[TR] Randall's Headlight Conversion

Randall TR3driver at ca.rr.com
Mon Apr 13 14:24:48 MDT 2015

Ok, as usual my opinions differ somewhat, so let me present my point of view and you can make your own informed choice.

> Randall is correct, the primary difference in an otherwise 
> stock TR2-4a is that an alternator will probably put out more 
> power at idle than a dynamo.

I see off-idle charging output, plus the higher peak output as being more important than idle performance.  With a total load close
to 20 amps, and the stock generator rated either slightly less or slightly more than 20 amps (I'm still running the original C39,
rated at 19 amps), the stock setup leaves very little margin for recharging the battery when running with lights, heater and wipers
on.  This can be a serious problem if you make many short trips in bad weather; for example I used to commute about 4 miles each way
to work and the generator never had time to recharge what it took to start the engine each time.  Converting to an alternator solved
that problem, as it would put a good 40 amps continuously into the battery (60 amps output less 20 amps load) during the entire

The stock generator also doesn't reach it's maximum output until the engine is turning fairly fast; which can be a real problem in
stop-and-go traffic.  At least for me, most of the time in heavy traffic gets spent in the 1000-1800 rpm range where the generator
is producing something, but not enough to keep up with the load.  The alternator setup that I had (using a bored out generator
pulley on the alternator) wouldn't do much of anything at 500 rpm idle, but was already producing 20+ amps by 1200 rpm or so.

>  But this is not necessarily an 
> advantage. Since power draw can vary a lot, the alternator 
> load at idle will vary as well. This makes idle RPM more variable

For some reason, that's never been much of a problem for me.  I just turn the idle speed up until the engine stays running even with
maximum electrical load and let it go at that.  One of my American cars even specified to set the idle rpm with the headlights on,
for just that reason.  If necessary during a traffic jam, I can pull the choke out just enough to get a little fast idle action and
raise the idle even more.  But then, I've driven a lot with engines that wouldn't idle under 1000 or even 1200 rpm anyway, so maybe
I'm just used to the fast idle.  

> Here are the LEDs.  Http://goo.gl/LMdLHU

Might be worth pointing out that those conversions are rated to put out considerably less light than the ones I selected.  They also
have a much higher color temperature, meaning the light is more blue.  I personally really hate blue headlights, but obviously it's
your choice.

As far as the fans failing, that is a legitimate concern.  However, fans that last 30,000 hours are not at all uncommon so I see no
reason to assume that these won't meet their rated lifetime.  And to be honest, with my average usage, I don't expect to live long
enough to even find out if they won't make it to 30,000 hours.  At 2 hours a day, 7 days a week, that's over 40 years!  If they do
fail before I do, then maybe I'll buy the other kind next time <g>


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