Commando 800 charging issue's

[hm12460 53]

Gentlemen, I recently acquired this little beast and have done a lot of work on it. I put a new battery in from our friends at Tractor Supply, the old one was done. With the engine off/key off, it is showing 12.75 volts across the terminals. With the engine running, I measured the voltage with my multi-meter with the scale on 0-20 volts dc. Couldn't get a reading. Moved the scale to the 0-200 volts dc and the voltage was flucuating from 125-190 volts dc!!!!! How can this be??? I've never heard of such a thing!! The old key switch was worn out, so I installed a new one. Bought a good used regulator/rectifier from Joe's Outdoor Power off of a C-81. It had the same part number. Didn't make a difference. Thinking my multi-meter was lying to me, I tried it on my John Deere, it shows 14.5 volts with the engine running, so my multi-meter appears to be working properly. My question is, wouldn't this extreme high voltage explode the battery? I did use the tractor to haul some firewood and it performed just fine. Iwould imagine the stator would be next thing to look at, but 125-190 volts dc?? I don't get it. The regulator/rectifier appears to have a good ground, the 3 spade terminals are clean. Idea's?

[KATO 115]

    Is this a new problem ...or maybe thats why the old battery was fried. Wrong wires from stator maybe

[Save Old Iron 1,566]

The only devices in an ignition coil based tractor capable of generating those voltages are

1/ defect in the spark plug wire

2/ arcing in the ignition coil

3/ arcing in the stator assy

whenever current flow thru a coil is stopped, the coil (stator, ignition coil) wants to keep the current flow going. The magnetic field in the coil will collapse and convert the magnetism into a high voltage and tries to keep the current flowing thru an open circuit.(bad wire connection or broken spark plug cable).

this electrical characteristic of a coil allows the collapsing magnetic energy stored in coil to be converted back to voltage - a really high voltage in excess of 200 -300 volts. This same action routinely takes place at the ignition points when the points open. The coil tries to spark across the points (high voltage jumping a gap) but the condensor absorbs some of the voltage and prevents most of the excessive arcing at the points.

So, we either have a spark jumping inside the ignition coil feeding back thru the 12 volt line back to the battery

or

a bad connection in the stator which is sparking and feeding a high voltage spike back thru the regulator. The regulator is not fast enough to prevent the spike from getting thru the electronics of the RR unit and the spike appears at the battery terminals.

I would go simple first.

Remove the electrical connector from the regulator and restart the tractor. Removing connector from the RR unit will prevent any spikes from getting to the battery thru the stator or RR unit. If the high voltage disappears, the problem is in the stator or stator wiring.

If the problem remains,

Check if the condensor is good (probably is if the engine is running strong)

Make sure the condensor is hooked to the negative side of the coil and the positive side of the coil is hooked to the ignition switch

Replace the spark plug wire

Replace the ignition coil.

Use the multimeter to re-check for the high voltage after each of the steps above.

Edited March 14, 2014 by Save Old Iron

[Save Old Iron 1,566]

one other option is your multimeter may not be properly shielded against the radio frequency interference spewed out by a sparking connection in the tractor.

 

the 200 volts is not actually entering the battery but is just being "picked up" by an inexpensive, poorly shielded multimeter. Even some expensive meters have issues with operation in a high RF environment and produce false readings.

[hm12460 53]

Chuck, thanks so much for your help! Had some time today to do some trouble shooting. I  discovered the coil was hooked up backwards. The + was connected to the points/.condensor, and the - was hooked to the key switch. After reversing the leads, with the engine running, the voltage started out at about 14.5 volts DC. Within 45-60 seconds, it was back up to 190 or so volts DC. I then disconnected the R/R and still measured 125-190 volts DC across the battery. At the earliest opportunity I plan to replace the coil and the plug wire. Is it possible, because the coil was hooked up backwards, that may have damaged it? (coil) Could it have fed back through the key switch, thru the R/R, and damaged the stator? Still reading about 190 volts AC across the stator leads. I do understand the RF issue with my multi-meter. The battery is right under the coil very close by. My multi-meter is a good 15-18 years old and was not an expensive one when new. The engine has been run enough now what with trouble shooting and all, I'm thinking I would have noticed some adverse effects with the battery or elsewhere in the electrical system. It starts and runs fine, even when the coil was hooked up backwards. No funny smells form the wiring either, battery has not burst and seems to be fine.

[Save Old Iron 1,566]

From what I have read, reversing the +/- wiring of an ignition coil only causes the secondary (spark) output to decrease somewhat. I have never experienced or heard of permanent damage caused to the coil due to this type of miswiring.

 

From your description of the 45 - 60 second delay before the battery voltage rises, it sounds like one possibility may be the wiring in the ignition coil may be breaking down and arcing the spark voltage into the primary coil. That is one possibility. The other possibilty is the condensor not filtering the voltage spikes from the primary of the coil. Condensor issues usually manifest themselves quite nicely as total failure to run or running VERY ROUGHLY  at idle and a failure to change from idle speed to partial throttle without severe stumbliing.

 

Just so we are clear - you removed the connector from the RR unit - disconnecting the output of the stator / RR from the battery - and the high voltage reading still remained?

 

If this is so, the only other components in the wiring able to produce / supress high voltage would be the igntion coil or the condensor.

 

It is also possible a break in the spark plug wire could be "broadcasting" interference into the voltmeter, much the same as you might hear in a radio under fluorescent lights.

 

Measure the resistance of the spark plug wire while flexing it, the resistance should be very low and NOT CHANGE while you flex it. Any jump in resistance would indicate a break in the internal wiring connections.

 

We could also try to measure the primary and secondary resistances of the coil AFTER it acts up. The issue with resistance measurements is the voltmeter only applies less than 1 or 2 volts across the windings of the igniton coil whereas the coil in operation applies thousands of volts across a broken section of the insultaion inside the coil. The test meter may not pick this one up on the resistance scale. I'll post a procedure to test the coil later this morning.

Edited March 19, 2014 by Save Old Iron

[Save Old Iron 1,566]

I just found an old(er) post regarding some waveform captures done on an oscilloscope connected to the primary of an ignition coil.

 

 

The green traces indicate the AC voltage present on the stator.

 

The yellow traces indicate the voltages present on the 12 volt line connected to the ignition coil. I'll outline this better for you on another post, but for now, look at the spikes normally seen on the 12 volt power line at the coil. Those large spike that fly off the top and bottom of the scope screen represent voltages near  200 - 300 volts !! It is the job of the condensor to delay those spikes somehat until the points contacts are phyically separated enough not to allow a spark to jump across their gap.

 

Most voltmeters just do not have the ability to accurately measure or even sense those spikes.

[hm12460 53]

Chuck, I thank you again for your support. The madness continue's! This is what I've done so far. Yesterday afternoon I disconnected the R/R from the stator and still have around 190 volts DC across the battery with the engine running. I measured the AC voltage coming off the stator at 28-60 volts, flucuating. I then reconnected the R/R. Today  I installed a new oem Kohler coil and plug wire. Still reading around 190 volts DC. Through this process I cleaned uo the spade connector's that connect to the R/R. Also cleaned up the terminals on the R/R. The ground is nice and shiny, bare metal. The engine has been run about an hour or so through all this and no ill effects seem to have occured to the battery. I'm starting to think hard about the RF interference you spoke of. It is my thought 190 volts going to the battery would have damaged it by now. Also, the points and condensor are new. The engine starts and runs very well throughout it's rpm range. As far as RF interference goes, the battery is located right under the coil and my multi-meter is going on 20 years old and was not an expensive one when new, so I'm guessing the shielding is poor.

Edited March 19, 2014 by hm12460

[hm12460 53]

On a further note I've come to the conclusion that it would be an excellent idea to bring along a multi-meter  to check the charging system when looking at old tractor's.

[Save Old Iron 1,566]

An additional thought - have you checked the spark plug wire for breaks?

Maybe a quick substitution of a resistor wire plug cable instead of the solid core wire on there now?

It is a long shot, but do you have any type of aftermarket de-sulfator hooked into the battery circuit?

[hm12460 53]

No on the desulfator. The plug wire is new and it is an oem Kohler specifically for Kohler small engine's. Would it be worth trying an automotive grade plug wire? Wouldn't running it for an hour or so at this high volage ruin the battery?

Edited March 19, 2014 by hm12460

[Save Old Iron 1,566]

If the battery is indeed charging above 16 volts then yes, this would be a dangerous condition in which the battery could crack and leak fluid.

 

We are running out of options and may need the 2nd opinion of another voltmeter.

 

The 2nd voltmeter could be a simple automotive voltmeter gauge from a local auto parts store or an analog multimeter from any local source auto parts / radio shack / sears, etc.

[hm12460 53]

If the battery is indeed charging above 16 volts then yes, this would be a dangerous condition in which the battery could crack and leak fluid.

 

We are running out of options and may need the 2nd opinion of another voltmeter.

 

The 2nd voltmeter could be a simple automotive voltmeter gauge from a local auto parts store or an analog multimeter from any local source auto parts / radio shack / sears, etc.

 

Thanks again Chuck, and I agree. I think my multi-meter has out lived it's usefulness. I must confess though, this experience was a good learning experience. Also, would an analog multi meter be susceptible to RF interference?

Edited March 21, 2014 by hm12460

[Save Old Iron 1,566]

Well sir, I have to admit I have had access to brand name, high quality meters throughout the years and do not recall ever questioning a meter reading due to electrical interferences. If "weird readings" were seen, I would have access to an oscilloscope to check for external interferences and circuit oscillations. The interferences were then immediately obvious. That is why I love the challenge of long distance blindfolded  troubleshooting sessions.

 

My thoughts are to obtain an automotive volt meter and replace (either temporarily or permanently) the ammeter gauge currently on the tractor. You will be able to constantly monitor the battery charge for any possible overcharge condition until you are satisfied the problem has been resolved. I believe this would be your best low cost option without adding additional tools to your tool chest.

 

To answer your question regarding the analog meter being less susceptible to interferences, the answer is it depends. Analog meters are less prone to interference from radio frequencies (like sparks / arcs from circuits) but are more prone to interference from strong magnetic fields that can exert a "pull" on the pointer of the analog meter.

Edited March 22, 2014 by Save Old Iron

[Save Old Iron 1,566]

another quick check for shoots and giggles ...

 

Jumper the + ignition coil terminal directly to the battery + terminal. This will bypass any issues, arcing, etc inside the ignition switch.

 

Restart the tractor and monitor the voltage present across the battery terminals.

 

If you have the ability to post a video of the meter jumping from 14 to over 100 volts, I would love to see the progression of the voltage change. We are certainly in one off territory with this one.

[hm12460 53]

I'll try to do that in a few days, gonna need some technical help posting a video on this site.

[Save Old Iron 1,566]

FYI

 

and this is with an internationally recognized top quality industrial multimeter.

 

The effects of external interferences can be very specific to models within a brand name and dependent on the proximity and type of electrical radiation.

 

 

Makes you think about holding the cellphone to your head all day long.

[hm12460 53]

Bought a new multi-meter and hurried straight home. Got the ol' honk running and sure enough!! 17-18 volts DC with the engine running. I am going to replace the R/R to bring the voltage down to hopefully 13.5-14.4 volts DC or so. Lesson learned, my old multi-meter is going into the trash. It has had a long and useful life. Chuck, thank you so much for your help and support!

[Save Old Iron 1,566]

Good deal.

What brand / model multimeter was at fault?

Before you swap the RR, run a wire directly from the RR case to the battery negative terminal. Corrosion under the current RR and between old body panels will cause a good RR to overcharge.

[hm12460 53]

I've got what I believe is a very good ground, shiny metal all around the attaching points, new fasteners and all. Will run a ground wire anyway, just to check. My old multi-meter is in the dumpster out by the road, waiting for the trash service bright and early in the AM. Forget the brand name, but I bought it from Northern Hydraulics back in the mid 90's.

[Pullstart 62,734]

Bringing an older post back from the dead.  Rylee’s Screamin’ Jimmy has a new battery, but slowly dies.  Checking the voltage while running, I am finding from 12 to 18 volts, constantly changing.  Is a voltage regulator a dead giveaway with those symptoms?

[pfrederi 17,635]

While she is running ground the F terminal on the genny and see what voltage you get at the battery  18 is to high. You should get a steady 14-15.  18 is frankly not really believable from an S/G  you sure about you multimeter??  Some digital ones have problems with fluctuating voltages.   Sorry I just assumed your Commando has an S/G does it???   i have had Commando 8 on the brain lately not Commando 800.  If you have the newer regulator sound like a bad ground run a jumper from the regulator housing to the battery - and see what happens...

Edited September 28, 2018 by pfrederi

[Pullstart 62,734]

11 minutes ago, pfrederi said:

While she is running ground the F terminal on the genny and see what voltage you get at the battery  18 is to high. You should get a steady 14-15.  18 is frankly not really believable from an S/G  you sure about you multimeter??  Some digital ones have problems with fluctuating voltages.   Sorry I just assumed your Commando has an S/G does it???   i have had Commando 8 on the brain lately not Commando 800.  If you have the newer regulator sound like a bad ground run a jumper from the regulator housing to the battery - and see what happens...

 

It is a starter/stator style K-181, not a s/g.  

Edited September 28, 2018 by pullstart

[pfrederi 17,635]

10 minutes ago, pullstart said:

 

It is a starter/stator style K-181, not a s/g.  

Ground eh regulator housing if things settle down it is ok just need its ground cleaned up.  If not then new regulator time...

[Pullstart 62,734]

Cool, I’ll check that before replacement.  Some of my plow trucks have electric pumps, I’m a fan of good and plenty grounds!

 

thanks for helping @pfrederi