312-8 battery dies once a month

[2bcross3 1]

This horse sees about 30 hours of operation a month and gets started up about every other day. The battery issue has been happening for about a year. Go out start it up and notice a slow starter, and the next time or two there's not enough in the battery to start the motor. The battery is 2 years old and takes a charge no problem each time it goes dead. Can't seem to figure out why I start loosing battery power. Ideas?

 

[Racinbob 11,888]

it's hard to pinpoint without a little more troubleshooting. The first thing I'd check is the charging system. Check all the connections. Is it really charging the battery fully? It there something that continues to draw the battery down with the tractor shut off? Posting the year you have would help.

Edited October 7, 2014 by Racinbob

[WH nut 553]

Wouldn't hurt to do a started draw test also

[2bcross3 1]

Its a 312-8 with a M12 motor built in 87 (guessing somewhere around there) 

As far as I have found looking over it there isn't a draw when its off, but not sure how to measure if there is actually a draw

I do know there is a loose ground(?) because the seat switch will only work sometimes but can't find where the circuit is being broken. Also I had to run a wire on the ignition switch to chassis ground a few months ago because the switch broke and couldn't shut off the motor.  

[Racinbob 11,888]

Since you have some wiring issues I would strongly suggest downloading the wiring diagram from the manuals here. Go through the tractor and get everything corrected and make sure the connections are good. Trying to troubleshoot an issue when there's known other issues can really be a nightmare. If you're not real strong in electrical don't let the wiring overwhelm you. Take it one step, one wire at a time and you might be surprised to find that it isn't really complicated. Who knows, you might solve the problem just by getting the wiring straightened out. You can check the current draw with a multimeter with DCA capabilities. Don't fret, folks here will help walk you through it.

[Save Old Iron 1,571]

Check 3 voltages

 

battery at rest =

 

battery volts while cranking =

 

battery volts while running =

[2bcross3 1]

Started checking and cleaning all the electrical connections today and got about halfway done. So far didn't notice anything that would cause problems.

I'll check those voltages out tomorrow.

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[2bcross3 1]

Well I finally went to the "manuals" section and was amazed at what I found. I have the original manuals from when the tractor was bought and thought I have have that stuff no need to go look, was I wrong. I now know that I have a 1987 21-12K804 with a Kohler 301. And yep there's a slight difference between 86 and 87. So thank you for saying to go check out the manuals section on here. Learned a bit about my horse.

 

Not a lot of time yesterday but found a dangling wire off the "Test Switch" which went to the PTO switches, oil, seat, and all the rest. Wiring diagram says it goes to a relay then to oil which had me running in circles.   But took the battery out to find a rusting plate, had to clean and paint that first  . After pulling the Test Switch and cleaning a few years of grim off that I found another wire(yellow) on there corroded and about to fall off and had been repaired before. So today I'll be slapping that battery back in place and doing those voltage checks. 

[Jerzguy2 23]

Since I have the same tractor and don’t want to burden anyone yet with questions, guess I’ll just follow this thread. I have no idea how to troubleshoot this tractors electrical system.  My tractor started with the switch when I first got it, but for the last 2 years I’ve had to turn switch on and use jump box to starter to start. Didn’t want to spend $35 on a switch to find out it wasn’t the problem. It’s time to fix the issue.

[2bcross3 1]

Battery test

Batt (rest)= 12.11

Batt (cranking)= 10.42

Batt (run)= 12.02

Looks like there's a problem with the charging circuit?

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[Save Old Iron 1,571]

Battery test

Batt (rest)= 12.11

Batt (cranking)= 10.42

Batt (run)= 12.02

Looks like there's a problem with the charging circuit?

Sent from my SCH-I545 using Tapatalk

Batt (rest)= 12.11            battery not fully charged

Batt (cranking)= 10.42    battery has good capacity

Batt (run)= 12.02             charge circuit not working

 

next step is engine off - ignition switch in run

meaure voltage from battery [-] to B+ terminal on regulator

[2bcross3 1]

next step is engine off - ignition switch in run

meaure voltage from battery [-] to B+ terminal on regulator

=That measures 12.08v

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Edited October 9, 2014 by 2bcross3

[Save Old Iron 1,571]

batttery appears to be connected to regulator -good

 

next step is engine running at full speed

measure AC volts at the regulator AC terminals - place [+] meter lead on one AC terminal and the other [-] meter lead on the other AC terminal

 

stator AC output = ?

Edited October 9, 2014 by Save Old Iron

[dcrage 630]

Chuck

 

If it isn't too onerous would you elaborate on you 'decision tree limits and rationals' for each of the measurements that 2b is giving you -- This looks to be a really good "real life" example

[Save Old Iron 1,571]

my pleasure - will do - later tonight

[Save Old Iron 1,571]

Dave, instead of sidetracking this thread, I will start a separate post regarding the "logic" behind troubleshooting the charge system. I think its overdue and should be of some value instead of repeating the same advice over and over 

 

as I said before, it's only fun the first 500 times you do it !

[2bcross3 1]

I want to say I appreciate this help and so does my tractor. I finally took the engine covers off yesterday and cleaned out 10 or so years worth of dirt from under there. I can see the coil now. Oh what does that say air gap .010 ??? Yep that's more like .025 ---- Should I set that air gap to .010 or leave it be? I can't find anything in the manuals that calls for a spec on the coil air gap but the coil itself has it stamped on it. Having a larger air gap retards the timing a bit correct? 

 

Stator AC output = 36.0vac

[Save Old Iron 1,571]

 

Stator AC output = 36.0vac

 

 

Stator is working fine.

 

Input to the regulator (36 volts AC) is good.

The output from the regulator is currently too low or non existent

 

last step before replacing the regulator will be to place a jumper wire from the case of the regulator to the battery [-] terminal

if the output of the regulator does not rise enough to provide 13.8 volts to the battery, a new regulator assy will need to be fitted to your tractor.

 

the excessive magneto gap should be corrected

Edited October 10, 2014 by Save Old Iron

[2bcross3 1]

Well when I first started it up it read 13.8v at the battery and then dropped to 12.02v in a matter of a second. Rechecked the jumper tightness and even wiggled it around while measuring and still solid at 12.04v

Is there anyway to repair the regulator or is it completely sealed?

I'll get that air gap on the mag straightened out too.

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[Save Old Iron 1,571]

Make sure the wiring and terminals at the regulator connector and the ignition switch connector are clean and free of corrosion.

 

If you are satisfied intermittent wiring or connections are not the issue, replacement of the regulator is the only viable option.

 

I have tried to repair obvious issues with regulators

 

 

 

 

including corroded terminals

 

 

 

 

and cold or fractured solder joints from connector flexing over the years

 

 

Edited October 11, 2014 by Save Old Iron