LED Lights Glowing When Off

[Basil]

Hi All, thought I was being sensible changing our PVC auto interior 'door' lights from the normal capless 10Watt 501s to 1Watt LEDs, as it is quite nice to have the interior lights come on when you open the doors on return at night but don't like the thought of the drain on the vehicle battery, 3x10 Watt a 30 Watt drain although for a short period!

Anyhow after changing the bulbs they come on when the switch is on and go completely off when the switch is off however when the switch is in the 'Auto' position the lights stay on until the time delay shuts off then go to a very small glow. searching the net comes up with loads of information suggesting this is a common problem and giving the 'cure' as installing a resistor in parallel with the bulb connections but doesn't this mean the small current is still there?.

 

Now whilst the resistor may stop the glow I am wondering if this could be the cause of some people having battery drain problems when left parked up as this 'leak' of electricity is not apparent when the normal incandescent lights are used. To my mind this must be continually draining the battery, if only by a tiny amount, over time surely this must have an effect.

 

I guess that is my question to anyone who has any knowledge, first why is there a current 'leak' in the first place and would putting the resistor in be a satisfactory cure or will there be a continuous drain on the battery. Please discuss thank you!

 

Basil

[colin]

I'm not sure how your lights are wired, but this is a common problem with many LED and CFL lights in an electonic circuit, but I believe it's no more power used than with Incandescent, it's just that the current is enough to illuminate the 'bulb', whereas with an incandescent the current flowing is not enough to make the filament glow.

[BKen1]

As LEDs are polarity sensitive I would try swapping the lamp round in the fitting before getting involved in fitting resistances.

 

 

Brian K

[Basil]

Thanks for the reply's Colin and Brian.

 

The wiring is the standard car manufacturers system for the interior lights with time delay, all I have done is to change the bulb from a standard cap less type 501 bulb to an LED equivalent. The switch on the interior light is a three position off/on/ auto switch built into the light as on most vehicles. The problem is only in the auto position where the light powers down a period of time after closing the door, or immediately on locking the vehicle.

 

This was my point about there being no more current than the normal bulb but surely there should be no current at all else surely that means that there is a drain even though it cannot be seen with a normal bulb?

 

I understand the polarity issue with LED but this isn't the cause of the problem as the LED simply does not work if plugged in the wrong way round. This problem occurs in the auto position where the LED is picking up some current after the power down of the vehicles door and locking system.

 

Basil

[Charles]

Don't worry about the current drain Basil, it will be micro amps and would still be there if the old bulbs were in.

It's a leakage current because the transistor that dims the bulb isn't fully turned off.

[Muswell]

We had that problem in a dimmable domestic circuit and instead of putting in a resistor I just swapped one of the lamps for a normal GU10, as recommended by the switchgear technical support. That also reduced the flicker, which is a problem with dimmable LEDs

[StuartO]

It may be that the delay circuit was designed to control ordinary halogen lamps rather than LEDs and if there was no sign of significant battery drain before the LEDs were installed (and since they only illuminate for a short period so cannot consume much electricity anyway) the simplest remedy would be to reinstall halogen units.