Testing For A Bad Cell - 36v Front Wheel kit

[flat6valk]

Greetings,

I have 3 brand new 12v 12ah SLA batteries, and even after a full charge they appear to cutoff way too early. I don't seem to be able to go more than a few km (at top speed mind you) before the indicator LED's start to drop from 2 green to one green while under load. I'd estimate around 8 - 10 km (flat terrain, 190lb rider, no pedaling) it begins to cutout under load. The battery pack shows 41.9v after charging with no load.

What is the proper way to test for a bad cell?

Thanks.

[myelectricbike]

New SLA batteries do require some conditioning but even after conditioning there remain many factors which can reduce range besides those you have listed.

The easiest way to load test a battery is with a 1 to 2 amp 12 volt auto turn signal bulb or the equivalent and a volt meter, preferably one that is linked to a PC for automatic recording of voltage. If you have a dead cell then it will usually appear as a rapid drop from 12 volts to 10.5 volts within minutes within 1 or 2, maybe 3 hours whereas if the cells are good it should take up to 20 hours depending on the exact resistance of the bulb after it is burning. Bad cell - fast drop off to 10.5 volts. All cells good - wait is usually longer than 5 or 10 hours with slow gradual drop off.