Electric bike lights problem

[Peter1546]

Hi, I have a Btwin Elops 900 bike. The lights come on and off intermittently. A loose connection would obviously be first but I can’t find one and it doesn’t come on/off with a bump and even if it is on when I park up, it doesn’t necessarily come on when I switch back on. Any suggestions? Are there any capacitors/other electronics in the lighting system?
Thanks, Peter

 

[steve marino]

Electric problems are not always easy to diagnose. There shouldn't be any complicated electronics in the lighting system, those things are simply on or off. When I was turning wrenches for a living, our mantra was to ck the most obvious things first. Is it all of the lights that are going off, the front AND the back? If it's only one or the other, ck the bulb and contacts first. In any case, after you've checked that, trace the wires back to their source, which is probably a mess of wires near the controller. Turn the lights on, and if you're not sure which is which, pull each connector apart until you find the one that turns the lights on and off. Ck it and all the connectors to make sure they're clean and tight in the connections.

Then if needed, trace things to the switch itself, remembering that the switch will have a hot lead going in, and one or more going out to the lights themselves. Bang on the switch w/ the palm of your hand and see if that does anything w/ the lights switched on. Make sure everything is well grounded. I would invest $5 in a simple electrical tester from Harbor Freight. You don't need a fancy volt/ohm meter, just a screwdriver looking tester w/ a sharp point and a wire w/ an alligator clip on the end.

Watch a youtube video to see how it's done, and make sure you don't have a 12V tester w/ a 36V or more bike. Usually the voltage gets dropped from whatever the motor voltage is to something smaller for lights, but not always. A call to your manufacturer might give you info on that, or just look at the lights or bulbs themselves and ck the writing on them. Maybe buy an extra bulb for the tester just in case. The bikes are DC and nominal amp/voltage, so you don't have to worry about frying yourself like you would w/ home AC wiring.

 

[Peter1546]

Electric problems are not always easy to diagnose. There shouldn't be any complicated electronics in the lighting system, those things are simply on or off. When I was turning wrenches for a living, our mantra was to ck the most obvious things first. Is it all of the lights that are going off, the front AND the back? If it's only one or the other, ck the bulb and contacts first. In any case, after you've checked that, trace the wires back to their source, which is probably a mess of wires near the controller. Turn the lights on, and if you're not sure which is which, pull each connector apart until you find the one that turns the lights on and off. Ck it and all the connectors to make sure they're clean and tight in the connections.

Then if needed, trace things to the switch itself, remembering that the switch will have a hot lead going in, and one or more going out to the lights themselves. Bang on the switch w/ the palm of your hand and see if that does anything w/ the lights switched on. Make sure everything is well grounded. I would invest $5 in a simple electrical tester from Harbor Freight. You don't need a fancy volt/ohm meter, just a screwdriver looking tester w/ a sharp point and a wire w/ an alligator clip on the end.

Thanks for your extensive thoughts and I will certainly have a check on YouTube but unfortunately wires on my bike disappear into the frame and I haven’t had any success in getting any sort of wiring diagram from Decathlon who supplied the bike. Have to say that in general I’ve been delighted with the bike - not an expensive one as electric bikes go - had it 3years and done 4K miles without other issues.
Peter