B2410 Charging System & Battery Light

[Greasyporkgoodness]

First time post, this is a great site and I’m amazed by the help you all give!

So last fall my battery died so I replaced it. I could hear the new battery it getting weaker and weaker with each start until it was dead as well.

I ordered and installed a new dyno and charged the battery externally. Same issue, battery drains after a few starts. So I replaced the dyno again thinking it was defective. I took the new battery back and it tested as likely bad - so it has another new battery in it.

My battery light is always on, though it has always been on. When I test with the voltmeter I only get ~12.25v. Measuring from the battery or the dyno, same deal, low or high RPM. I assume it should read ~14v as an alternator would.

Im at the end of my diagnostic know how. What do I check next and how do I check it? Starter? Voltage regulator?

thanks for reading and thanks for your help!

-Greasy

 

[wgator]

Sure sounds like your regulator is bad, To check it download the Workshop manual (WSM) for free BY CLICKING HERE .
In that WSM pdf file on pdf page 370 (WSM page 9-S15) is the testing procedures for the charging system.

Edit: Welcome to OTT.

 

[Greasyporkgoodness]

Sure sounds like your regulator is bad, To check it download the Workshop manual (WSM) for free BY CLICKING HERE .
In that WSM pdf file on pdf page 370 (WSM page 9-S15) is the testing procedures for the charging system.

Edit: Welcome to OTT.

Great, thanks a lot - I’ll check that out and report back!

 

[Greasyporkgoodness]

Sure sounds like your regulator is bad, To check it download the Workshop manual (WSM) for free BY CLICKING HERE .
In that WSM pdf file on pdf page 370 (WSM page 9-S15) is the testing procedures for the charging system.

Edit: Welcome to OTT.

Ok I took a look at that section - I dont have a tester, just a voltmeter. So I'll have a look for that tool. However, I did notice that the dynamo should have a 14-15v reading at 5400 rpms. I'm I reading that correctly? Seems crazy that I would have received 2 defective dynos but I suppose it is possible.

 

[Dave_eng]

Ok I took a look at that section - I dont have a tester, just a voltmeter. So I'll have a look for that tool. However, I did notice that the dynamo should have a 14-15v reading at 5400 rpms. I'm I reading that correctly? Seems crazy that I would have received 2 defective dynos but I suppose it is possible.

Save your old dynamo as there was nothing wrong with it. They are so simple internally that failure is rare.

The first mistake owners make is not realizing how to test the dynamo. It produces alternating current not direct current and the proper voltmeter scale must be used. Second, to test the dynamo, its two lead wires must be disconnected. You connect the two leads of your voltmeter to the two dynamo leads. Run the engine at idle and max rpm's and read the voltage.

The 5400 rpm's is misleading as this is the effect of the engine pulley being larger than the dynamo pulley and thus turning it at faster than engine rpm.

The Kubotabooks WSM on page 370 is misleading for all except real tech people. it tells you the volatge to measure but no where does it use the words alternating current voltage. Instead it uses a symbol to show alternating current which means little to most people.

You likely need a new rectifier/regulator.

Doing all the rectifier tests on page 370 will just confirm the need for a new unit.

Dave

 

[Greasyporkgoodness]

Save your old dynamo as there was nothing wrong with it. They are so simple internally that failure is rare.

The first mistake owners make is not realizing how to test the dynamo. It produces alternating current not direct current and the proper voltmeter scale must be used. Second, to test the dynamo, its two lead wires must be disconnected. You connect the two leads of your voltmeter to the two dynamo leads. Run the engine at idle and max rpm's and read the voltage.

The 5400 rpm's is misleading as this is the effect of the engine pulley being larger than the dynamo pulley and thus turning it at faster than engine rpm.

The Kubotabooks WSM on page 370 is misleading for all except real tech people. it tells you the volatge to measure but no where does it use the words alternating current voltage. Instead it uses a symbol to show alternating current which means little to most people.

View attachment 44510

You likely need a new rectifier/regulator.

Doing all the rectifier tests on page 370 will just confirm the need for a new unit.

Dave

Haha I want to go out to the barn now and change my voltmeter setting!! Thank you, I did not know what that symbol meant. To bad I tossed the old dynamo - rookie mistake.

 

[Dave_eng]

Haha I want to go out to the barn now and change my voltmeter setting!! Thank you, I did not know what that symbol meant. To bad I tossed the old dynamo - rookie mistake.

The new dynamo will last a lifetime so a spare is not necessary

Dave