Tony, John, et al,
Speaking for myself (as only I can do), and as one who has blown a
standard ammeter up (oops), I can say that it's quite a simple job
to beef up your ammeter. The important bit of the ammeter is only a
single loop of wire which produces a magnetic field varying with
the current flowing through it, which in turn deflects the needle.
All one needs to do to increase the capacity of the gauge is to
remove the old loop and fabricate a loop with a (slightly) larger
diameter out of larger gauge copper wire. You will of course need
to silver solder on some new terminals so you can screw the loop
onto to input posts, but that's the hardest part of the job. You
need silver solder because the wire will probably get pretty
damn hot in operation and ordinary solder may get hot enough to
melt, making the car come to an abrupt halt.
Frank Biedermann
1969 TR6 PI
Adelaide, AUSTRALIA
> In your analysis, I think you might be mixing the functions of automotive
> ammeters and voltmeters. In almost all automotive applications, the
> ammeter MUST reside in the charging circuit/line as you suggest if you are
> to get a true picture of charge/discharge (and you are correct in that the
> starting current by-passes the circuit - but it is the only cct to do so
in
> most vehicles). Therefore, the headlights, and other loads are IN the
cct.
> I am not sufficiently familiar with modern alternator charging patterns,
> and battery charge rates to know if your thesis of load leveling is true
or
> not. I do know that my Chrylser Concorde will happily get my AVO to FSD
on
> the 50A range quite easily (but whether that would occur on a TR, I just
> don't know).
>
> However, I would suggest that you DO need to match the alternator output
to
> the ammeter range, if you want to avoid blowing the std. 30A unit by
> installing a higher output alternator. You may have noticed that later
> LBC's equipped with ammeters had the +-60A Lucas units for just that
> reason. The cheaper, and maybe less satisfactory solution used by some
> budget conscious folks in the autoindustry (B-L?) led to the use of
> voltmeters rather ammeters - the following might help explain why.
>
<- Snip ->
|