Down with LEDs for the OBC

[Blitzkrieg Bob]

I was repairing a bunch of LED lamps for a Boy Scout camp and figure that I was tired of burnt out OBC bulbs, so I took apart some old bulbs and sockets and fit a reisiter and LED to it.

Had to fiddle with the installation to get the polarity right, but they work.

The only thing I'm not sure of is the dimming function...I think the voltage drop is too little for the LEDs.

[632 Regal]

as I understood the LED's either work or dont work mattering on voltage...interesting project tho!

[pyro]

no... they dim as less current flows through

[Anthony (M5 in Calgary)]

as I understood the LED's either work or dont work mattering on voltage...interesting project tho!

The heater control/slider knobs are lit with LEDs and they dim. The dash light dimmer uses a PWM controller to change the duty cycle of the LED, dimming it and the incandescent lamps on the circuit:

Datasheet for the PWM controller:
http://us.st.com/stonline/books/pdf/docs/1408.pdf

SMT components including the L9610C PWM controller:
http://img.photobucket.com/albums/v11/interalian/113-1355_IMG.jpg

Power MOS transistor inside heatsink. Note the dimmer's icon is lit with an LED:
http://img.photobucket.com/albums/v11/interalian/113-1357_IMG.jpg

[Blitzkrieg Bob]

Took the car out & wife too, for a night on the town, and checked out how the LEDs looked.

They do dim down, not instantly, but gradually.

They seem to work well for the LCD backlight, but the function buttons are not well lit. do to the narrow beam from the LED.

I guess I'll be using a bulb for the bottom and LEds for the sides.

[Javier]

Javier

[Rus]

One way to get a more diffused light pattern from LEDs is to roughen up the exterior. When I installed LEDs in my sunroof and A/M switches, I actually shaved the LEDs at specific angles. That seems to have worked quite well for directing the light in the proper places. Hope this helps.

[stx133]

whats the procedure for removing the obc to get to the globes, what globes do you need. i want to do it all at once, not pull it appart, find i cant get the globes and have to put it back together to pull it apart againg when i get the globes.

[stx133]

let me save evry 1 the hassle, RTFM. for removal. dosent say what spec the globes are....

[shogun]

BMW part nos of original bulbs:
64 11 1 382 790 Bulb "Rot"
64 11 1 388 253 Bulb "Weiss"

But I do not know the Watt.

How to disassemble
http://bmwe32.masscom.net/johan//IHKA_lights/IHKA_lights.html

That is now for the IHKA bulbs.

[Blitzkrieg Bob]

The LEDs seem to work just fine for the upper side backlighting, but the bottom is not quite right, even after sanding, still did not light up the all buttons enough.

These LEDs are 50,000 mcd, pretty bright suckers but the beam is way too narrow to back light the buttons.

So, I just popped the last working incandescent bulb in to light the buttons.

[Anthony (M5 in Calgary)]

The LEDs seem to work just fine for the upper side backlighting, but the bottom is not quite right, even after sanding, still did not light up the all buttons enough.

These LEDs are 50,000 mcd, pretty bright suckers but the beam is way too narrow to back light the buttons.

So, I just popped the last working incandescent bulb in to light the buttons.

I recall seeing a dismantled OBC. The keypad is lit using a light pipe from a centrally located lamp which fits into a hole in the light pipe. To adequately illuminate the keys, the light source needs to emanate from the sides of the lamp. Incandescent bulbs rule here compared to LEDs.

[Blitzkrieg Bob]

neither do white men..oh yeah asians too