We have had a 5-foot fluorescent in the kitchen for many years. For the past few years it has been running a thin 35 watt echotube and adapter. The ends have been hot for years and the plastic tube holders are falling apart.
This light is often left on for long periods and I have been meaning to convert it to LED for some time. I could have used a LED tube replacement but that leaves the old wire-wound ballast in circuit. So this evening I got enthusiastic and converted it to LED strip lights.
I had a reel of cool-white 5035 LED strip that draws about 14 watts per meter at 12V. The modification had to fit into the existing, operate on 230-240V AC and be electrically safe. I also had a 240V 20 watt 22-36V 600mA LED driver.
DANGER – MAINS VOLTAGES INVOLVED – DON’T TRY THIS AT HOME
Applying 12V DC to the LED strip, I measured out a length that drew about 700mA. Then attached 3 strips in parallel to the original fitting cover. Three strips in series should operate from a 36V supply, and the LED driver would limit to a maximum of 600mA. This should keep the LED current below the maximum rating and deliver 20 watts or close to it.
I stripped all of the original fitting wiring, ballast and starter, but left the fuse terminal block in place. Drilled a few holes and mounted the driver. The LED panel is connected to the driver low voltage side using a 2-pin JST plug and socket; making the cover easily removable. The LED driver provides a isolated output, so it’s safe to touch the LEDs while on.
About an hour of cleaning and assembly and it works. The light output seems to be about the same as the original fluorescent tube and power draw will be no more than 22 watts, of which about 2 watts is dissipated by the LED driver, inside the fitting. It’s not the tidiest looking fitting but the light output is good and doesn’t produce noticeable shadows. At 22 watts, it should save 10-12 watts.