using an alternator as input source for solar charge controller

[Pete]

Hi Dr Zogg there are some pretty cheap electronic engine governors on Ebay, plus linear actuators seem to be reasonably priced.
Depends on how much you want to pay, and also how much time and dabbling you want to take to make it work.
Using a small permag motor as a tacho generator and another one as a servo motor with a transistor switch is pretty rough and ready but also satisfying to get running. Guess it depends on the time and the money equation.

[Pete]

Here is a simple circuit that worked on my bench with a tacho gen and servo motor. There is a bit of work getting the spring tension that holds the throttle closed right and the resistors the right value for fine adjustment but fun anyway

[rossw]

Here is a simple circuit that worked on my bench with a tacho gen and servo motor. There is a bit of work getting the spring tension that holds the throttle closed right and the resistors the right value for fine adjustment but fun anyway

Hi Pete, I'm a little perplexed by your circuit.
As drawn, if the higher base current (caused by higher tacho output) turns the transistor more "on", won't that REDUCE the output of the slave motor (by shunting more current through the transistor)?

Are you sure the fan is across the emitter/collector junction, and not in series with it?

[Pete]

Hi Ross, the slave motor pulls the throttle open against a spring, so when the revs rise above the preferred speed the tacho output is supposed to go up thereby turning the transistor on more and throttling back the slave motor. That will reduce the revs to the preferred output.
It seemed to do what I am suggesting on my bench. I am open to more suggestions, or better circuits, as I said it is simple.

[Fionn]

Dr_Zogg,

Or you could try this pictured below unless you just want to experiment. It runs on gasoline or LPG. this one is 24v and monitors the battery bank and charges appropriately and auto-starts and stops. $699 plus I got 15% off for ordering from www.12vgridtiepowerinverters.com just pay all up front and email them (find in your paypal transaction) about the discount and they are forthecoming.
Regards,

SN

Update, your link just had Volt instead of V.
I was in touch with that seller previously but at that time they didn't have an LPG version.
Yours looks to be of a different appearance to the units they have on their website currently though?

[ghurd]

I designed one like Ross', but much smaller. And no auto start.
Think 1hp ECM or 2 and a little Honda?
LM3914/3915, using 4 outputs, that turn mosfets on and off.
Lowest LED output turns linear actuator fastest, speeding up the motor.
Next lowest turns up the speed a little slower. Series resistor.
Voltage gap when the battery is about right.
2nd highest turns the speed down slowly. Series resistor.
Highest voltage turns it down fast.
Simple, electricity.
Never actually built one because I don't have a use for it.
G-