Landlord 101 - Briggs 243431 - Starter Generator Overcharging

[Landlord101]

Hello all,

My tractor was giving me a hard time starting (due to a fuel issue it turns out) and I did quite a bit of cranking in the troubleshooting process.  I was concerned I had run the battery down at one point so I hooked it up to a charger.  After almost an hour it was still taking like 10 Amps.  Hmm.

Now when the engine is running at mid-high RPM my ammeter is indicating charge of well over 10 Amps.  Normally it would drop down to zero or near that once the engine was running for a few minutes.  I noticed it reading high like this after mowing for about 10 minutes, and the starter generator was HOT - so I stopped and let it cool off.  Checked that it is not charging with the field disconnected from the regulator, which indicates that the field isn't grounded inside the gen.  So I have to believe it's the regulator.  I have a new one on order from Rare Electrical.

Question is could charging the battery in the tractor with everything hooked up fry the regulator?

Thanks

[Chris727]

I don't know the answer about charging with everything connected, but have you taken a voltmeter and checked the voltage across the battery terminals when running or you're going strictly by the ammeter readings? 

[Landlord101]

Going strictly by the ammeter, which has always worked reliably.  Certainly the hot generator indicates a lot of current flowing.  But I'll check voltage with it running later today.

[Landlord101]

OK so before starting, battery was reading 12.4 Volts or so.  Running at medium-high RPM it's reading about 14.8-15 Volts.

[GregB]

Pretty sure the correct regulator is a current limiting style regulator. 

So that if a bad or marginal battery is asking for a charge you do not "cook" the windings in the generator letting out the magic electrical smoke.

 

There was an article about the system here at one time.

[Landlord101]

40 minutes ago, GregB said:

There was an article about the system here at one time.

Yes, in the Tech Tips forum there's this topic with a (still good) link to the old service bulletin.

 

Edited July 19, 2024 by Landlord101

[GregB]

This is the one I was thinking about.

 

https://simpletractors.com/articles.html/articles/electrical-systems/troubleshooting-the-briggs-starter-generator-system-r14/

 

[Landlord101]

That link does not seem to work.

[PhanDad]

The link referenced above is in the Articles forum and I think you have to be a paying member to access that forum.  You should consider joining to gain access to the full site - definitely worth the $10 for a year. 
 

That said, the article was based on Al’s posts in this thread:

https://simpletractors.com/forums/topic/570-startergenerator-gen-light-on

 

 

[Landlord101]

6 hours ago, PhanDad said:

The link referenced above is in the Articles forum and I think you have to be a paying member to access that forum.  You should consider joining to gain access to the full site - definitely worth the $10 for a year. 
 

Thanks for letting me know - paid for membership and certainly well worth it!

[Landlord101]

I just checked the battery to make sure it wasn't bad.  New-ish Duralast Gold 500 CCA, about two years old.  With the tractor ground terminal disconnected, I put the charger on it, and it behaved like a good battery - charge current dropped off to a few amps after a half hour or so.

I can remove the VR and open it up to take a look for any visual problems - bad contacts or obviously burned windings.  I'll have a replacement unit next week to swap in - a somewhat expensive and time consuming troubleshooting method, unless someone knows of a procedure for electrically bench testing one of these (three unit) regulators.

[PhanDad]

5 hours ago, Landlord101 said:

Thanks for letting me know - paid for membership and certainly well worth it!

Make sure you visit the Download Forum - there’s lots of great print material there in pdf format including some service manuals. 
 

[Landlord101]

Wow yes, the Download Forum is sure packed with good stuff!  Thanks.

[Landlord101]

I have received the new voltage regulator.  I note that the resistance reading between the field terminal and ground is about 10 ohms.  On the old regulator it is grounded.  So that would explain the full-time charging behavior as far as I can tell.

[Landlord101]

Question regarding polarizing the generator.  Presumably this does not need to be re-done with a new regulator installed.  It is not entirely clear to me what exactly is getting polarized - the generator windings or something in the regulator.

Also, the Delco-Remy service bulletin indicates polarization of the generator is done by momentarily connecting the "Gen" and "Bat" terminals of the regulator.  How is this different from just hitting the starter switch?

[Landlord101]

Well, the charging system is working normally now with the new voltage regulator.

Moral of the story:  disconnect your battery before charging it with an external battery charger, cause you can risk toasting the regulator otherwise.