08 kawasaki Mule 600 Not Charging Battery

dalem · November 15, 2019

Earlier this year my battery was weak and I had to boost my mule to start it then I decided to remove the battery to check the fluid level which was very low, I set the levels and recharged the battery a few months later it did the same thing, so I had to boost it again then checked the voltage running was getting around 16 vdc ( which is too high) and fluid level was very low again and wouldn't hold a charge. Note: The battery was maybe 1-1/2 years old. Then I replaced the battery and checked the voltage running nothing changed I was only reading battery voltage it wouldn't increase with increased engine speed. I changed the voltage regulator with an aftermarket one, same thing not charging. I checked the alternator per the service manual which states .3 ohms or less it checks at .2 ohms and not shorted to ground. With the engine running I disconnected the alternator and it had around 22 vac idling and around 60 vac revving the engine, so I figured the regulator was bad so I replaced it with another new one (aftermarket) from a different company, again not charging only reading battery voltage. I did put the original voltage regulator on nothing changed still not charging. Using the manual wiring diagram did continuity checks going to the voltage regulator everything checks out OK. Now what am I missing?

Travis · November 15, 2019

This may sound silly, but are your battery cable ends free of corrosion?

dalem · November 16, 2019

The battery connections are perfect and should be on the positive at the solenoid but I'll check it to be sure. I had changed the starter last year. Now I did not check the negative side to the frame, I will check it out tomorrow. Thanks! I see in your picture you have a 550, I have a 550 also, looks just like yours. They are good utvs also

Travis · November 16, 2019

This one's been going for 19 years. I replaced the rear axle seal and bearing, and pulled th engine, put new rings and seals on it. It's been a good machine with very few problems over the years.

Nate T. · November 16, 2019

Overcharging with a hot voltage >14.5VDC can damage battery cells. You can also get low quality batteries fresh from the store. Your hot voltage may have killed a new battery.

dalem · November 17, 2019

The new battery works ok. I read the same battery voltage running or not. I checked all connections to the battery and grounds all are OK. If I use the lights the battery voltage will drop while its running. Two aftermarket voltage regulators and the original all do the same thing the battery voltage stays the same (now at 12.25 vdc) if I don't use the lights. I just keep recharging the battery(every other week). I use this mule everyday. I'm just wondering would a genuine Kawasaki Regulator make any difference (they are a lot more expensive)

Travis · November 17, 2019

2 things are bouncing around in my mind.... here goes!

1. if i remember correctly the 600 engine uses a stator (alternator) behind the flywheel, on the inside edge of the flywheel are magnets that rotate around the stator as the engine is running and generates AC voltage.

its possible something is wrong with the magnets, but not very likely. Sometimes they can fall off/out of the flywheel, but you would more than likely know if they did.

2. Also, sometimes (i know this is true on some Riding Lawnmowers) they have Diodes in the wires that carry the AC voltage, diodes allow current to flow one way, but not the other. And if they go bad current will not flow through the wire.

im not 100% sure your mule has them, but i figured its worth putting out their incase someone else knows.

Nate T. · November 17, 2019

OEM lights and not LEDs, correct? If that's the case those OEM lights draw a lot of current, probably in the neighborhood of 50w each. The stator on an old Mule isn't that beefy to begin with, so you will get a significant voltage drop when the lights are on. Maybe you don't really have an issue. Or maybe you have a slight short to ground somewhere in the wiring with rubbed through wire insulation.

Travis · November 18, 2019

Yep I replaced the headlights on my mule with 2 small Pod LED s.

Brighter, but less power consumption.

dalem · December 19, 2019

I have stock lights. Nothing added on this Mule. I did see another post with a mule 610 charging problem and she I have the same problem but my 08 Mule 600 calls for a regulator P/N 21033-0010 (5 wire system ) hers a P/N 21066-0039 (4 wire system). Doing a little research this changed in 09 the charging system circuit eliminates the brown wire does anybody know the reason for this. They both have the same 6 pin connector.

Travis · December 19, 2019

I don't know the reason for it, but I'm sure Kawasaki Engineers knew why.

Marcus Yates · March 8, 2021

Where does the white wire on the voltage regulator go on a 08 610 mule?

Travis · March 8, 2021

do you mean where it should plug into the regulator, or where it goes FROM the regulator?

the white wire makes the circuit from the regulator, to the key switch, and it also supplies power to the electrical accessory connectors.

andre57 · March 22, 2022

The white wire is a fused wire from the regulator to the battery and should also connect to the ignition switch. I think the brown wire is from the ignition switch.