OT - Charging circuit on small gas engines

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Definitely not a tourist attraction.

When I lived in Concord I felt that way too, but it's much closer to the high-tech jobs. The surrounding towns are still NH, town meetings, pickup trucks and wood smoke. The cities of northern Mass are part of neither state, they're in the Third World.

That's part of the 70% they don't stock. They have only a mini lathe and a few of the unpowered machines like benders.

jsw

Reply to
Jim Wilkins
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Oh? Wish they told me that early on in my EE courses; I could saved a LOT of homework...

Reply to
David Lesher

Yup. With the engine off, the battery reads something like 13.6V freshly charged, and once the engine's running the voltage across the battery terminals is 16+V

I phoned Onan today and have an inquiry in regarding what I should be seeing. The secretary said the tech who knows that information was gone for the day, but she'd get back to me tomorrow.

RWL

Reply to
GeoLane at PTD dot NET

Put 2 silicon diodes in series with the battery to drop 1.4 volts, giving you the ideal 14.6.

5 amp 25 volt should do.
Reply to
clare

Yes, that is a bit high. Do you have a wiring diagram for that engine? If so can you locate where the alternator is getting exciting voltage from and see whether there is a way to put a resister or regulator in the line to control the output.

Have a look at

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is not your specific problem but it does tell you how to control an alternator.

Reply to
john B.

Try a known-good battery.

jsw

Reply to
Jim Wilkins

I did that today. I had the original diode and a 10A diode. It didn't change it even 0.5 V

I think I'm going to buy a voltage regulator and be done with it. If I were better at electronics, I'd build one. I recall reading about the circuit and there's a specific (transistor?) that's a voltage regulator and the output is biased with a resistor to produce the desired voltage. A pretty simple circuit from what I remember reading, but it's a long time ago.

RWL

Reply to
GeoLane at PTD dot NET

The battery is brand new and I charged it before attaching it to the generator.

RWL

Reply to
GeoLane at PTD dot NET

Your test probes should be on the battery terminals themselves. Is that how you are taking your readings? Placing the test probes on the clips attached to the battery can sometimes provide false readings.

--Winston

Reply to
Winston

Give the freshly charged battery a day's rest for the surface charge to dissipate, then it should measure 12.6 to 12.8V. You could discharge it to

Reply to
Jim Wilkins

Putting the ammeter between the two battery terminals would fry the meter. I had one lead attached to the cable and the other to the battery terminal. That's how I could tell the battery was receiving a

1.5 A charge.

RWL

Reply to
GeoLane at PTD dot NET

Or open it's fuse. The context of my comment was a voltage measurement, though. The symptoms you outline are consistent with measuring the charging circuit without a solid connection from voltmeter to battery, or an 'open' cell in the battery.

That is proper use of an ammeter. If we are seeing only 1.5 A into the 12V battery while providing

16 V across it, I suspect the battery is dead. Open circuit. No Longer With Us. Pining for the Fjords.

--Winston

Reply to
Winston

I suspect it is a permanent magnet "alternator" with a "shunt" regulator (usually combined with the diode rectifier) so has no external sense.

Reply to
clare

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