battery overcharging

[topgun]

Is this model intended to always have headlights ON (no switch)? and if so isn't this part of the load that would control system voltage? Inop lights = more voltage than desired @ battery?
just throwing idea out...

 

[2ball]

Most 12v lead acid can tolerate up to 16 vdc but it the AC component that worries me here as it seems to extremely high. Should be under 16 vac if the diode is good. But as I said before I never fully tested the dual circuit voltages on a good one to know definitely the general range. But I will later but that don't help right

Is this model intended to always have headlights ON (no switch)? and if so isn't this part of the load that would control system voltage? Inop lights = more voltage than desired @ battery?
just throwing idea out...

I have a light switch, and my lights don’t work for whatever reason. Good thought though that the lights should be burning and using the av volts.

 

[bertsmobile1]

Quite right , got that backwards will go delete my incorrect post

Bert, An open diode will not pass anything (light switch off). Think of an open circuit as two pieces of wires not tied together electrically. Now if the diode was shorted it be as if the wires were tied together electrically (light switch on).

With diodes there one other possible failed and that is a leaky diodes. Think of it as a water faucet that does turn off completely and just drips out some electrical impulses.

Yes diodes are considered one way devices but do fail three ways. Dead short, completely open, or leaky. And in this case it sounds like it might a leaky diode. Just not sure as I never fully tested a working dual circuit for what should be being observed on a test meter. Briggs just never published what I think they should have. And I do need get a new test lead for my oscilloscope as a mouse chewed the old in two.

Reference info on half wave rectifier circuits.
https://www.electrical4u.com/half-wave-rectifiers/
Note the battery is considered a large capacitor then smooths out the waveform.

I don't know if you're still struggling with this or not but it sounds like you've determined you have an unregulated dual circuit system. If that is the case then it is working as designed and you're trying to fix something that isn't broken.

The only thing that will cause over charging in a charging system would be a faulty regulator which it sounds like your system doesn't have. There is nothing that can fail with the stator or diode or wiring in an unregulated dual circuit system that will cause over charging. Those types of failures would only cause under charging or no charging. The Briggs manual doesn't tell you what the voltage should be on the battery charge wire, they only refer to amps and they say it should be between 2 and 4 amps.

I know you're working on a Briggs but I'm going to talk Kohler for a minute as basic electrical theory doesn't care what brand it's on. It still works the same.

Kohler tests their 3 amp unregulated charging system by voltage. Briggs tests by amps. They both state a minimum number but Kohler goes by volts and Briggs goes by amps. Kohler says the minimum dc voltage output on their battery charging lead should be 20 vdc. By that test you're actually not putting out enough voltage. Since Briggs doesn't give a voltage measurement I can't say if your 15.9 is low so the best test would be an amperage test. They don't give a maximum voltage because higher voltage doesn't matter. When it's working properly Kohler's unregulated 3 amp system is normally around 30 vdc. If it's putting out less that 20 vdc you would typically have a bad stator winding or maybe lost a flywheel magnet. If it's putting out zero, that would mean an open diode, bad flywheel magnets or again, a bad stator winding.

Think about this. What creates the charge in a charging system? A stator, flywheel magnets and engine rpm. The stator only has so many windings, the flywheel only has so many magnets and the engine only has so many rpms. To increase the charge rate you'd have to add more stator windings or flywheel magnets or increase engine rpms.

Again, all of what I am saying is based on an unregulated system. If you find out yours does have a regulator, you have a bad regulator.

If he is getting AC to the battery rather than the pulsed DC then that will appear as an over voltage and in any case it will destroy the battery in no time flat and possibly cook the stator as when the negative pulse passes through the battery that is the same as hooking the battery up backwards

 

[2ball]

Quite right , got that backwards will go delete my incorrect post




If he is getting AC to the battery rather than the pulsed DC then that will appear as an over voltage and in any case it will destroy the battery in no time flat and possibly cook the stator as when the negative pulse passes through the battery that is the same as hooking the battery up backwards

I’m getting both ac and dc

 

[VegetiveSteam]

Unplug the stator and check for continuity at the diode in the charging lead at the stator. You may have to peel back some heat shrink to get to it. Put the red lead of your meter on one side of the diode and the black lead of your meter on the other side and check for continuity. Then reverse your leads and again check for continuity. You should only have continuity in one direction. If you have continuity both directions then the diode has failed in what I'll call a closed position. That's pretty rare but it does happen. They normally fail open but if that were the case you'd be getting zero voltage. If you have continuity in both directions you need to replace the diode if it's replaceable. If it's not replaceable it's time for a new stator. You could probably simply put a diode in that wire but there is no telling how long the original diode will stay in that closed position. It will more than likely open at some point in the future and give you a no charge situation.

 

[bertsmobile1]

Is this model intended to always have headlights ON (no switch)? and if so isn't this part of the load that would control system voltage? Inop lights = more voltage than desired @ battery?
just throwing idea out...

No
On a duel circuit stator the DC for battery & Ac for lights have no electrical connection.

 

[Forest#2]

Harbor Freight AC volts test:
Set your HF vom on AC volts and with the engine not running test the bat voltage and see what reading you get. The meter should read zero.

Some of them cheap vom testers will read AC volts when when testing a DC voltage and non-filtered DC voltage will cause them to not read accurately, like when the engine is running.

If the diode is shorted high battery amps would go through the stator windings and burn the diode open and/or smoke the stator windings if not fused. (the diode also blocks back feed of battery amps through the stator winding)
If a 20-30 amp fuse is in place the fuse should eventually open.

Safety Notice: I think maybe you mentioned in a previous post the you SMELLED battery acid. If so you need to be very cautious. When you smell a battery overcharging or discharging at a high rate it is Hydrogen gas, very explosive and the battery can explode and sulfric acid is a bad thing when it get's on skin and in the eyes. If you smell such (and it's not your own gas) move away and take precautions. If you ever have a battery explode close to your face you will not forget such. Very bad thing, can even loose vision.

Not likely you are getting AC stator voltage on the battery terminals.

You might think about testing battery charge amps instead of volts.

 

[2ball]

Harbor Freight AC volts test:
Set your HF vom on AC volts and with the engine not running test the bat voltage and see what reading you get. The meter should read zero.

Some of them cheap vom testers will read AC volts when when testing a DC voltage and non-filtered DC voltage will cause them to not read accurately, like when the engine is running.

If the diode is shorted high battery amps would go through the stator windings and burn the diode open and/or smoke the stator windings if not fused. (the diode also blocks back feed of battery amps through the stator winding)
If a 20-30 amp fuse is in place the fuse should eventually open.

Safety Notice: I think maybe you mentioned in a previous post the you SMELLED battery acid. If so you need to be very cautious. When you smell a battery overcharging or discharging at a high rate it is Hydrogen gas, very explosive and the battery can explode and sulfric acid is a bad thing when it get's on skin and in the eyes. If you smell such (and it's not your own gas) move away and take precautions. If you ever have a battery explode close to your face you will not forget such. Very bad thing, can even loose vision.

Not likely you are getting AC stator voltage on the battery terminals.

You might think about testing battery charge amps instead of volts.

I have replaced the battery. All of this trouble shooting has to do with getting my new battery last a few years.
Can I test charge amps with the Harbor Freight multimeter? When I look online they seem to have a different kind of tester, not a multimeter.
I did buy the PN 790292 to regulate the dc volts for the future. I hope to get it on and test it tomorrow.

 

[2ball]

alright, so I have added one of these and it kept the volts down in the 14.XX range.

I was trying to figure out how to test amps so I was goofing around with the settings and set my Multimeter like this. I put it on the battery with the mower running and there was a spark, a pop and smoke came out of the hole. The meter got real hot. I am guessing that's not the correct setting to test amps?

 

[bertsmobile1]

Well it is limited to what is written on the front of the meter.
There is a small resistor in the meter that is now toast .
The best way is with a 1 Ω power resistor and a multimeter or a clamp meter