LED interior lighting blowing 5A fuses [Resolved]

[Phil_G]

Volt drop would reduce the current, according to Mr Ohm.

Mr Ohm was talking about a straight resistive circuit. Low voltage to a switchmode regulator (as most LED PSUs are) will increase the current as it tries to maintain its output

 

[willythepooh]

What are you telling me ?
V=IR
W=VA
What else is there ?
Just spoke to Megavanmats and he says no driver needed.
I have a problem !

 

[mmi]

Well, if you want to experiment - connect a regular H4 bulb (or similar - 55 W) in series with the LED. The 5 Amp fuse has no problem handling this but you'll get very bright and very hot LED light for a second. Certainly would be safer to start with a smaller bulb.

 

[Phil_G]

What else is there?

What else is there? where do I start....

But back to the OP, if the lights glow dimly when the fuse is removed, then you have a wiring problem, that voltage is coming from somewhere other than via the absent fuse. When you replace the fuse, that feed is battling 'whatever the dim source is'. With the fuse removed, the entire lighting setup should drop to zero volts as 'chassis' is its only remaining connection (assuming chassis is common and its a switched positive supply)

 

[Salty Spuds]

Mr Ohm was talking about a straight resistive circuit. Low voltage to a switchmode regulator (as most LED PSUs are) will increase the current as it tries to maintain its output

Ahh! I was just responding to the volt drop= increased current bit. Nobody mentioned electrickery. I’m guessing that the OPs 12v LEDs will be a simple LED array with a current limiting resistor in series. Of course I may be wrong.

 

[Phil_G]

Higher power leds rarely use a simple ballast resistor, its usually a constant-current regulator of some sort.
On '12v' led lights the reg is inside the housing. This is why most are not readily 'dimmable' by pwm

 

[Sim60]

Draw us a diagram - you have reading lights and main( x4) all connected in parallel ? and it's all your own wiring? or are you reusing some of the internal light wiring that comes with the van?

Simon

 

[willythepooh]

OK, here’s an update.
I took out the switches and using my multimeter found that the common ( or so I thought ) connected to the O/P live.
3 connections, not possible !
I’ve wired the 0V together on three switches and connected the live to the switches. All good now, just need some more fuses.
Thanks guys for your help and I’m glad I didn’t rip the ceiling off.

 

[VW camper]

Disconnect all lights from switches and bell out cables, you could simply have a short circuit on one feed. I bet it's this. Or a mix up of neutrals and lives