Battery Charging Issues

[stevd]

Hey,

Looking for some help regarding batteries. Its not something I know a huge amount on.

I have two wet batteries, one battery for leisure use, one for engine starting.

I have a sterling mains battery charger. Whilst on charge, the voltage accross the batteries is 12.77v which seems a little low to me whilst on charge, should they be high end 13 volts low 14 volts? I am struggling to get a charge into the batteries, it takes ages where it used to be very quick. When taken off charge they have around 11.8 volts. But I havent been able to get much charge in.

The batteries haven't been holding a charge very well lately.

Whilst on charge, two of the 6 cells on the engine battery fizz away, whilst the other cells, including the leisure battery dont.

There is an in line fuse from the charger. This can get very warm! worryingly warm. But the fuse doesnt pop. its a 20amp fuse.

Are my batteries knackered, or is the charger gone.

I dont know how old the batteries are.

I am happy to replace them, but my concern is that there might be damaged by the sterling charger, in which case I dont want to fork out on some expensive batteries just for them to be ruined within a couple of cycles. Mind you I guess they would be under warranty.

I have also recently refitted my engine, I dont think this has anything to do with it, as I noticed just before I refitted the engine the batteries werent holding much of a charge, but thought I would put it out there anyway.

Any advice.

Cheers

 

[RAI]

Sounds like dead batteries. A hydrometer will tell you which cells are dead.

 

[stevd]

Does it sound like both batteries are dead? Hydrometer, like the one I have for testing alcohol content for my homebrew?

 

[RAI]

Does it sound like both batteries are dead? Hydrometer, like the one I have for testing alcohol content for my homebrew?

You could try disconnecting the batteries and charging them separately. It sounds like at least the engine battery is dead, the other one might recover from being dragged down by it.
You need a battery hydrometer, same principle, different scale I'd guess. The battery one is looking for specific gravities in the 1.2 to 1.3 region.

 

[Stemar]

I'm not sure that you need an hydrometer to know that a battery with a couple of fizzing cells is dead.

For me, step 1 would be to measure the voltage drop across the fuse. If it's more than a few tenths of a volt, clean the contacts, because the heat's at least partly due to high resistance where it shouldn't be.

Step 2 would be to disconnect the engine battery and see what happens when I charge the domestic one on its own. If it charges and holds the charge, you've got away with that one for now. If not, step 3 applies to both batteries.

Step 3 would be to replace the engine battery, cos it's knackered.

If all else fails, I'd be looking at the charger but, before I spend big bucks on a clever mains charger, I'd consider whether I could fit enough solar panels to meet my needs and get a cheap and cheerful charger for the odd times in winter when the panels can't keep up from one weekend to the next. Obviously, if you live aboard, that's a different calculation.

 

[nigelmercier]

... Hydrometer, like the one I have for testing alcohol content for my homebrew?

Same idea, but designed for batteries: http://amzn.to/1gl17Wq

 

[NickRobinson]

You don't mention whether either battery actually can start the engine?

Your thought.... 'Mind you I guess they would be under warranty.' is not a good idea, battery warranties are famously full of caveats and unenforceable even without you confessing publicly to ill-treatment....

N