Diagnosing my Cub Cadet with a Kohler

[John M]

After 10 years of loyal service, my Cub Cadet is giving me fits. Has a Kohler Command 23hp. Battery keeps dieing. Heres what I
have so far:
Checked charging circuit, getting 14.3 - 14.6 while running 3400rpms (Normal runnng RPMs). 12.9 - 13.1 at idle. Battyer shows
12.8/9 with engine off. If I disconnect positive cable, I get the same reading between the battery terminal and end of cable, so
no parasitic draw. I can run it about an hour, cut it off, engine will not turn over, battery is down to 11.2/3 volts.

I have charged the battery and have it in the mower now. Charged it Wednesday night, slow charge. Yesterday, battery was dead
again, so thats telling me either a bad battery, which was new this year, or I have a short. However, this same mower, with this
same battery, sat for more than 2 weeks (since June25th), and started right up Tuesday. I would tend to tink this is a battery
issue, but this same issue is why I repalced thwe battery earlier this year.

Now, my question, since it is vry hard for me to get to most of the safety switches, could someone look at this diagram, you may
have to scroll down, and tell me, if there is poer to the safety switches when the key switch is off, or just when the key
switch is on. Id greatly appreciate it before I start pulling panels and such to get to these switches. (Note: This is not my
exact mower, but the wiring is exactly the same.)
Click here

 

[Dennis(IA)]

Does it go dead if you remove the ground cable? If yes, bad battery.

 

[John M]

That I do not know. Completely slipped my mind to try it. Ill call my son right now and have him see if its still charged, and if it is, take the cable off. Thanks for the reminder!!

 

[Dennis(IA)]

. Remove the ground cable (engine off) and hook the voltmeter with one lead on the cable and noe lead on the battery terminal, if you have voltage then something is drawing current . If you have a very small amount of a voltage reading this could be normal.

 

[John M]

I did that, but with the positive cable. I thought I mentioned that. Voltage was the same voltage at the battery with the cable attached.

 

[IanC]

If you have an electric PTO clutch it may be drawing more than your alternator is putting out, and with the PTO switch off you wouldn't have any draw from it.

 

[John M]

Ive thought about that too, but that wouldnt explain why it dies from sitting though. (Which has happened) Any idea on how much draw those electric clutches have, and where is the best place to check for that? PTO switch, key switch??

 

[El Toro]

You may have a voltage draw on your battery. Disconnect the negative cable from the battery overnight then reconnect it the next day. If the engine will start I would install a master switch, this will isolate the battery from being grounded. Hal

 

[John M]

Quick update, mower has been sitting since 8pm my time Thurday. Battery was weak, but had just enough ump to turn the engine enough for it to start. Son brought the mower up to the shop to charge the battery again. (Remember it was charged the night before) Gauge on the charger went all the way over,(8 amps) then dropped to around the 3amp section ofthe gauge. (This is an old Sears battery charger my Dad had, still works though!)

 

[guido]

Hello John M,

I would use an amp meter to check for a parasitic drain. Is the voltage the same at the battery posts and the cables? Voltage reading is potential NOT capacity. A battery load test is in order! A bad cell or a bad cell connector? Sounds more like a battery issue to me. It is charging the proper charging voltage. Is it getting to the battery?

Guido.

 

[fixerupper]

One quick and easy diagnostic is to pull one of the battery cables and touch it to the battery post in a dark room. If you see a tiny little spark you have a parasite. It doesn't tell you the amount of draw but like I said it's quick and easy.

 

[guido]

Hello John M,

I forgot to add this. Remove one of the cables and check the battery voltage then. Then check it after an hour or two. You'll know then. Its either the battery or the mower,


Guido.

 

[John M]

I can assume that voltage to getting to the battery, since thats where I checked to see if it was charging.

 

[John M]

Again, I have done this except with the positive cable, I get the same reading as with the cable attached. Switch is not an option due to the lack of space.

 

[John M]

It was starting to get darlk on me last night, but I didnt see ny spark, not that I was looking, but I would have noticed.

 

[sotxbill]

could be as simple as the charging diode is leaking.. or the battery has a shorted cell and slowly drops...

or... one of the safety relays is drawing current due to being stuck on...

faulty key switch...

Faulty pto switch...


get a schematic off the internet and start checking...

 

[John M]

Thats exactly what Im asking about, the switches. I have even provided a link to the diagram. I just want to know if there is
power to those safety switches when the key switch is off. I can not physically ckeck the switches without taking the most of the
cover plates and such off to get to them, and am hoping someone here can confirm that there is no power TO the switches with the
key off.

 

[Steve@Advance]

Looking at the wiring diagram, there is one wire from the battery to the ignition switch. With the ignition switch off, there should be no other connection to the battery. That is assuming there is no problem with the switch itself. That is a possibility though, especially if it is stored outside or water has entered the switch causing corrosion across the terminals.

The best test for battery drain is with an ampmeter. Most multi meters have an amp setting, usually have to rearrange the leads, set it on a low amp setting and be careful not to over amp the meter. To test for draw, disconnect one battery cable, connect the leads in series from the battery terminal to the disconnected cable. The meter should show 0 amps. To test your connection, turn on the ignition switch (do not try to start), the meter should read the amp draw. Turn it back off, the reading should drop to 0.

You can do the same thing with a test light. Connect it in series with a disconnected battery cable, the light should not glow. This only works with simple, non electronic circuits though, which yours is, so it would be a viable test.

From reading the post, I suspect you may have more than one problem. The battery sounds suspect. Take the battery back where you bought it and have it load tested. That will tell if it is a good battery. It will need to be fully charged to test it.

Another possibility is the charging system is not making enough amps to overcome the amp draw of the PTO clutch. Looking at the diagram, the charging circuit feeds to the ignition switch with a red wire to terminal L of the ignition switch. With the engine running up to speed, and the PTO on, and any other accessory on, check the voltage from the L terminal to ground. Then check the voltage across the battery. They should be both the same within a few tenths of a volt, and should be up around 12.5 to 13 volts.

If the reading at terminal L is higher than the battery voltage, the ignition switch is bad or there is a bad connection in the plug.

If both readings are the same, but lower than 12v, the regulator or alternator winding is bad.

Try turning the PTO and accessories off, engine running at speed. If the voltage comes up to 12.5 or so, there is definitely a charging problem.

You said that after running about an hour the engine will not turn over. Is that a very slow turn, as in a low battery, or no response at all?

If there is no response at all, that sounds like a safety switch. If it is a slow turn, and the battery checks out as good, could be a starter problem. Check the side play in the upper bushing, could be the starter is dragging when hot, pulling too much current.

 

[John M]

THANK YOU!!!!!!!!!!!!! Everything is checking out right, except for the fact I havent checked voltage running with the PTO engaged. I just wanted to make sure there wasnt suppose to be power to any of the safety switched befor I pulled these panels off, and will check my starter switch as well. Its never been out in the rain since Ive owned it, except for earlier this year when I didnt get back to the barn fast enough, but that warrants checking anyways, even though its fairly well protected from water running into it.

To answer your question about starting, all it will do is make the solenoid click, sometime actually turn over a time or two.

Again, thank you!!

 

[BarnyardEngineering]

You need the meter set on AMPS when you take the positive cable off and check between it and the positive battery post with your meter.

Remember the 10A setting on your meter almost certainly has a 10 second limit.

 

[Tramway Guy]

On my Cub Cadet (about same age) if you had the stock lights and PTO on, the alternator couldn't keep up and battery would go down. Since I changed to LED bulbs in the headlights; no more problem.

 

[MARK ROBKE]

You said you get the same voltage reading between battery terminals as well between the disconnected end of a cable and a battery terminal.With everything off,that means there is a draw.As others below have stated,set your VOM to the 10A scale,and check between the terminal and cable end.On that mower it should be zero-no ECM to keep powered up.Does not matter which cable,+ or -,just follow polarity with your VOM leads.All voltage/amperage draw should be zero with key off,if I read your diagram correctly.And of course,leave a cable unhooked over nite to see if it starts.If you bought that battery this spring,maybe it was a leftover from last year,sat discharged all winter,and is weakened.I always buy the higher amp hour rated battery,and wait til later in the year,if possible,to buy fresh.Mark

 

[MARK ROBKE]

You said you get the same voltage reading between battery terminals as well between the disconnected end of a cable and a battery terminal.With everything off,that means there is a draw.As others below have stated,set your VOM to the 10A scale,and check between the terminal and cable end.On that mower it should be zero-no ECM to keep powered up.Does not matter which cable,+ or -,just follow polarity with your VOM leads.All voltage/amperage draw should be zero with key off,if I read your diagram correctly.And of course,leave a cable unhooked over nite to see if it starts.If you bought that battery this spring,maybe it was a leftover from last year,sat discharged all winter,and is weakened.I always buy the higher amp hour rated battery,and wait til later in the year,if possible,to buy fresh.I always start/let run,and/or slow charge the battery over winter too.Mark

 

[John M]

Yeah, just realized I didn't word that right. Anywho, I'm convinced it not a problem with the engine charging.