Kalkhoff 18Ah battery discharging - is it faulty?

[MGR1]

Hi all.

My 18Ah Kalkhoff battery suddenly started to discharge itself during periods when the bike is not in use (battery is left on bike). Within one week it can go from 5 bars / leds to 1, or from 4 to 1 blinking. It has not done this before. I am dismayed . Can I assume the battery is faulty? Is this a common failure mode?

Bike and battery is only one and a half years old, and has done only 1280 km's in total. Are there any checks I can do? Any help would be appreciated.

 

[banbury frank]

Hi

I would take the battery off the bike and fully charge it the see if the sane problem happens it will then isolate the problem to the battery or the bikes electronics

Frank

 

[Deleted member 4366]

Are you sure that your partner or one of you kids isn't nippimg out on it when you're not looking? I think this is the most common cause of battery going down unexpectedly.

 

[Blew it]

...Can I assume the battery is faulty? Is this a common failure mode?

Yes, although not common considering the number of these batteries in use. Yours is the third example of this type of failure that I am aware of.

In the case of my own battery, when removing the battery from the charging dock, the battery LED's remained lit. Over a period of a week, the LED's went out one-by-one until it was completely flat. This is most likely due to the internal Battery Management System failing. My battery was returned to the supplier and replaced under warranty.

I believe BMZ give a two year warranty on their batteries, so I would suggest you approach the retailer and have the faulty battery replaced. There are no user serviceable components inside the battery

 

[MGR1]

Are you sure that your partner or one of you kids isn't nippimg out on it when you're not looking? I think this is the most common cause of battery going down unexpectedly.

I wish that would be case, unfortunately the kid is too small and wife shows no interest in biking. And it's locked and I have the key.

 

[MGR1]

I will do some testing off-bike as suggested, to isolate the problem. I bought the Kalkhoff second hand, from a gentleman that bought it in Flensburg in Germany. I have the warranty card, but haven't checked the warranty details yet. Hopefully it will cover battery problems within two years from purchase even if I am not the original buyer.