Date: Thu, 15 Jun 2000 19:24:01 -0400
Reply-To: The Bus Depot <ron@netcarrier.com>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: The Bus Depot <ron@netcarrier.com>
Subject: Re: 2nd batt. charging and relays. The whole truth
In-Reply-To: <7a.6a48cef.267a9797@aol.com>
Content-Type: text/plain; charset="iso-8859-1"
Well, thanks for the education! So this means that my Hella kit is not only
very similar to VW's own design, but is also preferable to "heavier duty"
alternatives in many respects. I guess this is one case where bigger isn't
neccessarily better.
- Ron Salmon
The Bus Depot, Inc.
http://www.busdepot.com
> First, I'm really suprised that among all of the list members,
> not one single Electrical Engineer steped foward to explain this relay
> delema. So in a nut shell: Guess what folks, if your aux
> batt. is deeply discharged, and you're running 2ga. wire and a
> 75amp relay, the batt. will most likely draw 75 amps(or whatever
> your alt. can put out) at initial surge. But if you're running, lets say,
> a Hella relay, rated at 15amps, with the wiring provided, and
> with the same deeply discharged aux. batt., you are most likely
> gonna draw about 12amps at initial surge, and much lower after
> a short period of time. It's all related to the Gauge of the
> Wire. Really. Your dead batt. will draw what the wire can provide.
> Still don't belive me? Okay, lets see what VW did from
> the factory: On older models equipted with dual batts, the relay
> was rated at 15amps( I'm holding the original one out of my ' 79
> Delux in my hand as we speak) and the wire from said relay to the
> aux batt is 12ga. Believe me folks, nothing can suck down a batt like
> the old style Dometic 12v/120v fridges found in the pre-Vanagon Type 2's,
> and even when these batts are totally discharged,
> starting your eng. does not cause a pyrotechnic display. If it
> did, VW would have been litigated out of existance by now. If that still
> doesn't convince you, well just flip through the pages of Brightons
Studies
> in Electron Flow to get a clearer picture. Your dead batt will only suck
up
> as much as much juice as a given wire will flow. The batt. is not an
active
> device, like an electric motor, but a passive one, and will not suck your
> cranking batt dry at start-up (Unless you are running Massive gauge wire
> to the aux. batt. That is exactly why VW went with smaller relays and
> wire gauge.) Think of the set-up as a "trickle charger".
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