Battery electrolyte escaped whilst charging.....!
 

OK, not a 75/ZT battery, but I would be very grateful for any assistance:bowdown:

I have a traditional maintenance-type battery with caps/vents (Enduroline brand), purchased 2013. Used regularly for some weeks/months at a time, and then not used for several months, but put on charge every so often.

At one point it did get knocked over and some acid came out (exit one Haynes manual and an old pair of shoes!), topped up, seemed OK, used daily for a few weeks last summer, all OK. It may have stood for a while after unused and possibly gone flat, but has been charged since.

I use an automatic battery charger, charges at 3.6amps then drops to trickle at 0.8amps.

At times the battery is left on the charger for several days at a time - as it drops to trickle charge I assume this is OK.

A month or so ago, the battery had been on charge for a few days. A few days, or maybe a couple of weeks later I put it on charge again.

The problem: After less than an hour on charge, I noticed a small amount of electrolyte had bubbled up out of the vent cap on the second cell to the left of the positive terminal. I took it off charge immediately and haven't touched it since.

Can anybody please tell me why this happened and if it is safe to just check/top up the electrolyte levels, charge and continue to use it?

I haven't come across this before and I do not know what is safe to do next. Advice appreciated.

Regards, Bolin.

Check the battery is still all square and one of the cells hasn't blown, bulging.

The problem with chargers that trickle charge at 0.8A is that they are still overcharging and therefore overheating the battery if left on for extended periods. I expect that is what is happening with your battery based on your description of the charger.

Maintenance chargers actually stop charging once the fully charged state is achieved and then check constantly until a top-up charge is needed.

Battery looked OK, not seriously warped or anything.

I had put another battery on charge, which was definitely past it's sell by date and good only for running electrical systems but not cranking, and found that I could hear it bubbling way! I think the charger is faulty and continuing to charge when it should switch to trickle.

I cleaned the first battery, checked the electrolyte levels and they were fine, voltage was 12.6v (this being a couple of weeks or so since it leaked). Tried it on the car - cranked slowly but did crank, but cranking got too slow after a while (engine not starting). Will try charging with a different charger and see how it goes...

What did you top it up with?


TC

Distilled water.

I'm not a battery expert but isn't there a risk of explosion fire to constant charging due to gasses that are produced in these types of batteries?

There is that risk with all lead acid batteries. The gas produced (Browns Gas) is extremely explosive - a perfect mix of oxygen and hydrogen, ready to to combine to water. An additional risk is that of the exploding battery spraying its acid around the area - it just needs a tiny spark.



If any (one or more) cell is gassing, it suggests the battery needs to be replaced. It indicates that the heavily gassing cells are faulty. Once off charge and a brief load applied, the voltage will decline rapidly. Once left for any length of time in a discharged state, the battery will be unlikely to recover.



I have many lead acid batteries and I have ruined a few in the past, relying on 'maintenance chargers' connected long term. My regime now is to connect them for sufficient time to fully charge a low battery, but never longer than 48 hours. I then give each a boost charge every 2 or 3 months.


I have my caravan on 240v, in the drive, with its 13.8v on. I used to leave the battery connected to the 13.8v to keep it maintained, but lost several sealed batteries due to them drying out. Now my regime is one of not leaving them connected, my present 110ah battery is good as new five years down the line.

I don't know if this explains your situation, but using DI water to top up a battery that's had an acid spill will dilute the electrolyte to a lower density than it was before. This may have an effect on the charging. It really depnds on how much was spilled. Lost electrolyte should be replaced using sulphuric acid of the same strength. Normal DI water top-ups simply replace water lost from the solution by evaporation.



TC

Thanks folks, I now know how better to look after these batteries which are not in regular use.

The battery was tried a day or two later, cranked OKish but car didn't start, then at second attempt car did start and was run for 20 minutes or so. I might be lucky and get some more life out of it yet, fingers crossed.

Well, it is hard to give a volume, but the plates were visible in at least some of the cells, but the level in those cells was not far below the tops of the plates. So not a huge amount of water was added.

Also important to note that the car has always been a bit slow at cranking, whatever battery is fitted (not sure but I suspect there were issues in the car's past as it had a couple of replacement alternators and an ammeter fitted when I first got it, it was never run before a different main loom was fitted for unrelated reasons). Next step for investigation is the starter motor, appears to be totally original (40 years old) - I think I did try a different one which was a bit better.

So I think the next step is to fully charge the battery and take it off charge as soon as it is full, and check/top up the electrolyte if required (might not be).