Tuesday, 8 July 2014

10 Years On

DIY Trailer LED Lights

About 10 years ago I built a pair of LED trailer lamps for my Father In Law. This was back when LED lights were stupidly expensive - and as luck would have it I had access to some high brightness samples. 

Anyway, the lights served their time in the harsh conditions of the Riverland and the plastic lenses finally turned more opaque than useful. 

After replacing with a set of lamps off eBay for less than $40 I thought I'd share what they look like now. 

Not too useful lenses.

Mounted LED board. 

On these I experimented with leaving the solder mask off the board, and letting the HASL finish act as a mirror. 

I've since found out that white soldermask does a much better job. 

Notice Decent Screw Connections

Front and Rear Comparison

The white wire in the pic above I'd used to test if the lamps still worked.  They did! But there are some ECW bodges on the back of the board.

Cut Traces!

You'll notice in the top left there are some cut traces.  Not a design fault, but a board fault.  IIRC there was a short that needed to be hunted down.  These cuts / bodge are only on the one board.

Another Shot.

These LED lamps were a very simple design - each string of three leds gets it's own current limiting resistor.  I popped open the eBay trailer lights - same deal inside of them there.  I've read some forums that this is a crap way to go due to voltage variation in car / trailers but if the leds all have around 2V across each, then there's about 6V across the resistors - a volt or two more or less around 12V won't have a big effect on the LED brightness.

However, I've promised my mate some custom LED tail lights for his 73 Valiant.  I might try something special for those!

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