I have been using a 60 amp GM alterntor in my 1967 TR4A for almost a year.
No wiring melt down or any problem. I used Dan Masters instructions to
make my conversion. My ammeter does bury the needle upon first start up
but very quickly comes back to below 30 amps and eventually to about 1 or 2
amps under general running conditions. You can get Dan Masters'
instructions for this conversion from the VTR pages or contact Dan directly
on the list.
Russ Messersmith
1967 TR4A
1972 TR6
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> From: Tony Rhodes <ARhodes@compuserve.com>
> To: Randall Young <ryoung@navcomtech.com>; Triumph List
<triumphs@autox.team.net>
> Subject: RE: Adding alternator to a 4A
> Date: Thursday, August 12, 1999 5:35 PM
>
>
> Message text written by Randall Young
> >
> >If you really want to isolate high charging current from the rest of the
> >wiring, one way would be to use a high current diode from the alternator
> >output to the starter solenoid. It won't conduct until the voltage
across
>
> >it rises to about 0.7 volts, which isn't enough to harm the wiring, but
> >will bypass any excess.
> >
> >Or, I can probably brew up a circuit using the old regulator, an
external
> >relay, and a "battery isolator" to bypass the original charging circuit
> >when the current gets too high, but it hardly seems worth the effort.<
>
>
>
> Randall, my idea, poorly expressed, was to brew up the "batttery
isolator"
> you
> describe. I want to protect the original wiring from the full charging
> current, but
> retain the ammeter as is. Even a shund across the back is OK only if the
> brown
> and brown-white wires are big enough, which I thought they were not.
>
> I had not thought that the original wiring was sufficient for 60 or 90
> amps. That
> brown-green wire going to the regulator looks like 12 gauge at the best.
> Is it really sufficient
> to carry that amperage?
>
> A high current diode with a 0.7 voltage drop seems just the ticket! When
> the battery is low,
> it will pass current and bypass the main wiring harness and go directly
to
> the battery. When the
> battery is charged up fully, it will not draw that kind of current to
cause
> a significant voltage drop.
>
> One question though, what kind of current do I have to draw through the
> original wiring to create
> more than 0.7 volts drop? I'd have expected more than 30 amps..... So,
> maybe the simple diode
> is not sufficient to adequately protect the original wiring.
>
> Do you have any more thoughts about "brewing" up a circuit with an old
> regulator?
>
> -Tony
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