very hot -battery cable

[lpakiz]

bgr is exactly right on. In fact, folks who might attempt to troubleshoot a starter or charging system might even want to print out this procedure.

 

[Gord Baker]

Remove and clean ALL battery cable connections. (4). Clean solenoid connections (2).
If the last battery connection sparks when you connect it, leave it disconnected.
Likely bad alternator unless you got a lot of stuff wet when washing at the pond!

 

[Tony H]

Wondering if the insulator between the +12, alternator Stud is misaligned or missing. This would literally cause a direct short to Ground. As it's a remanufactured unit, I'd look there first. Unless you Pond Bath got water someplace that needs time to dry out

 

[JWR]

. Blimey - talk about money to burn!!
Don't buy anything until you have thoroughly cleaned the battery cable connections & the earthing point(s) on the engine & chassis. 10:1 it's just a bad connection. Next thing is to check the cable terminations. If these are bad then just shorten the cable & use new terminals. Only if still bad do you need to go & buy new cables . Have you seen the price of copper these days?

Amen -- after all this discussion no one had yet suggested checking to see if the battery cables were tight on both ends. Have not heard any thing yet from the OP that would indicate a need to buy or replace anything.

 

[KWentling]

bgr is exactly right on. In fact, folks who might attempt to troubleshoot a starter or charging system might even want to print out this procedure.

Absolutely. Voltage drop tests are VERY valuable. Too easy to be fooled by resistance and voltages with no load applied.

 

[Rebeldad1]

You don't say which battery cable. Is it the positive from the battery to the starter solenoid? If the cable ends are hot it is probably a bad connection/corrosion there. If the cable itself is getting hot along its length, you have excessive amp draw. First recheck all wires you touched when doing alternator. Are they in right place according to the book? Always suspect your recent work when a problem occurs afterward.

Voltmeter tests you can do.

1. Put voltmeter leads on battery positive and negative when battery is at rest. Set at 20 volts. Should read over 12.5 v. ignition off, no draw. Turn on key and headlights. Voltage should not drop more than .4 volts. if there is a big drop, battery has a bad cell.
2. Visually check all connections and starter to frame ground to make sure contacts are all good.
3.Turn key to start, should be over 9.6 v. If below that battery has a bad cell or excessive starter draw.
4.Test battery with load tester before going further. A weak battery producing low voltage will cause excessive current to flow to starter and heat up wire.
Battery must be good for rest of tests.
5. Put one voltmeter lead on battery positive and other on end of positive cable where it attaches to starter solenoid. Leave meter set at 20v. range
Crank starter. If voltage is over .2 volts connections are bad. Over 1.0 volt is a bad cable. (You are measuring voltage drop in cable under load.)
6. If Test #5 shows less than .2 volts , leave one voltmeter lead on positive connection at starter solenoid. Put other lead on negative terminal of battery.
Meter should read within .1 volt of battery voltage. Crank starter. If voltage drops to 9.6 volt or less, and battery is good, starter is drawing excessive current.
Take apart starter, make sure lubrication of motor shaft is good, and armature is not rubbing on case or windings somewhere and brushes are free and clean off dirt on brush slides.
If the voltage stays above 11.5 volts or more and starter is slow or won't turn, there is an internal problem in starter.
If no visible problems, take starter to rebuilder.
7. To test ground circuit. Put one voltmeter lead on some metal part of the starter. make sure you have a clean connection. Put other voltmeter lead on battery negative post. meter in 20 volt range. Crank starter. If voltage is over .2 volt you have a bad ground connection somewhere. Make sure starter bolts to engine are clean and tight. Check and clean connections on ground strap from engine to frame. Check and clean end of negative cable where it bolts to frame. Check negative terminal on battery.

Probably you have something wrong related to your recent work or battery has a bad cell, but these voltage drop tests will let you isolate a problem quickly. If you replaced the alternator, I assume the battery was getting low and repeated starting with a low battery draws heavy current and can damage starter or cables.

A bad connection isnt going to cause a draw d own of the battery while sitting

 

[JWR]

A bad connection isnt going to cause a draw d own of the battery while sitting

No but it can cause an overall voltage drop when trying to start. And heating at the bad connection which gets conducted to the cable. The resistance of the cable goes up with temperature too.

 

[Garson]

Wow... sorry to hear that. The solution is a battery disconnect switch. It's common in some things. In fact, it would be rare to find a boat that doesn't have one. It's basic safety and common sense.

But tractors, cars, and trucks rarely have them because they are not operator convenient.

I'm no better. Our boats always had battery disconnects, and so does our camper and commercial equipment. But none of our cars do. And half the tractors don't. Maybe I should make that next year's project.... to put a manual battery disconnect switch on everything.

rScotty

Of course a battery disconnect switch will reset all computers on a car or truck. This switch is best used on lawn mowers, etc that don't have a clock, etc.

 

[Garson]

hi all,, I have a older L275 Kubota ,,I replaced the alternator yesterday took the tractor for a ride also washed it at a pond,,drove it back to the parking spot,,about 2 hours later went to start it and the start would just click...I know the battery is good because I checked it after installing alt...any way I noticed the - battery cable was extremely hot..any body have any idea what is going on? it always cranked fine before is this a sign of a bad starter? your thoughts please...

It sounds like one of your battery cables were hot after the L275 sat for 2 hours. This says that your tractor is drawing current when shut off. My first guess would be worn insulation or a pinched wire on a 12 volt supply cable somewhere, causing a partial short even with the tractor ignition switch off. Or possibly an internal partial short in any device that draws current (including the new alternator).

The two reasons a battery cable would get hot is-
1- Too high a resistance (others here have suggested that it is corroding) but this happens over many years, not after an alternator replacement.
2- Too much current flowing in the battery cable.

Battery terminal connection problems will increase the resistance at the high resistance connection point so that connection will overheat, not the cable (except near the terminal). A different alternator could be leaking current (via an internal partial short) and this increased current would heat a cable and drain your battery quickly when the alternator is not turning.
Considering that your starter is decades old, it is unlikely the starter is causing any current leaking, and even less likely if you were not cranking the engine over when noticing the hot cable. It's most likely you have a cable pinched or its worn insulation is causing leakage to ground. Check all cables you were near when replacing the alternator.

A quick check to verify if you have a partial short on your 12 volt supply cable to the alternator- disconnect this cable at the alternator and also at the battery. Then check the resistance from this cable to ground. It should always be infinity ohms. If that is OK, then you have current draw somewhere else in the system.

I had an L275 for 20 years and loved it. Had zero problems and it was super efficient using very little fuel. You have a great tractor. Hope you get to the bottom of this.
Garson

 

[MountainBuck]

I have an alternative thought on this. Getting the tractor wet is suspicious in the problem, but also the new alternator is suspicious because of the quick onset of the problem.

Alternators make AC and that goes directly into a rectifier to make DC before it is fed to the tractor / battery. The rectifier most of the time is right on the alternator. If one or more of these diodes in the rectifier are (bad / leaking / shorted / open) then weird things can happen like draining the battery and heating up wires.

I'd want to hook up an oscilloscope to the output of the alternator and see if there is pure DC or if there are some AC spikes/ ripples. Unfortunately a simple multi-meter will not pick up things like a rogue AC ripple in DC.