B2910 battery light

[LandHoarder]

I recently purchased a B2910 with 72 inch mid mount mower. I mow around 8 acres of hills and flats with it. I***8217;ve noticed while mowing for 3 hours or longer, the battery idiot light comes on. It will stay on for about 15 to 20 minutes, sometimes longer, then goes off and then back on. Not a flicker. I replaced the belt the first time I noticed it and that kept it off for a while , but it***8217;s back to doing the same thing again. I***8216;ve checked all connections and they are good to go. My question is, is it possible the belt just keeps stretching and I just have to keep readjusting it or is the alternator going bad? Is there a way the test the alternator?

 

[Dave_eng]

You have a dynamo not an alternator from the spec's I can find.

The dynamo is a super simple device which rarely fails. I have attached the test procedure. You need a multi meter which can measure Alternating Current voltage.

Its output is low by design so fan belts will not be involved in what you are experiencing.

The idiot light is turned on by the regulator. Its internal electronics may be starting to fail. Check the battery voltage whenever the light comes on.

Dave

 

[LandHoarder]

Thanks for the info. I will test it the next time it happens and keep you posted.

 

[Henro]

A while back I was using my backhoe on my B 2910, and I noticed the alternator light was on. I figured I would check it later, but the engine overheated. Turns out the fan belt broke.

So my advice would be to change the belt and see if it makes a difference. On mine, at purchase I upgraded to the higher capacity alternator… Not that that means much.

The belt change is easy. Perhaps you can even increase belt tension. Don’t remember the details now, but a quick look should tell you the answer.

Hope this helps...

 

[LandHoarder]

Dave_eng,
The low idle test showed 14.8 and the high idle(2500RPM) showed 31.3. According to the picture that you posted, the high idle is below the test specs. So does that mean that the dynamo is bad or regulator? If it***8217;s the regulator, where is it located or is it within the dynamo?

Henro,
This is happening with a brand new belt from Kubota. When I first noticed it, I went to put more tension on the old belt and noticed that the belt adjustment was at maximum adjustment. Also noticed that the old belt was too long and rubbed a grove in the lower radiator hose. So I bought a new lower hose and belt and replaced both. The light still comes on randomly.

 

[Dave_eng]

Dave_eng,
The low idle test showed 14.8 and the high idle(2500RPM) showed 31.3. According to the picture that you posted, the high idle is below the test specs. So does that mean that the dynamo is bad or regulator? If it***8217;s the regulator, where is it located or is it within the dynamo?
.

The dynamo's output is close enough. Did you test it disconnected? It should be tested disconnected.

The regulator is separate from the dynamo. Look for a rectangular box with fins for cooling. About 2" x 4" x 1.5" thick.

See photo from Messicks attached.

Their parts page shows a serial number break so be careful should you decide to order one.

Make certain the present regulator;s fins are clear of dirt and debris. If it cannot get rid of heat it can produce the symptoms you have.

Dave

 

[LandHoarder]

Re: B2910 battery lighting

Yes it was tested disconnected. I***8217;m try to locate the regulator/rectifier. It appears to be behind the dash/cowl and I will have to look for it later. I also did at test at the battery while running at 2000 RPM and only had 12.1 volts. Thanks again for all of your help.

 

[LandHoarder]

Well after pulling the regulator out, I located what I think is causing the problem. The plug on the regulator and the wire harness are both partially melted. The black wire in both plugs is what melted. I will get a new regulator but Is there a way to purchase a new plug end for the main wire harness or do I have to use spade connectors and eliminate the plug.

 

[Jim L.]

I will get a new regulator but Is there a way to purchase a new plug end for the main wire harness or do I have to use spade connectors and eliminate the plug.

google nylon six pin connector. Match up gender, lug sizes, dimensions, etc. Places to look are amazon, motorcycle repair, motor sport, japanese connectors, etc.

 

[Dave_eng]

Well after pulling the regulator out, I located what I think is causing the problem. The plug on the regulator and the wire harness are both partially melted. The black wire in both plugs is what melted. I will get a new regulator but Is there a way to purchase a new plug end for the main wire harness or do I have to use spade connectors and eliminate the plug.

The black wire(s) are the regulator ground and are joined to other circuits such as lighting also providing a ground for them. Make certain the black wire does have a good ground. Connecting it to the point where the battery ground cable attaches to the engine would be a good step to ensure the entire ground circuit is strong.

My inclination would be to buy a new regulator and eliminate the plug completely. They are only used for the initial build and replacement but are also a weak point in the system.

Cut the plug off the new regulator.

Best would be to solder each wire together and cover using heat shrink tubing.

High quality crimp connectors are second best but again cover with heat shrink.

Dave