My first vehicle after I graduated college was a 2002 BMW 540i. I had always liked BMW cars after I got to drive one in high school and was able to get one of my own a few months after graduation. This year, along with 2003 for the 5 series really started to incorporate the now popular BMW trademark details – LED tail lights, adjustable HID front bulbs, Halo headlights, and on the inside – red/orange ambient lighting. Kind of a cool feature, noticed as I was driving the car home that night (from Kansas City to north of Sioux Falls, SD). Made things easy to see but wasn’t to the point of distracting.
I picked up an Infiniti M35x a little while after the BMW and this car had the same thing, but in the orange/gold color that Nissan’s have for interior lights. Again, was a nice feature to have, and didn’t realize how much I missed having that little bit of light in the car after I traded the M in for the WK limited. Being that the car was a Limited, and finding out that the WK2’s have this ambient light, I thought I’d see about putting it my Jeep. And of course these little guys had to be green!
I started doing some research one morning about LED’s, resistors, Ohm’s law (scary reminder of college!) and by the time lunch came around, I was on my way to Radio Shack for supplies. That afternoon I made a spreadsheet that could calculate the required resistance based on the voltage drop of the LED and the input voltage. I made it with columns for each of the LED types that I picked up, and also made a second set of rows to calculate the required resistance based on a running car electrical system, 13.5V. Here’s a screen shot, but if anyone would like the spreadsheet, shoot me a PM with your e-mail address and I’ll send it over.
I found a 9V battery at home and used that as my test setup to get an idea of each of the LED’s outputs. One set had a very narrow light path, and 2nd set was just a little brighter than the 3rd set so I decided to use the second set for my overhead lights. Here’s a shot of my test setup – nothing pretty, but it made them light up.
I took the setup into a dark bathroom to test the light pattern, then took them out to the garage and turned off all the lights to test the light output inside the vehicle. They seemed to do well in the dark so I went though and wired them up. Based on my calculator, I needed to hit 375 ohms for the lights in series. Since I couldn’t come up with a realistic way of connecting resistors to hit that resistance, I bumped it up to 400 and called it good. Testing the setup at 400 ohms:
After it tested out, I soldered everything together and applied the heat shrink to all connections.
I picked up an Infiniti M35x a little while after the BMW and this car had the same thing, but in the orange/gold color that Nissan’s have for interior lights. Again, was a nice feature to have, and didn’t realize how much I missed having that little bit of light in the car after I traded the M in for the WK limited. Being that the car was a Limited, and finding out that the WK2’s have this ambient light, I thought I’d see about putting it my Jeep. And of course these little guys had to be green!
I started doing some research one morning about LED’s, resistors, Ohm’s law (scary reminder of college!) and by the time lunch came around, I was on my way to Radio Shack for supplies. That afternoon I made a spreadsheet that could calculate the required resistance based on the voltage drop of the LED and the input voltage. I made it with columns for each of the LED types that I picked up, and also made a second set of rows to calculate the required resistance based on a running car electrical system, 13.5V. Here’s a screen shot, but if anyone would like the spreadsheet, shoot me a PM with your e-mail address and I’ll send it over.
I found a 9V battery at home and used that as my test setup to get an idea of each of the LED’s outputs. One set had a very narrow light path, and 2nd set was just a little brighter than the 3rd set so I decided to use the second set for my overhead lights. Here’s a shot of my test setup – nothing pretty, but it made them light up.
I took the setup into a dark bathroom to test the light pattern, then took them out to the garage and turned off all the lights to test the light output inside the vehicle. They seemed to do well in the dark so I went though and wired them up. Based on my calculator, I needed to hit 375 ohms for the lights in series. Since I couldn’t come up with a realistic way of connecting resistors to hit that resistance, I bumped it up to 400 and called it good. Testing the setup at 400 ohms:
After it tested out, I soldered everything together and applied the heat shrink to all connections.