854 not charging

[littleredrider 409]

So been messin' around with some of the tractors, getting them out of mothballs from the winter. But since last year, my 854 doesn't charge the battery. I've had the S/G rebuilt, and they tested it with the regulator. When I first put it on, it would charge for a bit, then stop. Talked to someone bout what was going on, and said something about the regulator should be clicking or something. I took the cover off, started it up, and don't see or hear any clicking. I pushed on the contact and still doesn't do anything. Get to be a real PITA to get the jumper cables out to start it.....

[Save Old Iron 1,571]

as a first quick check

tractor running at 3/4 throttle

run a jumper wire from the "F" FIELD terminal on the SG motor to a good chassis ground. This forces the generator to put out maximum voltage and should cause the ammeter to show a charge. Since you are bypassing the voltage regulation entirely, DO NOT LEAVE THE JUMPER IN PLACE FOR MORE THAN 30 SECONDS OR SO. Once you see the ammeter jump to the charge zone, remove the jumper.

Get back to us with the results of this test and we will come up with a 2nd step to take.

[littleredrider 409]

Pretty sure I did the right terminals, and got nothing. I think it's stamped with an F, but not a good stamp and has paint over it, so hard to read. Grounded it right to the negative side of the battery.

[Save Old Iron 1,571]

The SG unit is obviously working as a starter but maybe not as generator. As far as the painted terminals, the larger gauge wire goes to the "A" terminal, the smaller gauge to the "F" terminal. The wiring to the "F" terminal should be easy to trace right back the "F" terminal on the regulator.

If you have a multimeter,

conduct the same test with a voltmeter placed from the "A" terminal to ground. With the voltmeter in place, ground the "F" terminal temporarily. The voltage on the meter should go above 16 volts. If it does, the generator is functional and the regulator is not.

Again, remember to jumper the "F" terminal to ground for a short period of time - less than 30 seconds should be sufficient to run this test.

If the voltmeter test shows good voltage out from the SG unit, we can then proceed to troubleshooting the regulator or the wiring.

As far as the regulator chattering - yes - the mechanical relays in the regulator will open and close several times per second to respond to requests for additional voltage and excessive curent flow. Over the next few weeks, I'm putting together a tutorial on the operation of a regulator unit. It truly is an opera of electronics and mechanics and well worth the effort to understand the operation.

[littleredrider 409]

I'll see if I can get that in today, supposed to rain for the next 4-5 days. I remember someone saying about the chattering, this doesn't do that. When I first put it back on, while running you could see the amp gauge charge, then it would go to the negative side, then back to charge. When it would go to negative, if you would tap the regulator it would go back to charging. I really should get new wires, key switch and amp gauge. Over the years someone replaced it all with a solenoid and generic key switch. Since I have a 702 dash/hydro set up on, I might use a push button and two way key switch.

[Save Old Iron 1,571]

Disconnect the battery (+) wiring from the battery before you go any further. If you fail to disconnect the battery, working with the relays inside the regulator case can cause the tractor to start up unexpectadley, and if in gear, start in motion.

Inside the regulator case you will find either 2 or 3 relay assemblies (most likely 2).

One will have only heavy gauge enamled wire and the second will have both heavy and lighter gauge enameled wiring.

The heavy gauge only relay will be the cutout relay. With the engine off, the cutout relay contacts should be OPEN. When the tractor is started and the generator is providing more voltage than the cutout relay is calibrated to, the relay closes and connects the generator to the battery. This iw were the chattering starts. No chattering if the cutout relay fails to close.

The cutout relay will not close if the generator is not producing a voltage over its calibrated set point - this is usually around 9 - 11 volts DC.

The cutout relay may close but if the contacts are corroded or pitted, even if the contacts look physically closed, they still could be electrically open. Again, no chattering.

The chattering comes from the second (or third) relay as they open and close to attempt to regulate battery voltage and maximum current from the generator. On low current draw from the generator, only the voltage relay will chatter. If the current draw is high from the generator, the current relay will chatter. If you have a 2 relay reg, only the one relay with both the heavy gauge (current regulation) and the light gauge (voltage regulation) will chatter.

Check the contacts on the cutout relay. If you see large amounts of material transferred from one contact to another, the regulator most likely needs replacement. It is possible to get a a little more life from the reg by GENTLY removing the pitting from the relay contacts by using a points file or a small piece of 400 grit wet dry sandpaper. Forget about emery cloth / garnet / aluminum oxide type sandpaper and do not ever use a heavier grit. The contacts have a tungsten COATING which when removed, causes rapid deterioration of the contact material beneath it.

p.s.

the relay contacts on the voltage / current relays are NORMALLY CLOSED. They open to stop overvoltage or overcurrent.

So .... Cutout relay is OPEN with engine off. Voltage / Current relays are CLOSED with engine off.

[Save Old Iron 1,571]

Check the braided flex wire between the regulator metal body to the metal mounting legs of the regulator. Rubber isolation mounts electrically isolate the regulator body from its mounting feet. The braided flex wire electrically connects the reg body to the mounting feet.

[littleredrider 409]

I took some fine sand paper and polished the contacts, so far so good!!! I did this to the 1055 too. Since the 854 has an amp meter and the 1055 don't, thought I'd try it and see what happens. I had an amp gauge from a 141 that I parted, hooked it up and it charges. So, they both have aftermarket key switches, so both need to be replaced and rewired...

[Save Old Iron 1,571]

I'm guessing the CUTOUT relay was at fault ? (the only one with contacts open when engine is off)

[littleredrider 409]

I guess. Kinda annoys me cause I took the regulator down for them to test when they rebuilt the S/G and said all was fine. I may have been, cause could be the wiring/connections on the tractor. I'm gonna rewire the 854 like a 702 with the push button starter and two way keyed switch, since I have the 702 dash and hydro setup on it.

[Save Old Iron 1,571]

Consider an SG regulator to be like a set of tires - it will eventually wear out. The sparks at the relay contacts will eventually cause deteriration of the contacts and the relays will either not close properly or become stuck together.

Inexpensive reg units may not have a tungsten coating on the contacts and deteriorate quicker than a name brand, higher quality unit.

[littleredrider 409]

It seems to be working now and then. I started it up, was charging fine, drove it a short ways, then it stopped charging. I shut it down, let it sit for a little while, started it up and still wasn't charging. Could it be the regulator is getting hot? Guess I should rewire and get some new clean rust free parts....

[Save Old Iron 1,571]

I really dislike the idea of cleaning the relay contacts with anything but a points file. If the relay contacts were deteriorated so far as not making electrical contact, cleaning them with emery cloth can only be a very temporary fix. If you have 400 grit and 1000 grit wet /dry paper, you could try to clean the emery scratches off the contacts with 400 and then polish them lightly with 1000 - but - this would be a temporaty fix at best. Sounds like you may need to consider a new regulator assembly.

[littleredrider 409]

After re-reading one of your posts it looks like mine might have seen better days. I thought I saw new ones at Tractor Supply. Are they decent?? Where could I get a decent one if not?

[Save Old Iron 1,571]

I personally have not yet had to replace reg's on either tractor I have that uses them. My 800 special and the Cub 104 get only occasion use by my wife as cart pullers and garden cultivators - so far so good with those two.

I can imagine you get what you pay for as far as mechanical SG regulators. Maybe someone else has had either a good or bad experience to direct you toward (or away) from a particular seller or brand.

Good luck - sounds like you have this one nearly back in business.

[littleredrider 409]

It's frustrating to say the least. I thought I had it fixed, then it doesn't charge. I'll swap the reg from the other one and see what happens. I'm pretty sure that one works, I can see the contact opening/closing, just has a junk battery....