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RandyP

K301 charging question

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RandyP
I love this site. To think there are a slew of people around the country who like their tractors as much as I do. :) I have an A/C 912H. The battery is not charging. The ampmeter showed intermittant charging before it stopped completely. I went through the informative steps on Kohler charging system troubleshooting on this site and here's what I get: ~35 volts coming from the stator ~15-18(?) DC volts coming off the regulator with the battery connection disconected However, once I make the connection from the DC out to the appropriate plug, the voltage dropps to battery voltage, with no charging. This would indicate to me that the regulator is toast, it has voltage but doesn't have any amperage to supply the battery. I don't want to just buy a $40 regulator if I'm not sure that's the cause. Here's what I did so far: -Replaced the battery (not for trial & error - I left the keyswitch on for over a week) -Replaced connectors to ampmeter -Sandblasted the crud off the keyswitch terminals and the plug. I'm sure that's not the best way to clean terminals, but now I know it's bare metal on bare metal. -recrimped new spade connectors for the regulator plug -checked resistance of that +12V DC wire from reg through to battery Anyone reasonably sure the regulator is toast? Thanks for the help, Randy Peltz

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Al
Hi, It sounds to me like the regultor is toast. I would replace it the is a very slim chance that is not it, but with the data you have I would replace it.. Good luck, Al We have a regulator tester for these, it is a Kohler item and your local Kohler dealer may have one. We test them at no charge, if they are bad we expect to sell the new reg, or then we charge for the testing if they get the reg elsewhere..

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RandyP
I replaced the regulator ($38), and it charges like it should. Thank you to Simpletractors for the awesome Kohler charging troubleshooting page on this site! I didn't waste any money replacing items with a "trial and error" type of repair. :) One other question: I wanted to confirm the bad regulator analysis by trying the old automotive trick of testing for a bad alternator. On a car, pop off the battery lead and if the alt is working, the engine continues to run. On the tractor this does not happen. I know the system is charging now so I'm not too concerned, but I can't figure out the logic behind this behavior. The reg is putting out 12v, so why does the battery have to be connected? Randy

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Al
Hi, The old car test was common with generators and some of the early alternators that had mechanical regulators. The newer solild state regulators can't stand the transient voltage splikes that occur in the alternator when the battery cable is removed while the unit is charging. A very good way to blow the regulator, or the car computer in a car that has the regulator in the computer instead of the alternator. I cannot wmphasize enough how the new alternator cannot stand running the engine while disconnecting the battery cable. We rebuild alternators in our shop and the days of the the 39.00 and 59.00 alternators are gone. These new alternators can run from 100 to 400.00 for a rebuilt unit. So few are made in the USA any more some can be a problem getting parts for. Some are made in countries we have never heard of. As a result it is important that you treat them well. Do not remove the battery cable when they are running. My 2 cents worth and it is free, value accordingly. Al Eden

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powerking_one
Randy, The reason you can't get any output from the regulator without the battery is the feedback/regulator sense circuit in the regulator needs to see a minimum of 6 volts at the B+ terminal for it to turn on any output. Once that is statisfied, then the internal bias target voltage( 13.8-14.7 volts--factory setting range) is maintained at the B+ wire. Once the battery voltage reaches that setting, output is reduced to 1 or 2 amps (fully charged). Charging on, Tom(PK)

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RandyP
Thanks guys, good info. I'm glad I didn't kill the new one so soon, and I'll be putting on new battery terminals so I don't risk the connection being broken. I'm sure we've all had battery terminal connectors that were still loose after being fully clamped... On a different note, I've been feeling nostalgic lately for the old Farmall Cubs I grew up with (both my uncle and grandfather had them), so I am bidding for one on Ebay. Though I'll probably pay too much, I can't wait to hear the sound that old four cylinder makes under a load. :) :)

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RandyP
Someone here was looking for the bad regulator I replaces so he could disassemble it and check it out. I thought I threw it out, but I found it today. If you still want it, just let me know. Randy

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