Date:         Thu, 20 Sep 2007 17:06:50 -0400
Reply-To:     Wesley Pegden <wes@CS.UCHICAGO.EDU>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Wesley Pegden <wes@CS.UCHICAGO.EDU>
Subject:      Re: Back-up lights
In-Reply-To:  <20070920203129.4B8E01165C3@hamburg.alientech.net>
Content-Type: text/plain; charset=ISO-8859-1

Just wanted to point something out
I often people talk halogens in a way that suggests they put out more
heat than their standard equivalents.  Seems to me it must be the other
way around:  A 50w halogen and and 50w standard bulb both output the
same amount of energy in a second (50 Joules).  The halogen produces
more light, because it is (a little bit) more efficient.  It must output
less heat then....

Of course, a 50watt halogen will still output more heat than a 21 watt
standard bulb.

I think perhaps the confusion comes from the fact that the halogens
operate at a higher temperature.  They give off about the same amount of
heat though---actually should be a little less.

-Wes

Mike S wrote:
> At 02:12 PM 9/20/2007, Ron Johnson wrote...
>> In addition to terrifically under-powered headlights on a Vanagon, the
>> back-up lights are also below expectation.
>
> Stock BU lights are a P21W bulbs (so are the rear turn and stop bulbs),
> which is usually crossed to an 1073 or 1156 in the US. One can instead
> use 1295 bulbs for an increase from 32 to 50 candlepower. You could
> also go to a 795, which is a 50W halogen bulb which produces 108
> candlepower. I would be careful with the latter, it gets quite a bit
> hotter than the other bulbs, and could melt the light housing. Should
> be fine for the limited duty cycle of these bulbs, though.
>
> Rear tails are P5W, which crosses to a 67 or 89. A 93 bulb will give
> you an increase from 4 to 15 candlepower.
>
> Oddly enough, my owner's manual says that the rear stop/tail light is a
> dual filament bulb, and spec's a 1034. In actuality, they are separate
> bulbs, as described here.
>
> The front marker/turn bulb is a P21/5W, crossed to a 1034 in the US.
> Brighter is a P3496 (27/8W), brightest a H1157 (50/15W).
>
> The 795, P3496 and H1157 will probably not be found at the local FLAPS.
> You can get them from http://store.candlepower.com/
>