LED interior lighting blowing 5A fuses [Resolved]

[willythepooh]

I have 4 main LEDs, two touch sensitive LEDs (all 70mm), two reading lights and all test OK with a 9V battery.
If I connect up through a fuse box and supply 12V from the leisure battery, they just blow 5amp fuses. Anyone have an idea ? I’m at a loss with this one.

 

[Pauly]

I seriously doubt they will draw more than 5amps unless they are very powerful
As an easy test You could try disconnecting a couple of them to prove one way or the other or you could disconnect all four and energise the cabling and see if it still blows ie a short in the cabling ?

 

[Murdoch]

Start up current ?

 

[Salty Spuds]

I have 4 main LEDs, two touch sensitive LEDs (all 70mm), two reading lights and all test OK with a 9V battery.
If I connect up through a fuse box and supply 12V from the leisure battery, they just blow 5amp fuses. Anyone have an idea ? I’m at a loss with this one.

Have they ever worked correctly or is this a new installation?

 

[willythepooh]

I tested each one using a PP3 9volt battery to make sure they worked, both installing and after installation.
seems very strange that as soon as I wire up to the fuse box, and apply 12volts the fuses blow.
I have noticed that the main 4 downlighters glow dimly ( as if they have about 3 volts ) when the fuses have blown.

Have they ever worked correctly or is this a new installation?

new installation. Constructed the ceiling wired it all up, tested it, then this.

 

[T6Jay]

Are the casings supposed to be isolated from bodywork in order for the touch sense to work?

 

[Salty Spuds]

I tested each one using a PP3 9volt battery to make sure they worked, both installing and after installation.
seems very strange that as soon as I wire up to the fuse box, and apply 12volts the fuses blow.
I have noticed that the main 4 downlighters glow dimly ( as if they have about 3 volts ) when the fuses have blown.

new installation. Constructed the ceiling wired it all up, tested it, then this.

Are they wired correctly? I.e. +ve & -ve the right way around. Some LEDs will short circuit if reversed polarity.

 

[VW camper]

Possibly the fuse is shit... cheap knock offs. But I'd go with that last.

 

[willythepooh]

Are the casings supposed to be isolated from bodywork in order for the touch sense to work?

I’ll look into that one. They work with a voltage to them. 0V and 12V.
sitting in a piece of ply.

 

[DXX]

Could it be the wiring? Too small cross section or excessive length will cause an excessive DC voltage drop and increase the current drawn. You could try measuring the voltage at the lamp socket

 

[willythepooh]

The wires do the usual route from driver’s seat, up the B pillar, along the roof line.

 

[DXX]

The wires do the usual route from driver’s seat, up the B pillar, along the roof line.

If you measure the actual voltage at the socket you’ll find out if there is a significant voltage drop.

 

[mmi]

I have 4 main LEDs, two touch sensitive LEDs (all 70mm), two reading lights and all test OK with a 9V battery.
If I connect up through a fuse box and supply 12V from the leisure battery, they just blow 5amp fuses. Anyone have an idea ? I’m at a loss with this one.

By any chance the LEDs are "raw" LEDs - which should be used only with a dedicated power supply (=current limiter) aka "LED driver"
Inherently current draw of "raw" LEDs grows exponentially with voltage - thus testing with 9 Volts battery (which has low current output) would work.

 

[Salty Spuds]

Could it be the wiring? Too small cross section or excessive length will cause an excessive DC voltage drop and increase the current drawn. You could try measuring the voltage at the lamp socket

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

 

[willythepooh]

By any chance the LEDs are "raw" LEDs - which should be used only with a dedicated power supply (=current limiter) aka "LED driver"
Inherently current draw of "raw" LEDs grows exponentially with voltage - thus testing with 9 Volts battery (which has low current output) would work.

This is what I ordered originally from Megavanmats.
Black 12v LED Flexi Reading Light Without USB	2
Touch Sensitive LED Light - Recessed Fitting	2
LED Light - 7198CW: Cool White	4
CBE Double USB Socket	1
CBE Double Switch - Raised 272082PK

 

[Salty Spuds]

Is it any of the lights that blows the fuse, a certain combination or just specific ones?
Or does the fuse blow as soon as the whole circuit is connected to the van, regardless of whether the lights are on or off?

 

[willythepooh]

I’m just going to find out.
the 4 main ones should only draw 0.6 amp, if I assume 1.8 W each. I’ll check between all the pos and negs for continuity also.

 

[mmi]

This is what I ordered originally from Megavanmats.
Black 12v LED Flexi Reading Light Without USB	2
Touch Sensitive LED Light - Recessed Fitting	2
LED Light - 7198CW: Cool White	4
CBE Double USB Socket	1
CBE Double Switch - Raised 272082PK

Touch Sensitive LED Light - Recessed Fitting
They are suitable for use in motorhomes, campervans, caravans, van conversions etc as they are 12 volt D.C. and dont require a driver.

Probably this one LED Light - 7180 Warm or Cool White
Couldn't find the exact type 7198CW (except the one inside the web address above "/led-light-7198cw/") - however, a bit vague statement in there (product information)...

LED Light - 7180 Warm or Cool White
Requires 12vdc LED power supply

Interestingly they do not sell LED drivers and even more interestingly on their front page there is a statement: "All of the lights we offer are designed specifically to be used with 12v DC."

 

[willythepooh]

The touch sensitive lights (x2) are working.
The reading lights blow a fuse as soon as I turn them on.
I suspect the main (x4) will do so also.
Just getting another fuse

 

[willythepooh]

Sure enough - fuse blown.