12v led's

[norseman]

I'm planning to replace the standard festoon interior bulbs with LED items. On the basis that these bulbs are brighter than incandescent ones, any idea of the wattage required to equal the original 21w & can the LED's be used as a straightforward replacement?

Thanks in advance folks.

 

[Burnerman]

You can use the LED bulbs here, no problem....it's really the physical size that determines things.
LEDs can cause problems with your indicators though, if it's not designed for them. The lack of current draw upsets the flasher relay.
John

 

[DaveHerns]

21w festoon bulbs? I'd haver thought more like 5 or 6 watt . My experiences with LED replacements for 5w wedge base bulbs has been bad , poor light and short life.

 

[stuartb3502]

I just replaced some festoons in my boot and engine compartment with LEDs. The LEDs I bought are not as bright so I would not recommend. They also have chunky heatsinks on the back so can be a tight fit. To give you some context, the ones I got were on Amazon "MIHAZ 10x 39mm 4SMD White 6000K". Looking for something better now. In my case there are replacement LED light units available (i.e. not just bulbs) so may try those.

 

[DaveHerns]

I've just fitted some 39mm CANBUS festoon bulbs in my rear number plate light and they're excellent. Nice white light. 6 led's facing downwards , just as needed.

 

[norseman]

Update : Finally fitted 39mm LEDs into my interior lights, what a difference to the original yellow glow! The only thing I did notice is that the LEDs need to be a good fit in the lamp whereas the incandescent festoons would work even if they were a sloppy fit between the brass contacts.

 

[DaveHerns]

I told fibs. I should have got 38 or 39 mm LEDs but I mismeasured and bought 36mm's. Bent the legs of the fitting in and they haven't fallen out yet. Now I want some 501 wedge base LEDs for the interior lights and I assume they don't need to be CANBUS?

 

[norseman]

I told fibs. I should have got 38 or 39 mm LEDs but I mismeasured and bought 36mm's. Bent the legs of the fitting in and they haven't fallen out yet. Now I want some 501 wedge base LEDs for the interior lights and I assume they don't need to be CANBUS?

I confess to doing exactly the same thing, measuring between the contacts without noticing that they had already been bent in order to fit existing festoons! Consequently the first pair of LEDs fitted like a p...k in a bucket so I bent the contacts & re-ordered 39mm, job done!
I don't know what canbus means but suspect it's somehow connected with modern vehicle electrics ? My car is 30 years old - hopefully someone on here can come up with an explanation.

 

[JohnD]

I'm not going to look up CANBUS but my car uses it to detect if a bulb has blown. The LEDs use less current than original filament bulbs, so some are made to replicate the characteristics of a filament bulb so the car doesn't think they've failed.

I noticed when I changed a rear lamp cluster that it had a little PCB in it.

edit
here you are https://en.wikipedia.org/wiki/CAN_bus

 

[norseman]

I'm not going to look up CANBUS but my car uses it to detect if a bulb has blown. The LEDs use less current than original filament bulbs, so some are made to replicate the characteristics of a filament bulb so the car doesn't think they've failed.

I noticed when I changed a rear lamp cluster that it had a little PCB in it.

edit
here you are https://en.wikipedia.org/wiki/CAN_bus

That explains it, thank you. I'll have to remember that should I think about changing the festoons in our daily driver that is (only) 11 years old!