IH 966 Battery Drain

Matt. C · Feb 20, 2011

I have an IH 966 with a battery drain. IH mechanic told me to take off the ground cable and scraped it across the negative post. Did and have confirmed I have a short somewhere in the system. I unhooked the two wire plug and positive cable on the alternator with everything turned off and that stopped the sparking on the ground cable. So I bought two new batteries (old ones were done for after too many drains) and a new alternator. I have installed the new batteries and alternator to find out that even with these items new I still have a drain using the negative post testing method with the alternator wires plugged in. The lights to the tractor are not connected and I have installed a new key switch. Could it be the starter solenoid is shorting out and causing this? What else would have live power with the key off and the tractor not running? Any help or suggestions would be much appreciated.

Moline_guy · Feb 20, 2011

Unless I read it wrong, it sounds like your problem is either in the hot wire going to the alternator or the lead wires going to the alternator to the key. I have had a lot less problems with electricals since I start putting self energizing alternators on my tractors. You can get them at any auto parts store and they eliminate the charging and draining problems of older machinery. Proabably not the answer your looking for, it is just something that I have done over the years. Good luck with it, maybe someone can help you locate the trouble.

Bob · Feb 20, 2011

If the current drain stops when you disconnect the alternator, WHY are you suspecting the STARTER SOLENOID???????????????????????????

What alternator does it have... earlier units had a Delco 10DN with EXTERNAL regulator, later units had a 10SI Delco with INTERNAL regulator.

I'm gonna GUESS you have the 10SI-style alternator, which will look like THIS:

<img src = "http://www.gondtc.com/~blweltin/Bob/AlternatorHarness.jpg">

If does look like the alternator in the photo, IGNORE the wiring shown for now. Can you see the #1 and #2 terminal markings?

#1 is the "excite" terminal and should ONLY have power when the ignition switch is on and/or the engine is running.

The #2 "voltage sense" terminal will have power at all times.

If the connections are reversed or the #1 terminal has power at all times for ANY reason the battery will drain.

Here's a drawing of the older-style 10DN alternator:

<img src = "http://www.gondtc.com/~blweltin/Bob/Delco10DN.JPG">

IH2444 · Feb 20, 2011

Does your alternator have an external regulator?

if so it is a likely culprit.

Janicholson · Feb 20, 2011

It is possible that a bad regulator (if it has one) will make it drain the battery. If it is like the lower of Bob's two pictures, it will have that regulator. Google Delco 10DM wiring. The first listing on my search brings up a great diagram.

New alternators can be bad as well.

See Bob m wiring diagrams for wiring a Delco 10SI internal regulated alternator. I do not recommend the one wire solution. Jim

Switch flicker · Feb 20, 2011

Couple of questions.
Bob. What"s the diode for in the picture? Testing of some sort I"m sure

Jim, why don"t you recommend the single wire solution?

fixerupper · Feb 20, 2011

Did you disconnect the alternator wires one at a time to find the real culprit? Jim

teddy52food · Feb 20, 2011

With the wires off the alt & battery connected, see if there is a draw on the big terminal on the back of the alt. If there is ,it has a diode bad. Did you put the battery in with negetive ground? Check the plug on wires as per the other posters.

Jon Hagen · Feb 20, 2011

Try your battery cable spark test by removing one alternator cable at a time. First remove the two wire plug at the alternator, then check if the bat cable sparks are gone. If the alternator is the type that has the side plug with red wires attached in Bob's picture, make sure that only the one marked #1 on the case, has power when the switch is on. With age and weather, those alternator plugs get rotten and allow the plug terminals to pull out of the plastic, so it is easy to get them on the wrong terminal. If those wires are reversed, it will drain the battery. Any auto parts store has new replacement plug kits for around $2. Replacing it protects your tractor from battery drain or electrical shorts /fires from the alt terminals touching the alt case.
If the alternator has the rear plug as shown in Bob's lower picture, a battery drain can be a bad external regulator under the steering column base, remove the cover plate right at your feet level.(remove the 4 wire plug from the regulator and see if the bat cable sparks are gone), if so , regulator has stick field relay points.

Janicholson · Feb 21, 2011

Three reasons for the dislike.
In all the postings on here, and hotrodding experience (others cars), there is a reliability factor on the re regulated non stock one wire alternators. There are Delco alternators from delco that are fine, But I think they are industrial application and both big, and expensive. The various suppliers have shch dramatic differences in current draw when off, self exciting RPM, and directions, that I shy away from recommendation.
The second reason is that the 3 wire setup is really a 2 wire (the #2 terminal attaches directly back to the alt big stud) the #1 terminal (with diode as shown, or a 15-0hm 10watt resistor, or a idiot light in the wire to prevent the ignition from continuing to be energized which keeps the tractor running if spark ignition)
This is the way the Delco 10SI is installed in the vehicles that used them OEM.
The third reason is they are available in every junk yard cheap. Jim

Kentb of SWMO · Feb 21, 2011

I think the wires in the in the regulator plug are switched. The terminal on the regulator that is toward the BATTERY terminal of the alternator should only have voltage on it with the ignition switch is in the ON position. The other regulator terminal has 12 volts on it all of the time. If the wires are switched OR the plug is damaged so the plug can be installed wrong, this will energize the alternator ALL of time and will cause the battery to drain/discharge.

Kent

Bob · Feb 21, 2011

GOSH I wish I'd have thought to post that!

(Oh, yeah, I ALREADY did!)
Wires could be reversed

Owen Aaland · Feb 21, 2011

Just because you get a little spark at the negative cable with the new alternator does not necessarily mean that there is still is a problem. A system with a 10SI alternator will usually have a little spark when connecting the cable but the draw is so little that it would take years to drain the battery. If you have a spark as large as you did on the old alternator then you may have a problem with the new alternator.

jackinok · Feb 22, 2011

make certain on your alternator,that the feild coil is the one thats hot,or jumped to the battery post.if your looking at it from the back the one on the right will be the feild coil.the one on the left of the two post plug is the one that needs to be switched with key.heres the deal,it will work perfectly both ways,you will see no difference in the charging of the alternator.But it will slowly drain battery if they are backwards.you will also have to add either a light,or diode in the sense wire circuit to stop feedback into ignition.

IH 966 Battery Drain

Matt. C

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Moline_guy

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Bob

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IH2444

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Janicholson

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Switch flicker

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fixerupper

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teddy52food

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Jon Hagen

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Janicholson

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Kentb of SWMO

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Bob

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Owen Aaland

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jackinok

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