Alternator for cub

[Mht]

Mine is wired with the single wire from the alternator to the right side of the amp meter looking at the face of the meter which corresponds with the charge side of the meter. The left or discharge side of the meter has a wire going to the battery and a wire going to the switch. The second terminal on the switch has one wire going to the coil and a second wire going to the light switch. If I check the battery voltage when not running it is 12 plus volts. If I check voltage right after starting when the alternator is charging at its highest rate it’s 14 plus volts. It sounds like you have your alternator wired to the discharge side of your amp meter. What is the battery voltage with the tractor not running. The running voltage should be several volts higher

[Ohiowoodchuck]

12.5-12.7 is what it reads with engine off. Like mentioned earlier 12.9 is the highest I’ve seen while running. My gauge only has two terminals.

[Mht]

My gauge only has two terminals also. Alternator wire to the charge side. Wire to the starter and wire to the switch on the discharge side. With only 12.9 while running id have to say your alternator is not working properly

[Ohiowoodchuck]

Do you have a heavier gauge wire going to the battery. I have #8 going from alternator to ammeter gauge. #10 from starting post to other side of ammeter. I have the headlight switch wire and the ignition wire on the same side as the alternator wire. I have a regular battery cable coming from battery to starter post.

[Mht]

I think I used 10 gauge for all my wiring. The wire to my switch is on the same side as the wire to the battery. I ran my light switch wire from the ignition switch not the amp meter so the light can only be turned on when the ignition switch is on

[Ohiowoodchuck]

Ok thanks. I checked it a few minutes ago. I had a little over 13 volts at the amp gauge coming from the alternator. I’m happy with that as I would have to charge the battery several times during a season. I’m going to change out the wire from the starter post to the ammeter as it’s a crimped ring connector. I’ve been soldering all my terminals on. I think I’m loosing some voltage thru this wire.

[Gary Dotson]

All the discussion about ammeter wiring has little to do with the fact that your alternator is just not working. First, do you have battery voltage on the large alternator post? If yes, you're probably going to have to add the diode, to get it to excite.

[Ohiowoodchuck]

How’s it not working. It’s putting out 13.2 volts at wot. A good battery is 12.6 volts. I don’t think I’m going to see 14 volts out of it.

[Mht]

I agree that your alternator is not working properly. It should be giving you a reading of close to 15 volts

[Gary Dotson]

I missed your "little over 13v." post. Is 13+ at the alternator post or at the battery? If it's 13+ at the alternator post, it's not working properly but if it is significantly higher at the alternator post than at the battery, you have wiring gremlins to sort.

[Mht]

I just went to my shop and checked voltages on my cub. I’m checking a system with a battery and alternator that are less than a month old. Battery voltage while not running is 13 volts. As soon as I crank it the voltage jumps to 15 volts. If everything on your tractor is good I feel you should see voltage while running and charging at more than 13.2 volts. If after confirming that all your wiring and terminals are sound and all connections are clean and tight and your voltage is still only 13.2 I would remove the alternator and have it tested

[Jim Becker]

Although as already stated, your ammeter wiring has little to do with your charging problem, it sounds like you do have it wrong. It should be wired as Ohiowoodchuck described his. All electric loads should be fed from the same side of the ammeter that the alternater is connected.

[Mht]

Thanks for that response Jim. Now that I think about it a little more that makes sense. I’ll need to change my wiring. I’m always amazed at what I learn here on the forum

[Ohiowoodchuck]

After putting just the alternator on the right terminal and everything on the left at full throttle I’m getting 14.2 volts. I’ll have to find my amp clamp and see what I’m getting that way also. I think it will work just fine at 14 volts.

[Eugene]

Test to make sure you have the alternator wired correctly.

Engine and everything off. Check for amp draw at battery. Disconnect one battery cable, multimeter set on 20 amps. One multimeter lead connected to battery terminal and the other lead to the battery cable.

Amp draw should be in the milliamps and not amps.