Key light conversion to LED

[BennyM]

Didn't somebody do a write up on converting the standard BMW key to an LED? The battery in my key doesn't seem to have the voltage required to power an LED. What is the normal voltage for the key battery? Thanks.

BennyM

[AZ_Jason_S]

I found this with a search.

http://www.bimmer.info/forum/showthread.php?p=10526&highlight=led+key

The oem batt is 1.5v I think too little for an LED.

[winfred]

i thought about doing it once but something like a photon or one of the many other cockroach sized lights run on 6 volts, they work ok on 4.5 and suck on 3, i got board and didn't look into to much after that

[BennyM]

Notice where Phil says that somebody did a write up on it. That's what I was looking for. Thanks for the voltage info. I need to get a different battery.


I found this with a search.

http://www.bimmer.info/forum/showthread.php?p=10526&highlight=led+key

The oem batt is 1.5v I think too little for an LED.

[AZ_Jason_S]

One thing I just noticed that write-up missed, you should use a resistor before the LED on the + side. Probably something between 1K and 5K ohms. I am not sure exactly, it depends on the LED specs and the batt volts. Otherwise if you put the LED straight across + and -, it should burn out pretty quickly.

I could ask our Elec Eng at work tomorrow. I just write sw, so I am dangerous with electrons. He is an LED expert, we use LEDs like mad.

[Bill R.]

here (http://bimmer.roadfly.org/e34/messages/archive/msgsy2001w09/74569.html)







Didn't somebody do a write up on converting the standard BMW key to an LED? The battery in my key doesn't seem to have the voltage required to power an LED. What is the normal voltage for the key battery? Thanks.

BennyM