Hybrid Car – More Fun with Less Gas

Automatic Throttle Speed Control for 12 VDC Genny?

register ::  Login Password  :: Lost Password?
Posted by Ulysses on April 20, 2006, 4:33 pm

Hi.  I've been using the 'ol 4 HP engine driving a 65 amp 12 volt alternator
contraption for charging two 220 Ah 6 volt batteries (in series).  So far
I'm still using the built-in voltage regulator in the alternator and it
seems to be working out just fine other than I have to hook up a different
charger once a month to equalize.  When I first start it up I have the
throttle set to full speed and the output is about 60 amps for a couple of
minutes then drops to about 45 amps and after a few more minutes settles on
30 amps (which is just right).  After about another 15 minutes or so it
makes it's way down to about 15 amps.  When it finally gets below 15 I can
turn the throttle all the way down to idle.  Meanwhile I am adjusting the
throttle speed 3 or 4 times each time I run it.  Is there a simple way to
automatically adjust the engine speed based upon the load?  I did the Google
thing but didn't come up with anything that didn't require building
electronic circuits.  Will some kind of vacuum or selenoid control work for


Posted by Ecnerwal on April 20, 2006, 6:37 pm

I'm thinking electronics is the way to do it, but that may simply
reflect the technology I know well .vs. the technology I don't know as
well. I guess there should be a variation in engine vacuum as the load
changes, but the specifics of linking that up seem a bit dim to my
experience, while the electronics are pretty obvious.

I think the ideal electronic setup would be a two-method regulator,
which would vary the field amps for fine/fast control of output voltage
(and/or current), and play with the throttle (slower/cruder) as the
field amps got lower/higher (adjusting throttle to get field amps to
return to a set-point value). Might as well include your charging
method(s), equalization option, and temperature compensation so it's a
complete package. This would start by running the current at 30 amps (if
that's perfect) until a voltage set-point was reached, switch to holding
an absorption voltage either for a time, or until current dropped below
a set-point, then drop back to a float voltage and/or shut itself down.

On the other hand, some sort of wind-up spring timer or clock motor
attached to the throttle could possibly do it, if it gradually wound
down from full to idle over the course of an hour, from your description
of the current process.

Cats, coffee, chocolate...vices to live by

Posted by Ulysses on April 20, 2006, 7:41 pm



To me this is rather complicated and I have a simple mind :-|  I can do the
electronics but now you have me thinking that if I simply control the
current and hold it steady a variable throttle might not even be necessary.
Perhaps all I need is an adjustable resistor/rheostat and I can set the
current rate to 30 amps and perhaps even a bit lower to make the thing
quieter by adjusting the engine speed down to where it keeps running without

I'll scratch my head on this one for a while.  Seems like it ought to work.

Posted by clare at snyder.on.ca on April 20, 2006, 8:15 pm

On Thu, 20 Apr 2006 18:37:31 GMT, Ecnerwal

How about running the field coil through a "voice coil" type activator
on the throttle. The higher the field current, the stronger the pull
of the coil - ballanced against the governor.
*** Posted via a free Usenet account from http://www.teranews.com  ***

Posted by Ecnerwal on April 20, 2006, 8:20 pm

 clare at snyder.on.ca wrote:

Sneaky electro-mechanical approach - I like it.

Cats, coffee, chocolate...vices to live by

This Thread
Bookmark this thread:
  • Subject
  • Author
  • Date
please rate this thread