Running a light off my e-bike


brr, summer's over
My Carrera has a nice USB port on the controller unit.


Is it possible to run a light off this, preferably a Cree type and do away with charging batteries?

If so, does anyone have any recommendations?


Legendary Member
I don't think you can. I think its merely a diagnostics port.
I wanted to do the same but unless I mis-read something...its a no.


North Wales
I wanted a rear lamp that would fit on a cycle rack, only one in stock at local shop was USB charged, however it kept going flat, so I thought easy use one of these batteries for recharging phone would extend the time, however it did not work, while on charge you can't turn it on, shop swapped it and new once lasts long enough it was clearly faulty.

It actually looks the same as fitted to electric bike, however instructions for electric bike say the built in lights should continue to work for an hour after it has stopped working the motor, so clearly all built into the bike which has a Bosch motor.


My Giant Fastroad e has a micro charging port on the display unit. They supply a lead too. Took a long read of the handbook to find out though nd the charging rate.


Active Member
If you can charge a phone from it you should be able to run LED lights off it if you can do the wiring.

On my non-electric all weather all seasons commuter I run permanently-mounted LED dynamo lights off a USB battery pack which I charge in situ once a week (but it actually lasts much longer, I often forget!). USB is 5 volts but dynamo is 6 volts, but they work great.

I did the wiring by taking a phone charging cable, cutting the phone end plug off and stripping back the outer insulation. Of the many wires inside I assumed red and black were + and - power, and cut pff the rest. I wired the power to the front light which also has connection for the rear light so that the front switch also switches the rear.

Has been working great for a couple of years now.
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