Greg :
First of all, either the standard of generators you get are higher than
I got, or you've been very lucky. I burnt up two freshly rebuilt 22700
generators (plus the one already in the car) in the space of a year,
just by turning the control box up to about 26 amps max.
Second, it depends to a great extent how you use your car, and in what
weather. Starting a cold (0C) engine takes a lot out of a battery,
especially if the ignition is the stock points setup (and no ballast
cutout). It takes roughly 50 amp hours to recharge a typical TR3-4
battery (yes, that's more than it's capacity, they are not perfectly
efficient), and my experience is that a fully charged battery can't
handle more than 3 or 4 cold weather starts before it's too flat to turn
the engine.
Short trips in cold weather require a lot of 'excess' charging capacity,
to put back in the battery what it took to start the car. If your
winter driving is constrained to short trips, the problem is even
worse. Using the numbers above, it takes roughly 15 amp hours to
recharge after a cold start. If your trips only average 1/2 hour each
(at charging rpm of course, idling at stop lights doesn't count), then
you need 30 amps of charging capacity, over and above what it takes to
run the heater, headlights, engine and wipers (which was measured at
20-21 amps on a bone stock TR3A). Thus, 50 amps is minimum charging
capacity to avoid a dead battery in this scenario.
BTW, I wouldn't say my TR3A alternator conversion is the prettiest
thing, or the best. In fact, I would change many things if I were doing
it again today. But I've logged probably 100,000 miles (on two
different cars) since I did my first one in 1974, and mount failure has
never been a problem for me. I do have a little trouble keeping the
bolt into the water pump housing tight <g>
Randall
59 TR3A daily driver
Greg Solow wrote:
>
> I truly don't understand all the interest in converting a +4 or a 4/4 to an
> alternator.
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