Upgrade Electrical System - Briggs Twin

Status
Not open for further replies.
Joined
Dec 18, 2007
Messages
579
Location
Madison, Wisconsin
I've got a Briggs 422707-1529-01 in a John Deere 116. I'm getting high voltages at the battery and PTO Clutch (15.6v) and I think the issue lies in my stator. It's a dual circuit and not within specs when I check it against the Briggs Opposed Service manual. The DC amps are low compared to what they have published, and so are the AC volts.

I think my battery is good, still need to have it load tested to make sure, but the smart charger likes it which is usually a good sign. I'm getting 12.6v across the terminals, 15.6 when the tractor is running.

Assuming it is my stator, I have two choices. Stick with the Dual Circuit one, or upgrade to the Tri-circuit. I'm toying with the tri-circuit just because I think it will give me better capacity for charging and running the PTO. Everything I've read about the dual circuit stator is that it's barely up to the task. The tri-circuit would require a voltage regulator, but that's probably not a bad upgrade either. Net net - I'm looking at $58 difference between the approaches.

Would you do it?

For reference, I inherited this tractor and it will never leave my place. I have fond memories of driving it around my grandpa's place, and have far more money in it than it's worth. I'm OK with that, and OK with spending the extra if the tri-circuit is the more capable system for the future.
 
Good question. This all came about because I replaced my PTO clutch this summer. The 30+ year old clutch's bearings were rough, and since I depend on this tractor for snow blowing I thought I'd put a new PTO on it.

The new PTO - which was an Extreme PTO - started whining pretty much immediately. I tried to warranty it, they had me go through a bunch of troubleshooting steps but ended up telling me that the 15+ volts cooked the PTO coil and they refused to warranty it. I disagree that it would have happened that quickly, but that's another story. There's a line from Tommy Boy about a warranty on a box which pretty much sums up my experience.

I have a new Warner/OEM PTO coming, but would prefer not to install it until I have the voltage under control (assuming it's an issue)
 
Last edited:
I think this is the system where two wires bring AC power out of the stator and go to the two outside terminals on a rectifier regulator module. This module is usually mounted on the fan shroud to provide air cooling to its heatsink. The center wire on the module goes to the battery.

The rectifier regulator controls the voltage. It needs to be well grounded.

Not sure why you say what you have is "barely up to the task" when there is actually too much voltage.
 
The current system has two wires which terminate in a connector. One has a diode, and is the DC charging circuit. The other is AC for lights. There is no voltage regulator.

Everything I've read about the dual circuit system is that it will do the job, but there isn't excess capacity. Headlights dim with RPM, etc. I'm also seeing comments that most tractors with the electric PTO use the tri-circuit vs. the dual circuit because of difference in amps between the two. The dual circuit puts out 2-4 amps, an electric PTO needs 3-4 based on what I read.

I understand that volts are high, but aren't amps a better measure of capacity? My electrical knowledge is so-so, so I could be wrong. Everything I know I just read on forums, so I realize I need to take it with a grain of salt.
 
Last edited:
That is indeed unusual to find the unregulated system with an electric PTO. Usually those are on a very basic tractor where the battery is only used for starting. The lights are powered by the other circuit, and the ignition is self-powered. So the only thing the DC coil does is slowly charge the battery. If your ratio of starting to running is not typical, it can overcharge, leading to short battery life and/or the need to add water.

Do you really have 15 volts with the PTO engaged? I would not expect it to work that way. The dual circuit is really only intended to recharge the battery after starting, not to constantly power any electrical devices.
 
Last edited:
The cost of the parts doesn'tseem to be a killer ifit doesn't workout and if it does work all will be good.
 
Originally Posted By: mk378
Do you really have 15 volts with the PTO engaged? I would not expect it to work that way. The dual circuit is really only intended to recharge the battery after starting, not to constantly power any electrical devices.


I've not measured voltage with PTO running. The diagnostic procedure the PTO clutch company had me do is measure the voltage at the PTO connection with the switch on and engine running. That voltage was the same as what I'd measured across the battery terminals, and also at the stator terminal. I could measure it again tonight with the PTO engaged if you think that's a better measure.

Give the company's prognosis that the voltage killed their clutch, I figured I needed to get to the bottom of it before I put a different one on. Plus the concern that I might be cooking the battery too. Which is why I started investigating.

I do see a lot of comments online that 14ish is the max volts a PTO clutch is happy with. I'm searching for any technical guidance Warner has. No luck yet, other than the installation instructions saying it should draw 4 amps. It's a Warner 5215-35, Deere AM 122969

If this is all ado about nothing, I'd be happy. But I'd prefer not to damage a battery and clutch if I do have voltage issues.
 
Last edited:
I should also mention, this is a bit of a Franken-Tractor. I did repower it with a new engine, which came with the dual circuit stator. I just spliced it into the existing wiring harness and it worked, so I didn't dig deeper. That was 12-13 years ago now.

Looking at the Deere parts site, the original engine appears to have come with the tri-circuit stator. My tractor has a diode in the wiring harness, but no regulator. The earlier serial numbers in the series had something called a "diode module", which as far as I can tell rectified the current and also split out an AC circuit for the headlights. The break in production between that module and just a diode in the wire happened 1,000 tractors before mine.

I just wanted to point that out in case someone was familiar with these tractors and was questioning why I had a dual circuit stator, when the Deere site said something else.
 
Many OMC outboards used to run excess voltage w/o regulation. They advised to use the running lights at all times to keep the battery happy.

My guess is this is the same. With the PTO engaged it will "balance" the circuit and the voltage will be "normal" ...
 
You will probably find the voltage is well under 14 with the PTO connected and engaged and may slowly drop as the battery runs down with extended use. This isn't a big deal if you don't engage in extended use, and you charge the battery in the garage.

It would be nice to have the regulated system though especially if you're going to add anything else electric. LED light bar comes to mind. Those require DC, you can't use the AC lighting coil.
 
Last edited:
Wow! Spot on guys! I fired it up after work. 15.3v unengaged, and it dropped to 12.4 when the PTO was engaged.

The downside of that it that it's now outside the lower bound of the recommended voltage for the current PTO I'm trying to warranty - which is 13.2v to 14.0v. I'm still going to try for warranty though and see what they say. All I see Warner saying is that 12-14 volts is their range, so I think my new clutch will be OK.

Good to know that this isn't an urgent issue then. I would like to find a headlight module for the hood someday - but they are scarce as hen's teeth - so I was considering a LED light bar. Lights would certainly help with snow blowing.

What I may do is check it after the next time I snowblow and see how low the voltage has gotten by the end. If it's pushing 12, or below, I may end up changing out the stator sooner. Otherwise, it seems like a good summer project.
 
Last edited:
Status
Not open for further replies.
Back
Top