Voltage Regulator

[BobRip]

So I took some readings this morning and this is what I came up with:

Battery with tractor off - 12.1
Battery @ 1200 rpm - 12.1
Battery @ 2000 rpm - 12.8

Alternator @ 1200 rpm - 13.5
Alternator @ 2000 rpm - 14.2

So everything seems to be lower than what you're saying it should be. Is the alternator for this tractor just underpowered or is there more to it than that? Initial symptoms were loss of power when I have more than one set of lights on. They are all factory lights except for one extra set. The rotation of the chute for my snowblower is also run off of a small electric motor. I can barely run one set of lights while operating the tractor after dark.

The alternator looks alright, but the battery voltage is low. I think you have a bad connection between the battery and the alternator. With the engine running and 1200 RPM, measure the voltage between the alternator positive post and the battery positive post. Also measure between the alternator ground (the case) and the battery negtive post. These both should be very low (less than 0.1 volts). Find which one is too high and measure voltage drop on sub sections of the leads. Like the battery negative post to the engine block. You should be able to isolate it pretty easily. I hope this helps.

 

[Rich Waugh]

Matt,

The numbers I initially gave you were a bit on the high side, and your numbers indicate that your alternator is functioning about as well as can be expected of it. I do agree that you may have a bad/weak connection between the alternator and the battery. With the engine at full rpm the battery voltage should read the same as the alternator output as long as there are NO lights or other loads on, provided that the battery is okay. Your numbers indicate that the battery is probably okay. The real problem you have is that you're expecting more from the OEM alternator than it is capable of delivering. As you noticed, when the lights are on the voltage drops precipitously - that is because the alternator simply does not have the capacity to handle the load you're putting on it with the lighting.

The OEM alternator is just barely adequate to keep the battery charged, but it is not sufficient to keep up with even just the headlights on. It only puts out somewhere around 10-12 amps at full output, so a pair of 65 watt headlamps uses all it has and then some, by the time you figure in line losses and such. Add in the taillights, brake lights, dash lights, work lights, etc, and you're going to gradually drain your battery, even though your alternator is working its little heart out.

If you plan to use your lights much, or that electric chute motor(you'd be surprised at how much current even a small motor draws), or any additional lighting, you really need a much bigger alternator. Fortunately, it is easy and inexpensive to achieve that. I replaced my OEM alternator and regulator with a 65-amp Delco 12Si alternator. The Delco 10Si and 12Si alternators are internally-regulated units so you don't need a separate regulator, and they're available in either a 1-wire or 2-wire (also sometimes called 3-wire) configuration. I opted for the 2-wire configuration since those begin to charge at a somewhat lower rpm due to being externally excited. The 1-wire units are self-excited so they don't develop full output until they're turning at about full engine speed on a diesel tractor.

I got my Delco alternator on Ebay for about fifty bucks and also spent another ten bucks for a voltmeter to mount in the dash, since the new alternator has too much power to run it through the OEM 35-amp ammeter in the dash cluster. I simply ignored that, installed the alternator with the excitation wire coming from the key switch "on" terminal and the output going directly to the "+" terminal on the starter where the battery is connected. I cut the wire that fed the OEM voltage regulator and capped it off. Since the new alternator is not feeding through the ammeter, it now only reads the amount of discharge from the battery for lights or other loads, which is fine with me. I know my battery is being charged as it needs it, since the voltmeter tells me what the alternator is putting out at any time. (grin)

The Delco 12Si alternator matched right up to my TY395 engine in my Jinma 304, all I had to do was swap the pulley from the OEM alternator to the new one and modify the support arm to position the alternator in a slightly better position. While I was at it I replaced the OEM V-belt with a new link belt from Harbor Freight. Took me just about three quarters of an hour to do the whole mod and now I can run the headlights, two pairs of work lights and a fan all at once, and still have capacity left over. I can also run my 2000 watt inverter when I need 120 volts in the field.

 

[greg_g]

x2; dirty or corroded connection somewhere, as your alternator eventually puts out sufficient voltage. Check also for loose or worn alternator belt or pulley.

//greg//

 

[Diamondpilot]

Many of us have also taken a piece of good 10 ga or 8 ga wire and ran it from the large post on the alternator directly to the large lug on the starter. This will bypass a lot of the oem wiring and help with charging.

I would also really check the ground wire to frame connection. Grind off the paint and make sure the cable is corrosion free on both ends. Coat with a good anti corrosion grease on both the frame connection and the battery.

Chris

 

[RonMar]

The voltage at the alternator should be almost exactly the same as the voltage at the battery. Yours is not, you have a bad connection somewhere.

As mentioned, check ALL the ground connections, at the battery, at the negative terminal where it connects to the frame, ect... For the positive side, from your main output terminal on the alternator where you get the 13.5-14.2V, that wire probably runs back to the main input terminal on the key switch. From there it goes back thru the amp meter + terminal, then from the ampmeter - terminal back to the main fuse. From the other side of the main fuse it probably goes back to the starter positive terminal, and from there back to the battery + terminal via the large gauge positive starter cable. With the engine running You should be able to step back thru these points I have mentioned and check the voltage at each point(measured to the same ground reference point), looking for one or more that have a voltage drop. When you find them, shut down the engine, lift the battery negative terminal to remove electrical power from the system, then one by one disconnect, clean and inspect the connections where you found a voltage drop. The goal here is to get as near to the same voltage at the battery as you have at the alternator.

With the key turned on, power from that main key input terminal flows thru the key to the fuse panel to power lights and such. One of those fuses is most likley labeled charge or CHG or REG. That fuse powers the regulator and provides the sens signal that the regulator uses to control the output of the alternator. Since your alternator is putting out nearly the correct voltage(14.5 +/- 0.5), I would say the circuit is probably acceptable from the alternator back to the key switch. SO if it were me troubleshooting this issue, as a half-step point, I would compare the engine running voltage at the main fuse with that voltage seen at the alternator terminal. If it is low at the main fuse, the problem is most likley back thru the amp meter wiring(and possibly a main wire harness connector). IF it is good at the fuse, then the problem is most likley at the starter or battery connections...

As a reference, my Jinma 284 outputs what I consider a barely acceptable voltage. It's output at 1200 RPM is 13.9 VDC at the battery. This is with all the lights off. Under the same conditions, with all the lights(head, running and rear work light) switched on, the voltage actually increased slightly to 13.95 VDC at the battery. The REG fuse on mine is right alongside all the lighting load fuses, so the regulator sees a little less voltage at that point and boosts the alternator output to maintain the voltage at that point which results in a slightly higher voltage at the battery with lights on. If the voltage regulator is working properly, The voltage should stay fairly constant with load and RPM changes up to it's current limit. Mine runs all my lights and still maintains an adequate charge voltage...