Battery Overcharging

S

South

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L245DT
Feb 22, 2011
50
1
8
ohio
L245DT. Charge light stays on with key in first position.
New battery, new voltage regulator.
With engine running and key in starting position voltage at battery posts slowly climbs to over 17 volts.
When switch to off position, voltage drops back to just battery voltage.

New voltage regulator made no difference.

thoughts?

Thanks
 
85Hokie

85Hokie

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Check GROUND - after that - check GROUND again, I 'll bet a cold one.......a bad ground!
 
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Dave_eng

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I agreed with 85Hokie's suggestion re ground connection.

If that does not solve the problem, suggest you provide more history on what lead you to start replacing battery and voltage regulator.

Where did you buy the new voltage regulator? The original equipment regulator was a mechanical style with contact points. Is that what you bought?

Please describe the multi meter you are using. What scale do you have it set to if not auto ranging.

Please post a photo of the top of your new battery and also of the back side of the alternator.

Dave
 
S

South

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L245DT
Feb 22, 2011
50
1
8
ohio
Dave_eng said:
I agreed with 85Hokie's suggestion re ground connection.

If that does not solve the problem, suggest you provide more history on what lead you to start replacing battery and voltage regulator.

Where did you buy the new voltage regulator? The original equipment regulator was a mechanical style with contact points. Is that what you bought?

Please describe the multi meter you are using. What scale do you have it set to if not auto ranging.

Please post a photo of the top of your new battery and also of the back side of the alternator.

Dave
Click to expand...
Battery was 13 years old and wouldn’t crank engine without a jump. before I pulled it, I checked voltage to battery with engine running. MM set on 20 v and was showing 17 volts. Pulled battery and had it tested, would hold charge but would drop off significantly when load applied. Replaced VR with same make and model, and yes it’s the mechanical style.
 
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GeoHorn

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Its a vicious circle, but mechanical voltage regulators require a healthy battery in order to function properly. So..if your battery is problematical...replace it... or a new VR will still misbehave.
 
Dave_eng

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I am curious to see what battery voltage you read with multi meter set to measure AC voltage.

If a diode or more are gone in the alternator, it could be that some AC is leaking out confusing DC voltage readings at the battery.

Dave
 
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Thunder chicken

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^ Dave, we had this happen to an airplane one time.... in the bush... over a radio phone the mechanic walked an 18 year old through the troubleshooting to a loose diode. Propane stove, hot nail and a bit of plumbing solder seemed to fix it up and I believe it ran the rest of the year with that repair.
 
S

South

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L245DT
Feb 22, 2011
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8
ohio
I checked voltage at alternator terminal connector, at E and F, with switch on and got nothing...which I take to mean the voltage regulator isn’t getting any juice.
 
Dave_eng

Dave_eng

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South said:
I checked voltage at alternator terminal connector, at E and F, with switch on and got nothing...which I take to mean the voltage regulator isn’t getting any juice.
Click to expand...
Sounds like the alternator is faulty.

If it is where is the 17 volts coming from?

Dave
 
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lugbolt

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weht through this on an older tractor a while back with external regulator

check ground (voltage drop test is best). Ok? Continue

On your voltage regulator there are usually 5 wires. One is ground. One goes to the battery or starter Feeds the battery). One goes to ignition switch to "turn on" the regulator and to provide it with a voltage, for it's sensing circuit. 2 go to the alternator, and are usually the same color (always ac voltage).

On the one I messed with, found ground was fine. 0.08v drop as I remember. Two ac wires were great. My thought? Regulator's bad, replaced. NOPE, still goes to 17v+. With the engine running and me scratching my head, decided to check voltage at the battery wire at the regulator by backprobing, it was fine at exactly batt voltage (also did a drop test). BUT the problem lied with the ignition wire, it was not getting +12v from the ignition switch. Well it was getting voltage but not enough. Found that the wiring was faulty. I ran a separate wire from the switch to the regulator to test, voila, 14.2v rock steady. I ended up removing the wiring harness from the machine and then repairing the old wiring--only choice as a new harness was NLA.

understand how your system works and you'll find it quickly

old kubota rep used to call it the "ah-ha" moment. LOL. He was a funny jerk at times.
 
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S

South

Member

Equipment
L245DT
Feb 22, 2011
50
1
8
ohio
lugbolt said:
weht through this on an older tractor a while back with external regulator

check ground (voltage drop test is best). Ok? Continue

On your voltage regulator there are usually 5 wires. One is ground. One goes to the battery or starter Feeds the battery). One goes to ignition switch to "turn on" the regulator and to provide it with a voltage, for it's sensing circuit. 2 go to the alternator, and are usually the same color (always ac voltage).

On the one I messed with, found ground was fine. 0.08v drop as I remember. Two ac wires were great. My thought? Regulator's bad, replaced. NOPE, still goes to 17v+. With the engine running and me scratching my head, decided to check voltage at the battery wire at the regulator by backprobing, it was fine at exactly batt voltage (also did a drop test). BUT the problem lied with the ignition wire, it was not getting +12v from the ignition switch. Well it was getting voltage but not enough. Found that the wiring was faulty. I ran a separate wire from the switch to the regulator to test, voila, 14.2v rock steady. I ended up removing the wiring harness from the machine and then repairing the old wiring--only choice as a new harness was NLA.

understand how your system works and you'll find it quickly

old kubota rep used to call it the "ah-ha" moment. LOL. He was a funny jerk at times.
Click to expand...
Found it. After studying wiring diagram and comparing it to the tractor, found wire that supplies voltage to the regulator had broke at the key switch. Crimped a new terminal on and attached to switch and bingo.
 
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