Kubota L4610 electrical problem (need help please)

[JWR]

lots of guesses here but, 1 your mechanic is an idiot if he thinks you need to be over 2000 rpms to charge, alternators charge at idle, diesel changes nothing about this

lets be clear your alternator is not charging, its as simple as that. with the engine running check at the positive post at the alternator itself. if not 13+ you have issue with the alternator it self or wiring for the activation, does this tractor have a battery light? does it come on? does it go out?

changing parts just to change parts is a waste of money and parts

Yeah, verily. I agree . The first thing to change is your "mechanic." Certainly getting good clean connections and conduction at the cables and frame, etc. are good advice but you must have something else going on. Replacing the alternator twice as you described is absurd.

 

[Kubotajoe99]

Thanks to everyone for all of the helpful advice! It's now been 24 hours since taking the battery off the charger and leaving it on the bench. It now reads 12.78v. While it was out of the tractor I completely removed the negative battery cable and checked the resistance from the clamp to the connector. It seems fine and measured 0.1 ohm. My volt meter actually reads 0.1 ohm most of the time when I contact the leads together, so I feel like the negative battery cable is good. I sanded down the connecting area and the connector to shiny metal before reinstalling.
Next I would like to eliminate the possibility that a faulty glow plug circuit isn't turning off after starting the tractor, so I started looking for the glow plug that has the positive connection, but I don't know exactly what it looks like or where it is. I found what I believe are 4 glow plugs in a single row and one glow plug not in the same row as the other 4, and that confused me. On the 4 in single row there is a single metal strip connecting them together. The confusing thing is that I expected to see all the glow plugs in a single row with positive connected at one end and negative connected to the last glow plug in the row. Something like this:

+ terminal connected to GP1 -> GP2 -> GP3 -> GP4 -> GP5 - terminal connected

What I think I'm seeing is like this:

- terminal connected to GP2 -> GP3 -> GP4 -> GP5
+ terminal connected to GP1

The one not in the row with the others, that has what I think may be the + terminal, has a spade type connector, so easy to disconnect. This is located on the right side of the engine under the fuel cap area.

Can anyone confirm that this is the positive terminal for the glow plugs? If so, my plan is to reinstall the battery, turn on the key but not start it, check the voltage at the + terminal of GP1 to confirm voltage, then check voltage at + terminal on the alternator and note it, then start the tractor then check the voltage again at the + terminal of GP1 to confirm that its 0v, then check the voltage again at the + terminal of the alternator again. I assume it should be over 13 volts at fast idle.

Today I took one last bench voltage reading before re-installing the battery. Prior to installation it read 12.74v. After installing with the engine off, I took a voltage reading at the battery terminals and it was 12.63 and then took a voltage reading at the alternator positive terminal and it also was 12.63v. Then when I started the tractor and let it idle at about 1400 rpm for a couple of minutes I took both readings again. At the battery terminals it was 12.46v and at the alternator positive terminal it was 12.90v. This surprised me so I redid all of the measurements again and got similar readings: battery terminals 12.48v and alternator positive terminal 12.85v with engine running. So I'm losing about 0.4 to 0.5v between the battery and the alternator power terminal when the engine is running. Does that sound right? By the way it doesn't appear to change the readings significantly if I disconnect the glow plug power wire or have it on. So two questions: Should there be voltage at the power terminal on the alternator with the key off? and, Should there be any voltage drop between the alternator power terminal and the battery terminals when it is idling at 1400 rpm?

 

[LittleBill21]

how many wires are on this alternator, if you disconnect the battery, what is the voltage on the alternator?

@rScotty do you have a wiring diagram?

 

[ruffdog]

I'm not sure how the battery was tested, probably not a rigorous test. I also don't normally run at 2000 RPM. I've owed that tractor for 20 years and usually run between 1400 and 1500 RPM and never had a charging problem until 6 months ago. I'm thinking it might be the wrong alternator, a bad battery, or maybe glow plugs draining the battery?? When it won't start, it is totally dead. Jump starts from car easily.

Most of the time the tractor is run at idle (1400 rpm)or within 100 rpm of idle? That ain't right......

 

[sunandsand]

"when it is idling at 14000 rpm"

Amusing typo, gotta be a Pratt and Whitney PT-6 turboprop. 1,500+ hp would plow that field in a heartbeat!


There's a fairly easy way to check if there is a drain somewhere (such as the glow plugs not turning off - are they on a relay? It might be stuck on).

Start the engine, disconnect the + terminal on the battery, and put a test light between the battery terminal and the wire you disconnected. If it lights up, something, somewhere is drawing current. If it doesn't light, there is no load draining the battery (on a diesel, no electricity is needed beyond startup).

If there is no load/no light, next step is to load test the battery, and expect it to be bad - won't hold a charge.

Best Regards,

Mike/Florida

 

[Kubotajoe99]

Today I took one last bench voltage reading before re-installing the battery. Prior to installation it read 12.74v. After installing with the engine off, I took a voltage reading at the battery terminals and it was 12.63 and then took a voltage reading at the alternator positive terminal and it also was 12.63v. Then when I started the tractor and let it idle at about 1400 rpm for a couple of minutes I took both readings again. At the battery terminals it was 12.46v and at the alternator positive terminal it was 12.90v. This surprised me so I redid all of the measurements again and got similar readings: battery terminals 12.48v and alternator positive terminal 12.85v with engine running. So I'm losing about 0.4 to 0.5v between the battery and the alternator power terminal when the engine is running. Does that sound right? By the way it doesn't appear to change the readings significantly if I disconnect the glow plug power wire or have it on. So two questions: Should there be voltage at the power terminal on the alternator with the key off? and, Should there be any voltage drop between the alternator power terminal and the battery terminals when it is idling at 14000 rpm?

LittleBilly21 asked me what the voltage was at the alternator with the battery disconnected. My immediate thought was 0v of course, but I thought I'd check just in case, so I disconnected the battery and measured the voltage at the alternator and sure enough it was 0v. So I reconnected the battery cables and checked the voltage of the battery with the engine off and it was 12.60v and checked the voltage of the alternator (with engine off) and it also was 12.60v. But this time when I started the engine and check both of them, the voltage at the alternator was 14.44v and at the battery it was 14.14v. That is certainly enough voltage to charge the battery now, but is it too high? I'm not sure why the alternator suddenly went from 12.85v output before to 14.44v now. The only thing that I did between those readings, which were about an hour apart, was disconnect the battery and re-connect it.

 

[LittleBill21]

yea, I meant check it running, but whatever.


14.44 is correct. you have/had a issue with the battery cable going to the alternator, i would look it over, clean it up, sand, scrape the connectors, and re attach and check voltages again.

again your battery is fine, as much as everyone else keeps saying its bad. if a battery disconnected holds over 12.5 for 24 hours, its in good shape.


let me make another comment, the alternator cable may not go directly to the battery, it may go to the starter, and the battery may go to the starter as well, you need to trace this or confirm it via wiring diagram. with your pulling and pushing you prolly moved the cable to work. I would look at the positive side of the starter and make sure that is not where your issue is as well

 

[sunandsand]

Agree, the alternator is good. 14.4 volts = happy alternator.

Follow the wires from the alternator back to the battery, it is beginning to sound like that's your problem.

Each cell of a lead-acid wet battery is 2.2 volts, so a six volt battery is actually 6.6 volts, and a 12 volt battery is actually 13.2 volts. You have to have a higher voltage than that so the battery will charge. 14.4 is right on the money.

(Have you tested the battery with a hydrometer yet? You could have a single bad cell.)


Loose wire, abraded wire, corroded wire, go over it like it is your worst enemy and you're going to take it to court ;-)

Best Regards,

Mike/Florida

 

[ns_in_tex]

Agree, the alternator is good. 14.4 volts = happy alternator.

Follow the wires from the alternator back to the battery, it is beginning to sound like that's your problem.

Each cell of a lead-acid wet battery is 2.2 volts, so a six volt battery is actually 6.6 volts, and a 12 volt battery is actually 13.2 volts. You have to have a higher voltage than that so the battery will charge. 14.4 is right on the money.

(Have you tested the battery with a hydrometer yet? You could have a single bad cell.)


Loose wire, abraded wire, corroded wire, go over it like it is your worst enemy and you're going to take it to court ;-)

Best Regards,

Mike/Florida

I remember one time in past, my L4610 alternator quit charging. We took it to the shop and they told me it was OK. Put it back on, then found the wire broken. Can't remember exactly where, but think it may have been only 24" away from the alternator. I think it may have been inside a protective shield.

 

[jimer1972]

My L4610 won't charge my battery. About 6 months ago the alternator went out and I took my tractor to the local mechanic and he ordered and replaced the alternator. All worked fine for 6 months, then after using my tractor for a couple of hours the other day, I turned it off and tried to start it again within a couple of minutes and the battery was dead. I was able to jump start it take it back to the mechanic. He replaced the alternator again (2nd one in 6 months). After getting it back from the mechanic yesterday, I used it for about 2 to 3 hours and turned it on and off 5 or 6 times, then one time it was totally dead again. The battery is 2 years old and will take a charge and tested good. The mechanic said I need to have the RPMs at 2000 to charge the battery and that it could charge as low as 12.5 volts on a diesel tractor. I'm only seeing about 12.6v at the battery at 2000 rpm. At an idle the voltage at the battery is about 11.9 to 12v. The alternator model is 12179N. Is the voltage at the battery to low? Is that the correct alternator? Is there a separate voltage regulator or is that inside the alternator? Any help would be greatly appreciated.

I don't have a Kubota but if you don't need the rpm then I would change the pulley to a smaller diameter size.
You might also do a parasitic test of you have a fuse box. * Disconnect the + cable then put a meter between the cable and battery with ampere setting on. Observe the amps. If there is a draw then start pulling fuses one at a time and see which one (fuse) brings your amp draw back to zero. This will tell you if you have a short somewhere in the system.
If you are still confused Google [parasitic draw].
Good luck