The
objective was to make the light assembly weigh less and last much longer than the
incandescent lamp systems. This translated to fewer repair costs over a 10 to 20
year period and a lower energy bill. However, many of the cheaper lights are made in
China, where quality control is almost nonexistent. I would bet that the circuit
board on these defective LED lights contain only one solder side. Single sided boards are
not good for outdoor applications where temperature swings are extreme. The
temperatures can put too much stress on the solder joint, leading to cracks as shown
below. A double sided board is much stronger.
|
Traffic Light with Bad LEDs |
As illustrated below, in a double sided circuit board,
the solder forms an eyelet around the component lead. This prevents the lead from
pulling through and dramatically increases the solder to component lead contact area.
The result is a very strong solder joint which can tolerate temperature swings.
|
Double Sided Circuit Board
|
|
|
Crack in Component Solder Joint |
Crack in Component Solder Joint |
|