Can I test if my battery is faulty and if so how?

[Mrke]

Hello,


Not been on here you ages and ages but now I have a question please....


I think the battery has failed on my bike and I'd like to know the best way to test and then if faulty to repair or replace. Hopefully someone here can help with some wisdom and advice?


Charger charges the battery; red light while charging and then goes green once charged.


Bike then works and shows full charge and gives power at the three levels offered. The battery level quickly drops from 5 to 4 lights (3 minutes or so) and then shortly after the power cuts out completely and the display goes blank. Recharge the battery and then repeat with the same outcome....

I've tried removing and reseated the battery.


Bike is a Cyclamatic CX1 PowerPlus of 2017 vintage. 36V, 250W, 8.8kW downtube battery.


Little use over the years, hundreds rather than thousands of miles in total over that time.

Thanks,
Mark

 

[Nealh]

A few basic checks:
Double check the charger output is 42v with a meter reading.
Charge the battery till light goes green then check the battery voltage soon after charging and a few hours later at rest, one should see approx. 42v or near as damn it.
Anything less like < 41v indicates a cell issue which may mean opening th battery for further voltage readings.

 

[Mrke]

Will do, thanks very much

A few basic checks:
Double check the charger output is 42v with a meter reading.
Charge the battery till light goes green then check the battery voltage soon after charging and a few hours later at rest, one should see approx. 42v or near as damn it.
Anything less like < 41v indicates a cell issue which may mean opening th battery for further voltage readings.

 

[saneagle]

You can do the measurement that Neal suggests, which will give some indication of problems, but I think it’s just going to confirm what's pretty obvious that your battery is either out of balance or knackered.

The only thing you can do is put it on charge for 12 hours to see if it improves. If it does improve, repeat until it stops improving, then judge whether it's good enough. If it doesn't improve, it's knackered. From the symptoms you describe, there's no type of failure in your battery that would be easily fixable other than by this method, so you might as well do it first.