LED light question

[S2r]

We've got a new LED brake light / tail light unit for the son's moped that we're looking to fit it but have come up against a bit of a puzzle.

When the bike's not running it works fine but when it's running the lights don't work at all - I've checked the voltage when running it's putting out 13-14v through the lights so was wondering if this could this be the issue. If it is, then could it be sorted with a 12v resistor on the earth?

If it isn't this, what else could it be?

[Penelope Stopit]

S2r said:

We've got a new LED brake light / tail light unit for the son's moped that we're looking to fit it but have come up against a bit of a puzzle.

When the bike's not running it works fine but when it's running the lights don't work at all - I've checked the voltage when running it's putting out 13-14v through the lights so was wondering if this could this be the issue. If it is, then could it be sorted with a 12v resistor on the earth?

If it isn't this, what else could it be?

The lamp LED's will have built in resistors so that they will run on 12 volts without quickly burning out. voltage going up to 14 volts when charging isn't a problem, the LED's will brighten a little

Faulty lamp?

[NMNeil]

Check the output voltage on the AC setting. If you have a voltage it means that the rectification is poor, a known problem with moped charging systems.
The LED may be on but very dim as it's only getting part of the DC output.