[Vwdiesel] Low voltage GP's.. Linear resistance...?

Mike & Coreen Smith ve9aa at nbnet.nb.ca
Sun Feb 13 18:52:41 EST 2005

hmmmmmmmmm, you think pretty clear for a man with a head cold.

The thought had crossed my mind as well Arnie.
In fact, as I was doing my GP LED cct tests a la "Mark the Miser" UK, I was
using a light
bulb for my load, using Ohms law, etc. etc. only to find out my calcs were
NOT spot on.
I just forget which way it was now, but seems to me resistance wasn't as
much, the lower
I made the supply voltage (I had a number of smallish 6, 8, 10 & 12v
batteries I was playing with.)

I don't have any spare GP's to test with, so I would only guess the
resistance @ 5.5V would
be lower than at 12v, given some current flow, thus heat.  How much lower I
have no idea.
How much less heat I have no idea.

It'll be interesting to see where this experiment takes us.  Surely someone,
somewhere, somehow, has
tried letting their glowplugs warm the engine up an hour before they left
work, on a separate battery (apart from the main vehicles 12v battery) to
ensure they'd get home @ the end of the day.

Mike in NB...........tempted to try this myself, but I don't have a really
good, big 6V battery to try.
Best I could scrounge would be some old, tired, used 8V 2.3AH Lead acid
batteries. (quite small) that I
would be able to put in paralllel.
You'd also need a relay to remove the GP's from the cars' main CCT as soon
as the key was inserted in the ignition........who wants 20V on their GP's
if you forget to unhook/disconnect your "preheaters".


Mike, Coreen & Corey Smith
699 Rte 616 Keswick Ridge
E6L 1T1
----- Original Message -----
From: "Arnie Grubbs" <vhuntertdi at yahoo.com>
To: <vwdiesel at vwfans.com>
Sent: Sunday, February 13, 2005 7:42 PM
Subject: [Vwdiesel] Low voltage GP's.. Lineiar resistance...?

> I know I can't spell, but anyway.. :)
> I was just sitting here thinking about GP's at lower voltage..
> How do they act?  I know there are several different kinds.. fast and
> Do they act something like a light bulb, with resistance determined
> by the temperature of the heating element?
>  Maybe I am all wet on this.. heck.. I have had a head cold since last
>  Monday, and my head feels like it is going to bust open above my eyes...
>  I just got back a couple of hours ago from a rainy drive down to
>  to see David, and pick up a radiator for my green bunny...  It was nice
>  chat with David, but wish weather and my head were better, I would have
> to stay and BS for a while.. :)
> Anyhow.. back on GPs-
> If they are non-liniar, then 5.5 volts would not give exactly 1/2 the
> and therefore 1/4 the heat, as one would expect of a pure resistance
heater element.
> It would be interesting to measure the current, to see what it is at
reduced V, and how it
> changes over the time that the element is heating, at normal and reduced
> This will be something for me to do when it warms up a little and my head
feels like it is going
> to stay attached...
> 73'  Arnie - KA0NCR   in rainy Nebraska...
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