Thursday, October 1, 2015

Generating Light without a Fire

Much to our surprise, we found that some of the fluorescent light fixtures in the cabins on LUX were overheating. One had been accidentally left on during part of the winter and we're fortunate that it didn't start a fire.

Evidence of Overheating

These lights are Labcraft and consume up to 1.2 Amps, depending on how many bulbs are installed. Replacing the offending bulb was the short-term fix, but we needed something that would never overheat, even if accidentally left on for months at a time. The light fixtures are nice, so we decided to install LEDs in them.

We found FlexFire LEDs, (ColorBright Natural White - Spec Sheet) which were reported to be very bright. They come in a roll and you cut off as many as you need, in 1-inch chunks. They aren't the cheapest around, but they seem to be much brighter than the other LEDs we've seen. 
The FlexFire LED Instruction Sheet
Unsoldering the Board
We started the modification by removing the label and unsoldering the board from the switch - the two points labeled with arrows in the picture. The board has several connections to the lights and a bunch of discrete components. We clipped the wires and unsoldered most of the components. The transformer and a couple of capacitors were left because they don't affect the operation of our modification.
Ballast Board With Components

Ballast Board Without Components
A hole was drilled between the electronics compartment and the light bulb area and wires routed to power the LEDs. A jumper was installed on the PC board to connect the +12v and ground connections to the switch.
Jumper the Power Leads to the Switch

Next, cut the LED strips to the length that fits where the lights used to be located. We cut 11 inch strips of LEDs. Only cut where it says to cut. There are two small solder pads that are obvious if you look carefully at the strip.
Sizing the LED Strips

Solder connecting wires to each LED strip and then connect them to the power leads that connect through to the PC board. Then remove the adhesive paper backing and stick them into the fixture. The connections to the power leads were soldered and covered with heat shrink tubing.
Soldering Wires to the LED Strips

They Are BRIGHT!
The new LED lights are BRIGHT! They seem much brighter than the old fluorescent bulbs and consume 0.4A per fixture. We converted four of the lights (one in each cabin) in a few hours.

After writing up this post, I discovered the Mike Boyd has an excellent pair of writeups on the subject:


1 comment:

Brent said...

Great project! Thanks for sharing.