interior LED bulb heat. issue? c30.
 

I've searched and this particular issue hasnt been discussed.

So I'm considering an interior light LED upgrade. I've read about 2 issues. 1, if they are not 'CAN BUS' ready (a silly description), they may flicker and could have a very slight dim glow when switched off.

If they are 'CAN BUS' ready, they wont have these issues.

From what I understand, interior lights on the C30 are not monitored so LEDs should be fine to work. The can bus ready ones, simply appear to have a rectifier and a resistor added to them. The issue is, from what I've seen the added resistor means additional current draw and heat generation. The T10 LED bulbs can reach 230 degrees C, as at 12v with the added 110ohm resistor they draw a lot of current.

So, here is the question, has anyone installed these and noticed them getting hot? Is there an auto electrician on here who can advise if this is an 'ignored risk' people are taking, because at 200 hundred degrees, if you leave a map bulb on accidentally, I can't imagine this is safe...

Or perhaps the interior bulbs run at lower voltage and even with LED and added resistor are still all safe.

here is a vid covering what I'm talking about.

https://youtu.be/tkPGqM0Sl64

bump, anyone?

Hi

I fitted LEDs into the interior lights on our C30 and V60, they are working fine but I have not had them in long.

As far as I can reason, the housing is designed to accomadate the heat output of the bulb, and I don't think the LED is going to put out more heat.

Do you remember where you sourced the LEDs and what brand you went for?

my concern was the 'can bus' type ones have a resistor to increase the current draw to match the halogen. However a resistor just expells the excess energy as heat. The Halogen is a combination of heat and light. So the LED resistor combo may in fact output more of the wattage as heat than the Halogen. For the smaller 2watt bulbs this probably doesn't matter, but 5 or 10 watt bulbs you are talking potentially very high temps (in theory). I was pleased you replied as it's best to find out how they are running in the real world.

cheers

While this is true, it's not the full story.

It is correct that a typical filament bulb is not very efficient and the majority of the energy (80-90%) put into the bulb is given off in heat, so an LED bulb (even with a 'CAN-BUS' resistor) will invariably produce less heat.

What is different is the distribution of that heat. A filament bulb distributes most of the heat evenly across the surface of the glass bulb which is radiated away in all directions in the same way that happens with the light it produces (as a lot of the heat energy produced is infra-red light). So the reflectors for the light, will also reflect the heat away from the parts of the bulb holder that may be damaged by it.

An LED does not have a glass bulb, and is usually built on a ceramic substrate/PCB which conducts the heat away via the bulb holder terminals. So while there is less heat produced overall, a poorly designed LED can conduct more heat to the bulb terminals than the filament bulb it replaces and can cause the terminals to overheat and melt.

To the original poster, if you're worried about whether you need a 'can-bus' LED or not, simply remove the bulb in question, and see if any warnings are generated. If there are no warnings, then you should be fine with a good quality LED without the extra resistor.

I'd be very cautious about using an LED with an extra resistor, unless you are certain that the bulb holder can handle it. I'd also be careful about the brightness of the replacement LEDs, don't get carried away thinking brighter is better. Something that is 2x or 3x the brightness level of a filament bulb will usually be fine, but the brighter the LED, the more heat is produced.

Thanks for clarifying, you confirmed what I've been thinking. It's hard to find LEDs without a resistor added from a reputable supplier. Most that are already made into a standard bulb fitting also have the resistors to match the load of an equivalent filament bulb. all seems quite daft to me. I could buy the actual LEDs and make them up on a fitment mount, but it's more hassle than I want (although it would give me peace of mind I guess).

Internal bulbs aren't monitored. Nor for that matter are number plate bulbs, tail lights and position markers.

I can confirm this, the previous owner of my C30 replaced all those bulbs for LED.

I definitely like the white light, much more modern. I had to replace one in the footwell and bought replacements from eBay, went for the CAN bus OK versions and haven't had an issue.

One thing to be careful about, measure the bulbs that come out and ensure the LED replacements fit in the bulb available space... The first replacements that I bought were too long to fit in. Schoolboy error!

:rolleyes:

I replaced all but one of the interior lights in my C70 with eBay-sourced LEDs (non-Canbus) within the first week of getting it...
....four-and-a-half years later, those bulbs are all still working perfectly without causing any issues - and contrary to some claims that the main interior light 'fade' facility won't work with LEDs, it's always worked happily...

....and the one bulb I didn't replace? In the driver's footwell, as it was an absolute pig to try and get to, so I gave up trying!

ironically leaving in one filament bulb usually makes thr whole thing work, as it adds sufficient resistance to the circuit. This is my plan so I'll do the same as it worked for you