Running tests on a battery, when is it stuffed?

Millie Master

Full Member
I am currently running some tests on one of my leisure batteries as it is now 5 years old.

The battery is now fully disconnected and using my voltmeter I am doing daily tests so that I can watch for voltage drop and it appears that it is loosing approx. .4 of a volt per day.................................. is it stuffed or does it simply need to be run through an extensive discharge/charge charging cycle programme?



Full Member
0.4V a day disconnected is a lot to drop.
I would be inclined to do a discharge under load until the battery is down to under 11V and then using the charger do a full recondition/equalize at high voltage (typically around 15.5V) to try and desulfate the plates. Maybe repeat a couple of times. Might work.


Full Member
You must charge at 14.4 then rest to 12.7,then a heavy load test to see how long it will hold before dropping to 12.2 after a rest,we used to have a tool for this in the trade which was tongs with a resister coil between and a meter.
Here is the same thing in new cloths
battery load tester.png


Full Member
If your interested in it's useful capacity Phil, a simple test is to connect a 21watt bulb across it and watch the volts drop. If a 21watt drain is not close to your average usage, just a add or remove bulbs to suit. It doesn't take much calculation to work out it's new capacity.