Increase Cheap DOB Lifespan

 

It has been observed that cheap DOB Leds found in the market in large amounts dont last long. They may run a few hours to a month or so and then the SMD LEDs on them start to fuse. Based on my observation, the material used here is cheap and designed to fail. A 9 watt DOB emits around 3 watt worth of light and 6 watt likely is wasted as heat. I have observed 3 watt led bulbs to be brighter than these. These plates get very hot within a minute. Placing them on a heatsink may extend its life a bit but eventually it fails within a short period.

I thought I would try an experiment by dropping the current flow to these things by using a 105J PF Capacitor in series. In doing so, I observed that the DOB gets hot to a reasonable amount. I hooked the whole setup in a bulb and ran it for about 5 hours per day and its failed on the 2nd day. 2 SMD LEDs fused with a black spot in the center, meaning they burnt out. So, I believe that even though the current was reduced, the heat and current flow was still too much for the cheap SMD LEDs.

So, to reduce the current even further and also reduce the heat, I added another 105J PF Capacitor in series to it. Note - IN SERIES - NOT PARALLEL. After doing that I observed that the DOB runs a little warm without heatsink, which is a good thing. So in this case, even without a heat sink, the thing should survive. The brightness too, isn't much reduced. So I hoked it up in the bulb and ran it many hours. The bulb runs little warm and is reasonably bright. So, this way, the lifespan of the DOB should be increased. You can even use smaller PF Capacitors to reduce the current even further thus boosting the lifespan even more. You can even use this method for Alpha DOB LEDs to end up with bulbs that will presumably never ever fail.

In my openion, manufacturers of LED bulbs will tend to over drive them so as to last within the warranty timeframe. If all bulbs last forever, its bad for business right? :) The idea I shared here is known as underdriving and LEDs will love it since they are run at low power and comprimizing a little brightness. At the end of the day, its about observation and balancing out things for your LEDs.

Here is a circuit diagram to  help you understand better.