Weird (?) battery or electrical system problem.

[bill333]

1991 Ford 1220.

Turned key. One click, then nothing. No instrument lights.

Tested battery. Read 10 volts, failed battery load test. Battery is reasonably new (2 years old, kept on a trickle charger). Specific Grafity tested very good.

Charged battery for 3 days at 2 amps. Read 12v volts, passed battery load test.

Turned key. Same as the first time, one click, large spark from positive battery terminal. Then nothing, no lights.

Here's the weird thing. Immediately retested battery. Reads 8 volts, fails battery load test again. SG is still good.

Something wrong with the battery?

Checked all connections (except safety switches, that's next).

I don't exactly know how to do the 'solenoid/starter' bypass.

From the somewhat hard to fathom wiring diagram, it appears that the relay is connected to the positive terminal of the battery via the starter? Should I be seeing voltage at the red relay wire? (I don't).

Ignition switch looks clean, but again, the wiring diagram I makes it a little difficult to figure out what wire does what.

 

[fried1765]

1991 Ford 1220.

Turned key. One click, then nothing. No instrument lights.

Tested battery. Read 10 volts, failed battery load test. Battery is reasonably new (2 years old, kept on a trickle charger). Specific Grafity tested very good.

Charged battery for 3 days at 2 amps. Read 12v volts, passed battery load test.

Turned key. Same as the first time, one click, large spark from positive battery terminal. Then nothing, no lights.

Here's the weird thing. Immediately retested battery. Reads 8 volts, fails battery load test again. SG is still good.

Something wrong with the battery?

Checked all connections (except safety switches, that's next).

I don't exactly know how to do the 'solenoid/starter' bypass.

From the somewhat hard to fathom wiring diagram, it appears that the relay is connected to the positive terminal of the battery via the starter? Should I be seeing voltage at the red relay wire? (I don't).

Ignition switch looks clean, but again, the wiring diagram I makes it a little difficult to figure out what wire does what.

Take battery out, and take to auto parts store for THEIR load test.

 

[Shaneard]

Sounds like your battery has a cell going bad in it, time for a new one even though it's only 2 years old.

 

[GAFarmer2]

Not a battery expert, but it sounds like the battery has "dropped a cell". Had it happen to me last year with a 3 month old battery on the 240. Have you got another battery you could try?

 

[Ford850]

Other than the large spark from the positive battery terminal, it sounds like a classic bad cell as mentioned above. But why was there a large spark? Were all terminal connections clean and tight? Are there any bare areas rubbed on the cable?
I'd also test the charging output on the tractor. A weak charging system stresses a battery and causes early failure.

 

[buickanddeere]

Keep messing with that failed battery and you may hear a very loud Ka-Boom.

 

[Johnny g]

Keep messing with that failed battery and you may hear a very loud Ka-Boom.

Bin there, done that, the Ka- Boom is VERY loud.

 

[fried1765]

Bin there, done that, the Ka- Boom is VERY loud.

The OP should definitely wear safety glasses!
He will likely redefine the term "acid bath".

 

[bill333]

Thanks all.
All the connections are clean and tight. I can read the full battery voltage at the starter to ground, so both cables appear okay as well.

Won't mess with the battery, but am kind of surprised that when I did charge it, it read a full 12 volts and handled a tester load? Could it still do that with a bad cell?

I can pull a battery from my other tractor to try, pain in the butt as that is.

Edit: Even at 10 volts and a bad cell, shouldn't I at least see (dim) lights on the instrument panel?

 

[fried1765]

Thanks all.
All the connections are clean and tight. I can read the full battery voltage at the starter to ground, so both cables appear okay as well.

Won't mess with the battery, but am kind of surprised that when I did charge it, it read a full 12 volts and handled a tester load? Could it still do that with a bad cell?

I can pull a battery from my other tractor to try, pain in the butt as that is.

Edit: Even at 10 volts and a bad cell, shouldn't I at least see (dim) lights on the instrument panel?

Wouldn't the best/most simple choice be to just pull the battery out of the tractor that won't start, and take it to an auto parts store for them to test?
Can't be too far from an auto parts store in Northern VA.