[TR] Randall's Headlight Conversion

David Porter frogeye at porterscustom.com
Mon Apr 13 14:51:52 MDT 2015

..so how did this thread go from a temp gauge to alt. vs generator 
discussion. Hijacked or my server?

On 4/13/2015 2:24 PM, Randall wrote:
> 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
> commute.
> 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>
> Randall
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Dave Porter Porter Custom Bicycles 2909 Arno St. NE Albuquerque, NM 
87107 505-352-1378 Go HERE: my world www.porterbikes.com/

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