8]

How old are the batteries?

 

[Bear]

Thanks guys. Not sure how long it sat at the dealership but my friend bought the electric UTV last summer and was under the impression the batteries were the sealed no maintenance type.
First sign of a problem was three weeks ago but since he didn't plug it in the night before he thought that was the cause. The following week we used the vehicle again and it died mid morning, way too soon! Towed it in with one of the gas powered ATV's.
Pulled the seat to get at the battery array to look for possible causes. That's when we saw the batteries were regular lead acid ones.
Bummer, he was already told by the Polaris dealer it would be around $1200 to replace the eight batteries.

 

[Chris142]

It's been my experience that once the plates get exposed the battery is ruined.

 

[pocketchange]

Plug it back in and leave it alone for a couple of days then give it another try.
Repeat until you have given the batteries enough time for you to find someone else that sells batteries that are a touch cheaper.
Or, find a junk yard that sells used batteries.. pc

 

[69GTX]

When I bought my last used car I thought the battery was a sealed unit. 3 months after I bought it (March), it failed to start. That's when I found out it wasn't sealed, and the cells were exposed...maybe 1/2 inch or so. It took several cups or pints of water to get it back to normal. The plates were heavily sulfated. I charged the [censored] out of that battery for the next few weeks. And then put it on charge every 1-2 weeks just for good measure (the car sits for 1-2 weeks at a time).

That battery went another 3 years before the next problem surfaced, some of the gauges on the instrument panel were acting funny on startup. It was due to low voltage from sitting for a week. At that point, the battery was 6 years old. I wasn't going to risk getting stranded. I figured that was plenty good. Went to buy another Sears Die Hard Gold and found out that those are now maintenance free. I decided I liked the option of checking levels as it saved me on the last one. So I bought an AC-Delco Professional Gold instead. That battery was $25 cheaper than the Die Hard and with a better warranty.

 

[Wynn]

Here is an interesting video from Youtube on Deep cycle batteries
Making a bad 12 volt battery good again for under 5 dollars

 

[Michael_P]

I had two deep cycle / dual purpose batteries in the bed of my truck. I forgot about the batteries and took some twisty country roads with a little too much zeal. Needless to say the batteries fell over and dumped out all their acid. That afternoon, I bought some replacement acid for the batteries. Both batteries lasted less than a month and they were both two years old. I would say based on my experience and what others have said before me, your battery situation looks bleak. I would just buy new batteries.

 

[SHOZ]

You need to use a hydrometer and equalize the acid strength when fully charged and bubbling to around 1.250-1.275 specific gravity. That and when tipped over any plate material on the bottom of the cell is stirred up.

The problem with adding other acid is the unknown of the acid specific gravity spilled and state of charge for the cells.

As the cells charge the acid strength increases as the ions are shed from the plate material and attracted to the water in the electrolyte back to reform sulfuric acid, raising the sp. gr.

As a battery discharges the ions in the acid will be attracted to the plate material and be removed leaving behind water in a lower sp. gr. electrolyte.