battery charge connection on B&S engine

[JHZR2]

Hi,

We have an older (bought in 1986) ariens rear engine riding mower that we have used to mow about an acre of hills every year. Last fall it kicked the bucket. It had an 8 hp old style (flat head?) engine in it. We got the correct new OHV engine, and have been installing it, fixing the retrofits for the seat placement, etc (the engine casing overall is slightly larger and laid out a bit different).

We're almost done, but I have one thing hat Im not so sure about. The old engine had a single lead from whatever the generator was on it, which charged the battery (it was a pull and ignition start engine). The new engine has a "harness" that has two leads coming from it. I think the intent is for it toattach to headlights, and for the charge circuit to be connected into that.

Anyway, the engine was running, and I was trying to figure which of the two was to be connected to the battery charge wire.

The problem is, the one with voltage was at over 19V

Seems a little too high for a lawn and garden charge battery. Is it correct, do I need to install some sort of resistor, or elsewhat can I do?

One has to be for the battery, as the schematic that came from B&S for the wiring shows it as connecting to the battery charge. It just seems that 19V is too high. Any ideas?

Thanks,

JMH

 

[brianl703]

I suspect that the other wire is the voltage regulator sense wire. This senses the voltage at the battery so that the regulator can deliver the proper voltage to the battery.

Without it connected, it's probably running at full-blast which is why you're measuring 19V.

 

[The_Jeff]

I bet you have unrectified AC for the headlights on one wire and a DC charge current on the other. 19v with no load isn't that awful; I bet with the battery on there it'll drop to 13.5v or so.

 

[brianl703]

When that battery is fully-charged, it'll present almost no load.

I don't see why this wouldn't be wired up as a typical alternator configuration:

One wire is the output. The other wire is the voltage sense. The headlights and the output wire are both connected across the 12V battery, and so is the voltage sense wire.

Otherwise...the engine stops, so do the headlights. Seems kinda dumb to make it that way.