All points well taken. And since the furthest my car has made it is about 20
miles distance supported on jack stands, :o), I cannot support the adequacy
of the charging system to hold a charge. However, at one point in my
restoration I heard that you can have the original generator rewired to put
out an uprated output. After talking to numerous TR3 owners in our club and
elsewhere, I was deterred from pursuing this avenue. All by the simple
statement that they have had their cars for years and never experienced any
problems driving at night, during the day or whatever. Now granted, we are
talking about stock TR's with minimal or no auxiliary equipment (ie; radios,
etc.) but experience is indicating or presenting some confusion for me. None
of the owners have ever had to charge their batteries other than by the cars
generator output. But by computing the science behind it, it clearly
indicates a shortfall on the charging system. I guess and hope in the near
future to find out.
Alex
----- Original Message -----
From: "Randall" <tr3driver@comcast.net>
Cc: "Triumph List" <triumphs@autox.team.net>
Sent: Friday, October 13, 2006 10:02 PM
Subject: RE: [TR] Winter Storage Oil Change
> > Just a note on the alternator conversion. I put in a pair of modern
> > headlights in my 3. They are extremely bright at idle and the dash light
> > stays off, indicating adequate charging. My generator is an NOS one and
puts
> > out the specified charge. My NOS regulator needed to be adjusted. Just
> > curious if your gen and reg are performing properly.
>
> I went through this many years ago ... the stock TR3A generator was rated
at 19
> amps (although most cars will have the later 21 amp unit). I measured the
total
> load, driving in the winter with the headlights, heater & wipers on; at 24
amps
> !
>
> With a properly adjusted regulator, this can be seen in the ammeter ... it
> should show a very slight discharge under these conditions. If it is set
"hot"
> enough to still charge with everything on, it will overcharge with
everything
> off (reducing the life of the battery); plus there is a very real chance
it is
> allowing the generator to output too much current, which will eventually
> overheat and damage the generator.
>
> But even if I mis-measured and the load is less than that, the
> generator/alternator still has to put back whatever drain it took to
start the
> car, before you get to your destination. In cold weather, this can be a
> considerable chore.
>
> Batteries are kind of odd devices, not very efficient and their efficiency
> depends a lot on the charge/discharge rate. But say for the sake of
argument
> that it takes 60 amp-hours to fully charge a healthy battery from empty.
> Further suppose it will start the car 10 times (again we're talking cold
weather
> here). So probably it takes something on the order of 6 amp hours to put
back a
> single start. If you only drive the car 15 minutes after starting it
(which was
> about my commute to work in those days), that means the generator must put
24
> amps into the battery (as well as powering whatever devices are turned
on).
> Obviously, a 21 amp generator just isn't going to cut it !
>
> Randall
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