COB Light Issue

This generation of COB lights are trivial to connect. Just connect the 110V ac or 220Vac to the unit - all of the power regulation is built into the COB light. The AC voltage is rectified but never smoothed with capacitors. Capacitors are what typically fail as the best ones are rated for 105C and for those of us fixing motherboards, TVs, monitors and other electronics well know - the failure is nearly always caused by the capacitors. Because there is no smoothing the lights will flicker at 120Hz. Basically the 110V units have strings of LEDs which turn on at 80V. So when the recified line voltage exceeds 80V they turn on and the COB power regulator limits the current.

The issue is that LEDs are 4x more efficient (~10%) than incandescent lights (~2.2%) and so the 70W COB light draws 95W and 85W of that is heat that has to be removed.

To remove the heat I tried a flat aluminum plate and then ~2010 AMD heatsinks - the aluminum blocks and then the 125W rated ones with a copper plate and four heat pipes. Both only seem to work for perhaps 15W without the cooling fan - so the COB LED will exceed 100C after ~5 minutes and start to reduce it's power output. Having the fan turn at a very low speed is good enough to keep the 20W and 30W COB lights working at full power. Either heatsink, with a 20W or 30W COB light held down with two secrews, only lasted 5 minutes before it exceeded 100C and started to reduce it's power output.

ItemPower draw
LED COB light AC110V-45160-F10613 120V, 70W94W below 100C, 55W at 105C
LED COB grow-light AC110V-6040-F2525 120V, 30W41.3W below 100C
LED COB grow-light AC110V-6040-F2525 120V, 20W28.4W below 100C

This first picture shows the 70W COB light and two 20W COB grow lights.

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Toyota Echo Emissions Failure

Our Toyota Echo was generating P441 P442 P446 error codes - very infrequently and then daily. Replacing the gas cap didn't help and then poking under the hood I noticed that one of the hoses involved with the evap. emissions system was cracked:
checked hose
hose not flexed
hose flexed

I replaced the hose and then put the original gas cap back on and the trouble codes returned. Installing the new gas cap solved the problem. As always - it wasn't a simple problem as both the hose and gas cap had to be replaced.

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