Motor cuts out issue

[hotdiggity]

With the battery charged and the system switched on, the battery level indicator on the handlebars displays all three lights - min, med and max. After applying the throttle grip the motor engages but cuts out after only 1 or 2 seconds (varies). The battery indicator glows and fades on "min". The system then needs to be switched off and on again to get the same result. When the back wheel is lifted off the ground and the throttle applied, ie. without a load on the bicycle, the motor doesn't cut out at all but keeps spinning with all three battery lights on. Any ideas out there please as to how to solve this issue?

[KenGS]

Get a new battery?

[Joeblake]

Yes, sounds very much like a battery issue. Cheapest option is to see if you can borrow a replacement battery for a couple of minutes and try the same thing. If it runs okay, there's the likely suspect.

I guess the next questions are (a) how old is the battery, (b) what type eg lead-acid NiMH, NiCad, (c) how often/much do you ride the bike?

Joe

[r2160]

A battery can show good voltage, but have no capacity (current) to use once a load is applied to the motor.

the best thing to do is check that it is charging correctly first, and if this is OK, have the battery checked

cheers
Glenn

[nessbike]

I concur with other respondees - had a similar problem with a bike recently. Swapping out the battery (after checking all connections and possible brake cutout issues) solved the problem. I suspect it may have been a dud cell as the original battery was new, but difficult to check without stipping the battery down. cheers Alex

[cachexian]

Agreed with other responders.

The three lights are a crude measurement of voltage.
Here's what I think is happening:
When you are applying load to the motor (i.e. sitting on the bike) the controller is trying to take a lot of amps from your battery. This is causing the battery voltage to sag. It's sagging below the "low voltage cut off point" of your controller that then switches off to protect the battery.

Get a new battery and all will be well.

C

[cachexian]

Need a battery charger
by hotdiggity » Wed Feb 22, 2012 9:11 pm

Trying to buy on a charger for an unbranded ebike battery. It's a 35 volt battery, most probably Li-ion. I was recommended a 1.5 - 2 amp charger by the local ebike shop, however the chargers online mostly specify amp hours (10 or 12). Any clues?

Is this still the same battery for which you bought the charger? How did you end up charging it? Happy to have a look at it for you if you're in sydney but also you could go to glowworm bikes.

You might be better off having your motor and controller identified and getting a whole new battery and matched charger made up for you. Hyena Industries will make you up a lightweight battery and charger that will not sag under load and will be a better battery than you started with...

C