Thanks, all, for the replies. I will try to answer all the questions and comments.

First, the alternator is a three wire, not a one wire. Battery post to the original line, except on #8 wire, not 12 that was there. Terminal 1 of the reg is to the original regulator hot (regulator removed), with a dash light in series. Terminal 2 to the battery post of alternator. Greg, talking to an alternator expert, there is no difference in the voltage regulators as far as voltage capabilities are concerned.

The voltage drop is after the ammeter. There is no voltage drop at the battery, alternator, or starter. So, and please correct me if I am wrong, I have figured the drop is in the lines that power the rest of the tractor. I think your solution, Mike, is a good one, amd makes sense. May have to do that if all else fails.

So you all have brought up a question.....The power for all the accessories comes from one wire from the ammeter, to the fuse panel, then out from there. I am guessing I probably need to replace that wire with a larger one, right? That could be where the voltage drop is, right? Please give me a good lashing if I am wrong..........

BTW, Tom, the lights are 55w OEM. And the problem was probably there all along, but the fact that turning on the lights put the tractor into discharge with the old alternator probably masked it????

TJ.

TJ, the method to measure the voltage drop ACCROSS any component is just as stated, set your DVOM to a suitable scale (200 mv or 2, 0 volts) and place a probe on each end of the segment of wire, with the lights on, note the value of the voltage. The closer the number is to zero the better. You’ll find that the light gauge wires will have the most loss, largest voltage across that segment. Don’t over look voltage drops across switch contacts. A ¼ to ½ volt is ok, keep in mind that the losses are additive, ½ + ¼ + ½+ ¼ = 1, thus a long thin wire with many segments is a bad thing.

I’m not competing with anyone. It’s a matter of presenting all the solutions and picking the one that makes you happy.

OK, Mike, so I will check the voltage drop across the main wire, and see what I come up with.

I think the relay idea is a good one, and the more I think about it, the more I am convinced to do it. And I also have planned to do the same thing for the glow plugs. I do want to isolate the problem now, though, to make sure that it isn't some other thing that will ultimately haunt me.

TJ.

My mistake on the 1-wire assumption, sorry. I referred to my WAI catalog, and it only had an exploded diagram of the current 10SI Series. But here's the thing - the “SI” in the model number stands for Systems Integrated, meaning that the voltage regulator is inside of the alternator. My initial concern was that you may have inadvertently daisy-chained the OE voltage regulator.

Going by your wire numbers, there have apparently been some changes since I owned a Jinma - so I'm going to ignore my old wiring diagram. These diagrams for 3-wire 10SI generic connections may help;

AWG rule of thumb for DC (harness) amps says 10 gauge insulated copper should handle up to 55A, 8 gauge up to 73. If I'm not mistaken, the OE alternator wire is no more than 12ga (<41 amps), more likely 14ga (<32A). Consider also the jumper wire from the ammeter + post to the keyswitch. It too should be replaced with a larger gauge. That said, it probably wouldn't hurt to upgrade to a HD keyswitch too.

//greg//

Right Greg, the losses tend to gang-up. The losses will never be zero, but 2% is a very acceptable value.