Date: Sat, 8 Aug 2009 12:56:49 -0700
Reply-To: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Turbovans <scottdaniel@TURBOVANS.COM>
Subject: Re: setting up multimeter to check current draw
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fwiw,
I almost never find it necessary to measure amperage.
I do find it very useful to measure 'current drop' across grounds points
though, or connectors perhaps.
You don't want to see over about 300 millivolts current drop across a ground
connection.
you measure things like this by energizing the circuit, put the meter on
millivolt or auto range,
put one lead on the ground wire right next to the ground point,
the other on the car body. If it was the ideal ground point, it would have
zero resistance, and show no voltage drop across that ground point, or
connector or whatever. If more than 300 millivolts of the total circuit
voltage is at the ground point, that's not right. Should be less than that.
For a key-off current drain - like wondering if there is current drain with
the van off, all lights off etc...
I just put a test light between battery post and the cable.
It shouldn't light, or barely light.
typically.......the clock will allow it to glow a bit, then go very dim.
It's almost hard to kill power to the clock I think, except by undoing the
battery.
for measuring amps .....
sometimes you wonder if the starter is drawing way too much current.
there's a simple inductive amp gauge you hold over a battery cable while you
crank the starter. They only cost a few dollars. Very worth having,
compact, light, simple. Got 20 + years out of mine. It's helped a time or
two.
for tracing down shorts...........I have sometimes used a amp gauge, like
the type that you'd mount in the instrument panel, and an automatic circuit
breaker ......
with that little rig............you can mess with a circuit that has an
intermittent short..........and when you find it , or get it to short, the
amp meter will peg .......
and if it's way too much current the automatic circuit breaker will open the
circuit.
- some of my electrical tricks on cars and vanagons.
Scott
www.turbovans.com
----- Original Message -----
From: "Kim Brennan" <kimbrennan@MAC.COM>
To: <vanagon@GERRY.VANAGON.COM>
Sent: Friday, August 07, 2009 4:17 PM
Subject: Re: setting up multimeter to check current draw
> current draw is measured in amps. Not all multimeters have an amp
> setting. To measure amps, you need to break the circuit upon which you
> will measure the amps. Then you "reconnect" the circuit by inserting
> the two probes of the ampmeter, one to one side of the circuit, and
> the other to the other side of the circuit.
>
>
> On Aug 7, 2009, at 7:00 PM, Courtney Hook wrote:
>
>> OK, I've been through the archives (which I suck at) to find this
>> info, but can't find it. How do I set my multimeter up to check for
>> a current draw. Do I use the volts setting and go across the fuse
>> connections with the fuse out, or pull one of the battery cables to
>> place the multimeter in between? Complete instructions for the
>> electrical-handicapped would be great.
>> Thanks,
>> Courtney
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