Smart Car of America Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
861 Posts
Discussion Starter #1
i stopped at a surplus store yesterday and was hunting around and found an led dome lite bulb. got home and put it in. went out in the wee hours to see what it looked like and found it had a faint glow. guess some juice was leaking into it. since it wouldn't lite up when the door was opened i took it out. at 2.50 i thought i had a better deal than diode dynamics.

phooey!
 

·
Premium Member
Joined
·
11,309 Posts
depends on what the bulb was made for. it could have been for a 24 volt system, or maybe it is defective,or maybe designed for ac system.

Buying from Diode Dynamics you will get the correct one for your application.
 

·
Registered
Joined
·
729 Posts
I've tried several different LEDs without success. They all seem to stay lit just a little since there is always some residual current going to the dome light.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
333 Posts
Here you go, 2 for $0.99, shipping included!

2Pcs High Quality 36mm Festoon COB 12 Chips DC 12V LED Car Dome Reading Lights | eBay

They are BRIGHT! Powering it up on the bench it is difficult to look at.

I bought 2 sets of these for my 451, one in each license plate light and one in the dome light. The dim glow when off is common and I think everyone here using an LED dome light has it. I'm not sure what sort of driver circuit smart uses for the dome light, or why they chose to implement it like this... but it is the nature of the beast.

~toaster
 

·
Registered
Joined
·
271 Posts
My LED dome light glows when off, so I turn the switch to "off". I rarely drive at night and if I do, I can switch it on again. The bright, pure white light it makes is very impressive!
 

·
Registered
Joined
·
861 Posts
Discussion Starter #7
guess i will stick with the stock bulb as i would like to have some light when i open the door. the led i had was automotive and when the switch was in the door position it was dim all the time even when the door opened up. i don't feel like having to flip the switch on for the reading light then turn it off when i get situtated in the car.

now if it was dim all the time but lit up when the door was opened i could live with that (ain't gonna hurt the battery one bit).

does the $.99 bulb function that way?
 

·
Registered
Joined
·
729 Posts
Mine would light up bright when the door was open, but glowed dimly when door was closed.


Sent from my iPhone using Tapatalk
 

·
Super Moderator
Joined
·
17,480 Posts
As part of my LED headlamp project I found the solution to LED licence plate lights that blow after just a couple months and LED dome lights that glow when turned off.

For license plate lights: Get a CREE LED festoon bulb with a CANBUS chip. They're easily identifiable as having heat sink fins on the back of the enclosure.



For dome lights: Get a festoon LED bulb with a CANBUS chip. Most eBay sellers lie about their LEDs having CANBUS chips, so be careful here. If the CANBUS chip is nonexistent or doesn't have a high enough resistance, the dome light will stay on when turned off.

Most good CANBUS festoons look like that CREE festoon above, but with normal LEDs.



To be honest, I'd just recommend getting the dome light as a CREE festoon with a CANBUS. It'll make your dome light amazingly useful.

My golden rule of buying LEDs: If they're dirt cheap, chances are they aren't going to work or not going to last.
 

·
Registered
Joined
·
333 Posts
guess i will stick with the stock bulb as i would like to have some light when i open the door. the led i had was automotive and when the switch was in the door position it was dim all the time even when the door opened up. i don't feel like having to flip the switch on for the reading light then turn it off when i get situtated in the car.

now if it was dim all the time but lit up when the door was opened i could live with that (ain't gonna hurt the battery one bit).

does the $.99 bulb function that way?
My 2 for 99-cent eBay LEDs work just like the stock dome light bulb, but much brighter and whiter (without being bluish).

It functions just like the stock setup. The light comes on when the door is opened, and a bit after closing the door it dims then goes out. The dimming is not quite like the incandescent bulb which is linear all the way down to off... this dims to perhaps 20% before going out.

The 'glow' when off is barely perceptible... only visible at night and very very very dim. Sort of like a glow-in-the-dark sticker after it has lost most of its glow.

Try 'em, I think you'll like 'em, what have you got to loose but 99-cents! I liked them so much that I ordered more!

~toaster
 

·
Registered
Joined
·
333 Posts
As part of my LED headlamp project I found the solution to LED licence plate lights that blow after just a couple months and LED dome lights that glow when turned off.

For license plate lights: Get a CREE LED festoon bulb with a CANBUS chip. They're easily identifiable as having heat sink fins on the back of the enclosure.

...

For dome lights: Get a festoon LED bulb with a CANBUS chip. Most eBay sellers lie about their LEDs having CANBUS chips, so be careful here. If the CANBUS chip is nonexistent or doesn't have a high enough resistance, the dome light will stay on when turned off.

Most good CANBUS festoons look like that CREE festoon above, but with normal LEDs.

...

To be honest, I'd just recommend getting the dome light as a CREE festoon with a CANBUS. It'll make your dome light amazingly useful.

My golden rule of buying LEDs: If they're dirt cheap, chances are they aren't going to work or not going to last.

"CANBUS" LEDs are the biggest misnomer. I wish the vendors would stop using the term. The LEDs have absolutely no CANBUS circuitry and have nothing to do with the vehicle's CANBUS.

So called "CANBUS" LEDs are nothing more than LEDs with a parallel load resistor to draw additional current, so as to not trigger the vehicle's burned-out-bulb warning. The load resistor generates heat which is why they typically have a heatsink on them.
Sorry to burst your bubble, but there is *NO* CANBUS 'chip' on these LEDs. :eek:

The festoon bulb in your 1st picture has a built-in switcher-type driver circuit so as to operate with consistent brightness over a range of voltages. This type will not dim to off like the stock dome light bulb. Because this LED's driver circuit requires some minimum voltage to operate, I'd expect it to go off if the smart's dome light drive falls below the minimum.

Your 2nd picture is just 3-LEDs, no visible driver, and likely a load resistor on the backside under the heatsink. The LED's load resistor may also load down the smart's dome light driver circuit to the point where it is below the LED's threshold voltage.

~toaster
 

·
Registered
Joined
·
861 Posts
Discussion Starter #13
so i am confused. what led bulb will be bright when on and go off or fade out when the door is closed (no dim glow that stays on)?
 

·
Registered
Joined
·
112 Posts
My Interior LED dome light is bright white just like I like it, but there is the faint glow when I shut the door, however I like the glow. My Mercedes SUV has stock bulbs and the roof lights, similar to the smarts dome lights glow as well, but it does turn off after removing the key.

I think I'll keep it.


The glow drove me crazy so I switched back to oem bulb after a week.


Sent from my iPhone using Tapatalk
 

·
Registered
Joined
·
729 Posts
but it does turn off after removing the key.

The part I didn't feel comfortable with was the fact it would not stop the glow. The morning after I installed it I went out to garage and it was still glowing 12+ hours after the last time the car was run. I was worried it may cause a drain on the battery.
 
1 - 16 of 16 Posts
Top