Cub Cadet 1110 voltage relay disengaging
 

Hi,

I believe this is a 1986 model. It has a 11 H.P. Briggs engine with a diode rectifier. I am stumped on an electrical issue I am having with overcharging resulting in the voltage relay kicking out and back on again after a minute or two. Here is some background:

- I removed the stator and blew out all of the dust/debris
- Stator consistently generates 30V AC at WOT
- I just replaced the diode rectifier with a NOS Cub Cadet diode assembly, which didn't seem to help.
- I disconnected all switches that can be problematic for a ground: Seat, mower clutch, neutral, and mower deck switches.
- Voltage to battery starts out at 13.5V but after 5 minutes or so of running WOT (with no accessories operating) the voltage slowly climbs to 16V, which causes the relay to disengage. After it "rests" a bit the voltage returns and the cycle starts all over. I can delay this cycle by running the mower deck, which pulls voltage down to the battery but the relay randomly kicks out anyway and shuts off the electric clutch until the relay resets itself.
- I noticed that when the relay disengages the voltage to the battery drops back to around 13.5V to the battery and is at 13.5V to the auxiliary connection but only a few volts coming into the battery connection as labelled on the relay.
- I also noticed slightly less voltage coming out of the auxiliary side of the relay than what is going in on the battery side of the relay, but only a few tenths of a volt difference
- The most bizarre thing is that this seems to be weather/temperature related; it is really a problem in hot weather and can kick out every few minutes or so after it has done so the first time but never kicks out during cold weather (I can mow all day long in the fall/spring without this happening at all).

Any help would be very much appreciated!

Thank you!

First, welcome to OCC.......... :Welcome2:

Do you have a Meter (VOM or DVM) to check resistance and know how to do so ???

:bigthink:

Hi Roland - thanks for the welcome! This looks like an interesting group. I grew up with Cub Cadets and I have been running this ‘86 since ‘92. It still has plenty of life left if it were not for this one annoying issue- everything else is working fine.
I do have a meter and have tested negative battery terminal to ground and there is continuity. If there are other areas I should be testing for resistance please advise.

Thanks!

Test the continuity between Battery Negative (-) terminal and the Voltage Regulator case (or housing). What do you have ???

There is no voltage regulator on this model. It has the diode rectifier in-line with the wiring = and unregulated charging system. I found this info/advice online from someone experiencing the same issue I am having and am wondering if it makes sense?? RPM's too high??:

"Whether you are checking the dedicated AC terminal, or the DC lead (upstream from the diode)........the voltage valve ought to be the same, whether AC[/I] or DC.
Rectifying 28 VAC does not yield 14 VDC.
Rectifying 28 VAC yields 28 VDC, but in half sine pulses.
Rectifying 14 VAC yields 14 VAC in half sine pulses.

In a rectified, but unregulated system, observed battery/system voltage will climb to reach the exact (or near) voltage value of the charging source ONLY when the battery has ABSORBED its optimum charge. If the battery is still lacking some charge, the observed voltage of the battery/system will be LESS than the final voltage the charging system is capable of.
ONLY after the battery is completely saturated (charged up) to its optimum point will you be able to observe a voltage level that matches the design parameters of the charging system.
So, if you are observing a voltmeter connected to the battery/system of a Dual Circuit system, and the battery is not TOTALLY CHARGED already.......you will not see 14 VDC.
Remember, this is one of the minimalist DC charging systems 2-4 amps max, so if the battery is not yet fully saturated, the VOLTAGE observed will be less than the design maximum output voltage of the charging system.
As the battery nears saturation, the observed voltage value will raise.
If the battery reaches the maximum state of charge on an unregulated charging system, the battery/system voltage will continue to climb, until it matches the ACTUAL output voltage that the charging system is making at that time.
And any time you exceed the optimum voltage of a battery, you are not actually charging the battery any longer, you are simply carrying on electrolysis, and boiling the juice out of the battery.

If this engine in this thread is outputting more than 14 volts (AC or DC), I believe it will be due to excess RPM."

When this tractor rolled off the Assembly Line, it had a Voltage Regulator.

Now, maybe this tractor is/was modified for something else.

Yes, I saw that same parts diagram a couple of weeks ago when I started looking into this issue and was banging my head trying to find a voltage regulator that didn't exist. Then I came across this and located the diode in my wiring harness: https://www.ihccw.com/wire.html?product_id=12867
(note that this says it fits 1110 models). So, maybe Cub Cadet made two versions of the 1110? This also has only a single lead coming off the stator and the VR you are showing in that schematic accepts two wires coming off the stator. Confusing.

What are your thoughts about replacing the diode system with a 2-wire VR? Maybe that would run more consistent DC to the battery??:
https://www.amazon.com/Automatic-Vol.../dp/B07V3BFXW9

I believe this is the regulator you want....

https://www.briggsandstratton.com/co...ernator_id.pdf

https://hkresale.com/products/briggs...yABEgIPwfD_BwE

Well, let's cut to the chase. (A) Take a picture of the Model/Serial Tag of the tractor, and post it here. (B) Take a picture of the Model/Type/Serial tag of the B&S engine and post it here.

Between the two, we can get to the bottom of this confusion.

Didn't even have to go look at the machine since the previous owner had this all documented in Operator's Manual :)

Found the below in Briggs' Engine Alternator Replacement Guide: https://www.briggsandstratton.com/co...eplacement.pdf
This explains why there are different charging parts options for this engine model. I might try swapping the diode rectifier for a regulator rectifier to see if that makes any difference. I'm thinking that because the diode continues to throw voltage at the battery (and ramps up voltage as the battery hits the "full" point) to 16V DC and then trips my voltage relay that maybe a regulated system will keep that voltage constant and not trip the relay?? Thoughts? I must have the 5 amp system since my engine is putting out 28-30V AC. So I know which regulator-rectifier I will need. - thanks!

I may have figured this out. If you recall from my first message in this thread I commented that the issue of the voltage relay kicking out seems to be weather-related:
- Hot weather = relay kicks out frequently, up to every few minutes
- Cold weather = runs fine, relay never kicks out
So, I wondered if the problem is NOT related to the charging system but possibly the relay itself that is failing, affected by hot weather. Today was a good day to try an experiment since it was 92F. I strapped the relay to a cold pack (see photo below) and went off mowing. Mowed for about an hour and had no issues with the relay kicking out, which also shuts off the electric clutch and stops the mower until the relay resets, but then kicks out more frequently between cycles. Afterwards I performed the same test that was always a surefire way of making the relay kick out: Tractor in park, running at WOT. As stated earlier in this thread, a diode rectifier will slowly increase DC voltage when the battery approaches "fullness". At that point is when the relay would always kick out. This time it did not! I ran the engine and saw voltage increase slowly to 15.6V DC. It held there for 10 minutes or so with no issues until I finally shut down the engine. So, I think I am going to try a new relay and see what happens.

Update: My new voltage relay (or circuit breaker depending on what parts site you look at - see #3 below) arrived today. I tested the old one first and had the same issues when performing the procedures described earlier. I swapped out the old for the new and - success! Everything is now working as it should; it was the voltage relay all along and nothing else to do with the charging system.