Hi guys,
A friends built a kit car and has come to me with a issuse. He's wired in some fancy green LED lights he has a 4 blade fuse box for live and has ground the negative to the car, they work perfect until he starts the car and the alternator kicks in then the fuse blows.

But obviously a alternator kicks out around 14.7v so it must be surging the LED lights and popping the fuse. My soulation is to make or buy something that has a something like a 10-32v input but a regulated out put of 12v 10a, I can't find anything or think of how to make it... any pointers or ideas ???

My theory is the LED lights has no circuitory to it what so ever so when the car fires up the LEDs try to draw way too much so pops the fuse. The LEDs just just a metal plate with a + and - that's it.

Thanks
Josh

 

Not likely with the information given..

Can you provide information on this "fancy green LED light"?

I'd guess its just an LED with a resistor.. Overvoltage would just cause more current to go through the LED but should not cause a short that blows a fuse..
Do the LEDs survive (aka work again after the fuse is replaced)?

But even without a resistor the LED would just typically burn out (quick flash of light and gone) and not pop a fuse..

 

It's same as this but green https://www.ebay.co.uk/itm/172359171337

There's nothing in it just the led strip with + and - the light sits on all day happily until you start the car and pops the fuse, renew the fuse and it works again until you start the car. The fuse box goes directly to the battery and it's a bus bar type like this https://www.ebay.co.uk/itm/321498827057 then it's earthed to the frame work of the kit car for the negative I've wondered if that's a issue too, I've always bought LEDs with a wiring loom which includes a in line fuse, switch etc.

Thanks
Josh

 

How many lights are fitted and what rating is the fuse?

"NOTE: Cannot be used for the cars of German Brand."
I have no idea what it is about German cars that would affect these lights.