How to check a SMF battery , whether its good or not ?

Hello every one . I have built a E-Bike . there are two 12V 12Ah batteries. the total current taken from the batteries is about 11-12 Amps. i purchased two exide EP - 12-12 battries. but after 6 months one of the batteries is dropping the voltage to about 11V . I gave the battery for the replacement but company gave it back telling that the battery is allright. Actually after full charge , the voltage is 13.8V but after putting the load , it drops to 11V . Pls anyone tell what to do, is the battery allright? or i need to change it?

Samiran2 years ago

during load operation due to high current drawn , the voltage may seems low. Isolate the battery and then measure its voltage. Typically a fully charged battery will show some more volts than its ratted for.

---- Best wishes