Lan & Jim,
The isolator that Jim spoke of may already be provided by the factory. I
think most of the later model tow vehicles, at least those with factory tow
packages, isolate the charge line when the ignition switch is turned off.
My faithful old '94 Ford only provides power to the trailer charge line when
the ignition switch is in the on position. I've never looked for it but I
assume the ignition switch routes low amperage current to the relay which
actually controls charge line current.
Harvey
----- Original Message -----
From: Jim Dunmyer <[EMAIL PROTECTED]>
To: Multiple recipients of VACList <[EMAIL PROTECTED]>
Sent: Monday, March 05, 2001 6:44 PM
Subject: [VAC] Re: Why Car & Trailer Battery to Univolt?
> Lan,
> Connect the new converter to just the trailer battery. Actually, there
> is usually a "Power" wire coming from the tow vehicle to charge the
> trailer battery while on the road. To use it, you need an isolator,
> either diode-style or a relay to prevent running down the vehicle's
> battery by using too many lights in the trailer while the tow vehicle is
> plugged in. That "Power" wire (and associated ground wire) is too light
> to do much charging, I've measured it at only 4 or 5 amps.
>
> <<Jim>>
>
> [EMAIL PROTECTED] wrote:
> >
> > This is probably in that large category of dumb questions, but I'm
replacing
> > the 40 amp Univolt on my '70 Overlander with a Newpark 40 amp. Aside
from
> > having fewer fuses and circuits, if that's the right word, the new box
also
> > has connections for only one battery, the one from the trailer. The
original
> > Univolt has two, one for the trailer battery and one for the auto
battery.
> >
> > My question: What is the purpose of having a connection from the car
> > battery? I guess if the auto battery is run down, you could charge it,
but
> > since electricity runs both ways wouldn't it pull power from the trailer
> > battery when you crank the engine? So, in connecting to the new voltage
> > converter should I try to jury rig a connection to both batteries, or
just to
> > the trailer battery?
> >
> > --Lan Sluder
> >
> >-
> --
>
> <<http://www.oldengine.org/members/jdunmyer>>
> <<[EMAIL PROTECTED]>>
> <<lower SE Michigan, USA>>
> <<mailto:[EMAIL PROTECTED]>>
>
>
>
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