Help Fix Parasidic Drain Down of TC55 Battery

[edge08]

Hello, I am hoping someone here can advise me on the best way to run down my electrical problem that is causing the battery on my TC55DA with PIN above HX11752 to run down within minutes if the tractor is left idle. I believe I have a 55 AMP alternator according to the instruction manual. The problem had a gradual onset. First I notices starting was a bit sluggish and then my battery went dead. Thinking the original batter was just old I replaced it only to find the new battery would go dead as well. So after doing some reading I put my volt meter inline with the negative terminal disconneced and started to check components. I've pulled all the fushes individually, the two conrollers under the dash, the Glo plug regulator, key switch, seat switch and each of the plugs on the alternator in turn each time checking for a voltage leek inlne with the negative battery cable. I've disconneced the wiring harnesses going from the dash under the tractor fender and nothing I've check seems to stop the leek. I could not find a "voltage regulator" on this tractor. The only thing I haven't pulled was the starter because it looks a bit time consuming to disconnnect and it does start the tractor as long as I've charged the battery and then it runs normally with no indicator lights on the dash. When I tested the system with my battery charger for alternator function running it is reading faulty but I'm not sure if I'm using the charger right or if a parastidic leak somewhere else in the system like the starter is causing a fault reading. I simply hooked my charger to the started tractor and pushed on and check alternator, then it gave a fault code. However, because disconnecting the alternator termials one at a time still indicated a voltage leek I'm not positive it's really the problem.

Nothing I have disconneced got rid of the leak. When I start the tractor there is only 12.7 volts across the batter terminal and I show a 10 volt draw when the tractor is off. One guy I talked to suggested that there is a switch open that is telling the system the battery is charged bypassing it when it's running and allowing the current to flow out when the tractor is off. It also may be robbing the starter of current making starting a little sluggish.

Can the starter be defective and still work with a charged battery or does this sound more like an alternator diode problem? I'm frustrated and need someone to help focus my attention at the most obvious problem area. Thanks for your help!

 

[Smallplot]

Couple of quick questions.

When you put the new battery in did the problem start immediately again or did it take a while to begin? If problem took a while to develop it could mean a bad battery.

After you shut down the tractor, if you unhook the battery, does the battery show any charge remaining? after sitting a day or two is there any difference in the charge remaining? May need to take the battery back to where it was purchased or somewhere and have it load tested? I have gotten new batteries that were no good but a load test is needed for conformation.

If you rule out that the problem is not with the battery the next place I would look would be the alternator. You should be able to pull it off and take it to your dealer and have it bench tested. The dealer should be able to tell what is wrong with it during the bench test.

 

[Soundguy]

pull hot cable, insert test lamp for visual cue. a drain that kills the battery within minuts must be hundreds of amps.. so I'd start with things like starter and starter relay lines, and next glow plug.. etc. pull 1 line at a time and watch that lamp.. procede to charging circuit next, then to fuses, 1 at a time.. relays.. etc.. etc. then lamps.. etc.. etc..

soundguy

 

[edge08]

If I unhook the battery immediately after using the tractor it will restart if I hook up the battery and immediately start it up. The new and old battery will take a charge if not hooked up to the battery terminals. I bought the new battery because the charger was reading fault before I unhooked the battery. Thankfully I traded in a really old dead battery and kept the tractor battery for other equipment where it is needed. I feel like there is some hesitation starting even after the battery sits charging for hours but it turns well enough and starts. The reason I was thinking defective alternator was that the battery terminals only read 12.7 volts when running. I thought it should be about 14 volts but it is more than 12. Maybe a starter relay is staying on and drawing a lot of current from my electrical system. The lights are a bit dim when the tractor is running. I don't know if a voltage leak in another componenet would cause such a drastic drop of voltage at the battery terminals but I don't have enough experience fixing electrical problems to be sure.

I need to ask. If the starter or a component in the starter goes bad, will it still turn and start the tractor with a fresh battery or is that a false test for a starter based voltage leek? It is the only component I know of that I have not yet disconnected because it wasn't an easy thing to unplug. I don't want to take the time and expense to change out the alternator if my problem is within the starter. Thank you for your guidance, further suggestions are appreciated.

 

[kebo]

The proper method to find the source/cause of a parasitic loss of the charge on your battery is not with a voltmeter, but with an ammeter. This is because all the (+) wires are basically in parallel with the source, so in theory they should all measure about the same voltage, less the voltage drops due to wire resistances, terminal connections, etc.

However, the procedure to measure the current can be messy. By that I mean, in order to make measurements the standard ammeter has to be in series with the circuit you want to test. This means that you have to open the circuit to measure any current flow through it with a standard ammeter. Now there is another option, if you have access to a DC ammeter with a clamp on probe. That should work without breaking each circuit to get in series with it. Without a clamp on style meter, then either take the wires loose wherever you can, or simply cut them, take the measurement and then splice the two ends back together. That's the "messy" part of it, no one want's a bunch of wires spliced together on their tractor.

The basic steps would be to try and measure the current flow through each circuit (every (+) wire tied to the 12VDC source that goes to *some electrical component*), record each one, and then you would have a picture of where the current is going with the keyswitch off. So, which ever circuit (wire) that you find to have the highest current measurement should lead you to the source of the parasitic drain on the battery. That fact that you measure 10VDC with everything off means the load is dropping the battery about 3VDC. That's a pretty good load.

I can't answer the question about your starter. There's only one way to eliminate it as the source of the parasitic load. Disconnect it and see what happens! My guess is there is some little circuit (a wire going somewhere) you have missed and it may have a chafed (bare) spot that is giving a high resistance short to the metal frame, or something along those lines. Also, if the "chafed area" was in *front* of the fuses, or the components you already disconnected, pulling fuses or disconnecting those components won't have any effect!! So, keep that in mind.

A quick (and temporary fix) would be to install a master disconnect switch so you could disconnect the 12VDC cable from the (+) terminal on the battery, when the tractor is not in use. That would at least let you use the tractor without having to charge it every time you needed it, while you were trying to diagnose the source of the problem. Good luck.

 

[edge08]

Well I think I've isolated my problem at the starter. I cut the zip tie and dissconnected the termial leading to the side post and the drain from the battery stopped cold. I tried my meter in series and full voltage was flowing through the red wire. ding ding ding ding ding...........

Now I need help with the repair. Is this the high voltage circuit that is activated when the key is switched to the on position for starting? I know not all the starter current goes through the switch. Do you think the problem is in the regulator of the starter and can I just switch out the regulator? Does the entire starter have to be removed or can the regulator be changed out without pulling the stater off the engine? This is a japanese made Denso starter.

I should add that when the tractor is off there is no sound of the starter spinning even though current is flowing. I've read one reference that said cracks can occur in the stud insulator that shorts with the case. This or a sticking plunger may be causing my problem.

 

[kebo]

I don't understand what you mean by, "my meter in series and full voltage was flowing through the red wire"?? If the meter was in series, then you would be attempting to measure current, not voltage. If the starter is indeed the source of the parasitic load, you should measure almost no (or zero) current flow from your battery with the starter disconnected. Also, the voltage should go back up to 13VDC. Usually devices such as digital clocks/hourmeters and the memory in your radio will draw a very small amount of standby current, but I don't know if your tractor has those features.

Perhaps you meant that when you disconnected the starter lead, the battery voltage went back up to the normal 13VDC?? If so, then you have almost certainly found the source of your problem.

As for what is wrong with it, and how to go about fixing it, not sure I can help you with that. If the plunger were sticking, then why would it work normally all of a sudden when you go to crank it up? I think that alone rules out the plunger.

Take your ohmeter and measure the DC resistance from the 12VDC connection point of the starter (with the wires from the battery disconnected) to its metal case (ground basically) and see what it reads. If there is a short it will be a very low value, probably less than 50 ohms or so which would be considered a high resistance short. If it reads something less than 10 ohms, that is pretty much a dead short somewhere. If you can't find the problem right off, it may be best to take it to an alternator/starter shop and let them take a look at it.

 

[Soundguy]

to the OP.. be a lil more clear. the starter should have a heavy gauge cable going to it that is always hot from the battery, and then it will have at least 1 smaller diameter cable, though perhaps still something like 8awg or 10awg coming from the wire harness.. sometimes there are others as well. one of the smaller wires will be from the spring loaded start side of the key switch ( thru some safety switches no doubt )..

some designs also put the wire feeding the laod center on that bat hot side of the start solenoid.

which wire did you find was shorting to ground? big wire to bat, or perhaps the heavy wire to the load center / or perhaps from a charge device. I don't have a wire diagram for your machine .. etc.

soundguy

 

[edge08]

Sorry, but I'm not the best eletrician. I have a hard time working with my multimeter without blowing the fuse which I've done before. I think it was the 10 guage wire going to the positive post of the starter that was showing a voltage flowing through when I disconneced the plastic wiring plug and put my voltmeter in series. Current flowed right through indicating to me there is an open flow to the starter with the key off, tractor not running. I'm thinking I have a stuck plunger or a short in the post insulator to the case. I am going to take the starter to my local auto parts and have them bench test it. I suspect it will test defective. I think I can get Denso starter selenoid parts for Christler mini vans and toyotas locally and will try rebuilding the starter solenoid. I found some good instructions with pictures online. When I've had problems with starters in the past on cars I've just swapped them out but I don't want to trade in my current starter for one of unknown vintage. My tractor only has about 400 hours. If the starter motor hasn't been stuck on and spinning or the teeth all chipped up on the starting gear I think I'll be ok. I'm hoping a parts kit with contacts and insulators + a plunger will come in under $50................ My time.......... priceless.........

 

[Soundguy]

see.. there is an issue with your terminology.

ammeters measure in series.. volt meters measure across. when you pull a hot wire off a grounde dload and stick a voltmeter inline.. all you are doing is literally checking voltage potential to ground ( thrut the load ).. etc.

soundguy