Battery Won't charge

[Bob Foster]

Hello, I've just joined your forum in the hope of getting the solution to an irritating problem. I have an old Peljob 3 tonne digger. It has a 96Amph battery. Whenever I try to charge the battery the battery charger quickly goes to showing 100% full. It does this with two different chargers. However if I put on my Optimate smart charger which I used for my motorbikes it charges for about 36 hours before it becomes full as it is only a trickle charger. You can then tell the difference when you start the machine - it spins much more healthily.

 

[mechelec]

Duff cell in battery sounds most likely. Can you take it to an auto electrical specialist to have it load tested.

 

[Marvo]

How old is the battery? Is it a deep cycle flooded type?

36hrs to charge a battery is a ridiculously long time even with a discharge cycle thrown in first. I'm guessing the Optimate is sensing there's something hinkey with the battery and maybe running some kinda desulphating cycle. I'd take the battery to a specialist and get them to test it. They should be able to check the sg of the electrolyte and test the internal resistance of the cells under load etc.

 

[PEG]

Hi Bob,if you are constantly having to do this,either the machine is discharging the battery,or it is duff.

As suggested,drop test the battery,and check your machine for both drain and charge rate. :icon12:

 

[Des 56]

I will assume its a lead acid battery,96 amp/hr should be charged at 9.6 amp for 10 hours
Is your charger up to the task?
If the plates have taken on excessive amounts of sulpher from the electrolyte, you may need to boost charge at 96 amp at 1 hour rate to brake down the deposit on the plates
You could get yourself a hydrometer and check the specific gravity of the electrolyte

Whilst on charge use your nose to have a sniff of the cells,a faulty cell may stink quite a bit
You can voltage test each cell when off charge and on charge to monitor the expected rise
Silt can build up at the bottom of the plates and short out the cells,you could charge up the battery,pour the contents into a container,wash out the battery with distilled water then replace the electrolyte,this will sometimes revive a dead battery
There are tool box electronic simulated capacity testers that can be used to check its at least 60% efficient,load discharge testers give better results but are more specialised tools for large garages and battery service places

 

[Bob Foster]

Thank you for all the very useful replies. I'll get the battery tested, then the electrics if necessary.