Date:         Sat, 30 Oct 2004 20:23:40 -0700
Reply-To:     mark drillock <drillock@EARTHLINK.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         mark drillock <drillock@EARTHLINK.NET>
Subject:      Tail light lense temps , part 2
In-Reply-To:  <41844FCF.7010709@earthlink.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Ok, I put a 50 watt bulb in to replace the stock 21 watt brake light on
the passenger side. I also put in a new 21 watt bulb on the driver's
side brake light. I pushed the brake pedal down and braced it in
position so the brake lights stayed on. Then I watched the temps, back
and forth, every 15 seconds, looking for the hottest temp spot on each
side. I aborted the test after 4 minutes as the temps were still
climbing and I did not want to hurt anything. I have no idea how high of
a temp the lens can sustain without damage. I suspect that it could take
quite a bit.

50 watt brake light lens after 4 minutes, 190 degrees
21 watt brake light lens after 4 minutes, 135 degrees
non-lit area of tail lenses, 65 degrees

Putting a 50 watt bulb in for the tail light also makes no sense to me
since it is important for following drivers to be able to tell the
difference when I step on the brakes. Doing so might cause a melting
problem given enough time on a hot summer night. Otherwise perhaps not.

I ordered two 35 watt bulbs and my plan is to use them for the brake
lights. Here are the rear lighting upgrades as I plan to do them.

stock 5 watt tails will become 10 watt
stock 21 watt brakes will become 35 watt
stock 21 turn signals will become 50 watt

I will report any problems as I become aware of them. I have spare tail
light assemblies so should any damage occur it will not be a major concern.

Mark



mark drillock wrote:

> .......................
> I installed one 50 watt bulb in the passenger side turn signal and a
> stock brand new 21 watt bulb in the driver's side turn signal. I turned
> on the 4 way flashers and waited to see what happened. The 50 watt bulb
> was noticeably brighter, naturally. I own a digital infrared temp gun so
> I used that to monitor the temps of the lenses in the area lit by the
> turn signal bulbs.
>
> After 10 minutes I started checking the lenses to see what the temps
> were. The 50 watt side was hotter, of course. It kept climbing for a
> while and after 15 minutes of flashing these are the temps I saw.
>
> 50 watt side, 165 degrees F.
> 21 watt side, 115 degrees F.
>
> The areas not lit by the bulbs read about 70 degrees and the air temp
> was in the 50s.
>
> I may try the experiment again with the brake lights and then I will
> prop the brake pedal such that the brake lights stay on constantly.
>
> Mark
>