> Dan, sorry but I must differ with you. My TR4 ammeter does not have any
> LARGE cable running to it and it does not register when the ignition is
> turned off. This is the original configuration. Maybe a check of the wiring
> diagrams in Haynes or Bentley will show why. I'll check tonight.
Without knowing the car in question, the ammeter could function
perfectly well without having all the current flowing through
the dashboard.
Remember, an ammeter is simply a voltmeter in a special
application. Current flowing across a resistance creates
a voltage drop across the device.
An ammeter involves two devices, one is a fairly well known
resistance, the other is the voltmeter. Flow the current you
want to measure accross the resistance (known as the shunt) and
knowing the voltage, compute the current.
By keeping the resistance very small (much less than one ohm)
the resistance doesn't affect the circuit being measured to
any real degree.
You COULD run an ammeter that had all the current going to
the dash. However, this is based on the notion that the ammeter
has to be a unit, shunt and meter, together. It doesn't.
The shunt could be placed anywhere, or an existing high current
line like a battery cable could be used as the shunt. Then simply
place a sensitive voltmeter in parallel with the cable, calibrate
it with some simple math, and put the meter in the dashboard. Only
the tiny wires to the meter need to enter the cabin.
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/ Trevor Boicey 1992 Celica GT 1975 MG Midget /
/ tboicey@brit.ca One parking spot left! /
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