Charging a 6-volt battery

I have a 6-volt charger, but how do I tell if the system in the Cub is a negative-ground post or positive-ground post? I've read enough around here to know that the difference is an important one, and that doing things the wrong way can reverse the polarity in the battery.

The manual I have for this charger shows that NGP systems have the negative wire grounded on the tractor itself, while the PGP system connects in the usual way -- pos to pos, neg to neg.

The system in the Cub is original, as far as I am aware.

I can take pictures if need be.

If you can unbolt the whole front end without destroying it you can bolt a hitch to it and hook it to a 3 point tractor hitch. If you wire the lift wheels you can control the cutting depth by raising or lowering the 3 point hitch on the tractor. If you do this it is a good idea to slot the holes in your tounge, or make it for a ball hitch so it does not bind up and bend your hitch if raised extreemly high. This was done to numerous ones in our area, and most of the front ends were thrown in the scrap iron pile.

Perhaps the biggest mistake when starting out is trying to cut to deep. They will do a pretty good job for you if used correctly.

They are made for pulling and a real test of driver skills trying to back one up in soft fill.

The positive post is going to ground, while the negative post is going to the generator.

Do I still disconnect and charge + to + and - to -, as Dig suggests?

Yes. If you hook the minus cable from the charger to the plus terminal on the battery and the plus cable to the minus terminal, you're going to blow something up. If you're lucky it's just the fuse in the charger. If you're not lucky you could blow up the battery. I was taught to always disconnect a battery when you're charging it. It's a little extra safety precaution that might save your life some day. And besides it's a good time to clean the terminals and check and clean the cable ends.

As Dell(WA) says on the N-Board; 'Clean, Bright, and Tight'

I still don't understand, though, why the + and - are reversed on the tractor. In other words, once I connect this again, why does the ground wire go to the + terminal and hot wire to the -? Is this just a quirk of the old 6-volt systems?

There are and were also DC trolley systems of each polarity. Depending on the relative locations of underground pipes with respect to the power connections to the trolleys and tracks, one polarity was better than the other at protecting those pipes from electrolysis. Sometimes that same argument was applied to automobile battery polarity.

And there have been tractors with one of each polarity, the JD diesels with electric start from the 50s though about 1969. They had a 24 volt system with the mid point grounded. Starting and charging didn't use ground, just 12 lighting loads but there had to be two 12 systems, one positive and one negative to keep those loads balanced so the 24 volt charging would charge the batteries equally.

Very many 6 volt tractors had the positive grounded. My gas 4020 though 12 volts had the positive grounded. With a generator it wasn't critical, so long as one polarized the generator when it hadn't been run in a long time and connected the ignition coil for the same polarity as the battery. It wouldn't run quite as good with reversed coil polarity.

With solid state, as in the rectifiers for alternators, solid state ignition and radios, polarity is a bit more critical. The wrong polarity destroys the solid state parts faster than the fastest fuse can blow. In the early days the radios were made with switches to set their polarity, even vacuum tube radios needed that. And while MOST alternators are made for negative ground, its possible to make them for positive ground or no ground at all and they are made those ways, but aren't common.

Gerald J., electrical engineer from Iowa

There's NO NEED to disconnect the cables from the battery.

Simply match the polarity of the charger's leads to the polarity markings next to each battery post.