Cooked Battery

wagwar · January 09, 2013, 03:59:24 PM

The Odyssey PC680 start battery for my generator got cooked by the little magneto on the Kubota D950 engine! We were about half way home from the Arcadia rally and pulled into a Wal-Mart. When I went to start the genset, nothing. So, I was able to jump start the genset from my 12 volt center tap on my 24V house bank. It was a pita, but we got home.

Once I got home, I pulled the gen. start batt out and it was swollen almost to bursting. The battery shop declared it cooked or overcharged. So, I got a new one, connected it up and started the genset. When I tested voltage at the battery, it was almost 17 volts! I shut the genset down and that is where it stands.

Does anyone know how to adjust the little magneto to lower the voltage? I don't want to cook another $80 battery.

wg4t50 · January 09, 2013, 04:05:08 PM

Is it being charged from a belt driven alternator. OR from the generator wiring / control box ??
Dave M

Len Silva · January 10, 2013, 05:41:03 AM

The simplest and probably cheapest way would be to eliminate the engine charging and just use a small battery charger run off the generator.

junkman42 · January 10, 2013, 07:00:41 AM

Take the alternator off and have a shop repair it! A new one on ebay is less than 100 dollars! The proper approach. John L

Low Class · January 10, 2013, 08:01:24 AM

I am sorry I can't help you with your problem.
Where did you buy a PC680 for $80?
I need one for the motorsickle.
thanks

wagwar · January 10, 2013, 09:02:18 AM

It's a D 950 3 cyl. diesel. The battery is being charged (overcharged!) by a belt-driven magneto, not an alternator (I think they are different animals, but I could be wrong).

I had this genset apart this fall, but I don't recall seeing any regulator or adjustment. I'l go take another look.

junkman42 · January 10, 2013, 11:43:07 AM

The regulator is internal on Mine. There are some models that use a waste regulator which is pretty crude and just holds down voltage to a fixed value! How about a picture? Worth a thousand words! John L

gus · January 10, 2013, 02:41:39 PM

I don't think your magneto is charging the battery, never heard of one doing that?

It is probably a cheapo thing integrated into the flywheel. You could probably use a resistor to cut down the voltage to 13.5 or so, they seldom produce more than 0.5 to 1.0 amp.

My old Onan had one of these.

If you do use the bus batt to start the gen be sure to disconnect it after it starts or it will drive your bus VR crazy - been there!