CV16S alternator test

[bertsmobile1]

When it is nice & dark go pull one battery lead off.
If you get a spark then there is a load on the battery which is flattening the battery.
Most of the modern rectifier / regulators are always on so will put a tiny load.
If the beck feed diode has gone then overnight the alternator tries to be an electric motor ( electrically they are one & the same ) which will draw down the battery .
I leave mower out overnight , hood up
No dew on the blower husing or hosing warmer than the rest of the mower indicates rectifier failure.

 

[tom3]

Take a cable off the battery, hook it in series with a small 12v light bulb, look for any glow. Should be no drain on it. Does your multimeter have an amp/milliamp setting? Might check with that if so.

 

[Hammermechanicman]

Parasitic draw. Charge the battery. Set meter to AMPS and connect the meter leads between the + batt terminal and the batt cable. All current will flow through the meter. Do NOT turn the key on or try to start the mower. Will blow meter fuse.
If there is a parasitic draw it will show on the meter. Disconnect the voltage regulator and see if the meter goes to zero, if so check the diode or suspect the regulator. Is there is still current flow after disconnecting the VR then something wired wrong or shorted.

 

[PTmowerMech]

When it is nice & dark go pull one battery lead off.
If you get a spark then there is a load on the battery which is flattening the battery.
Most of the modern rectifier / regulators are always on so will put a tiny load.
If the beck feed diode has gone then overnight the alternator tries to be an electric motor ( electrically they are one & the same ) which will draw down the battery .
I leave mower out overnight , hood up
No dew on the blower husing or hosing warmer than the rest of the mower indicates rectifier failure.

This mower doesn't have a rectifier or regulator.

 

[Hammermechanicman]

One of those goofey 3 amp unregulated charging systems?

 

[StarTech]

This mower doesn't have a rectifier or regulator.

Wait one dang blame minute here. It does have a rectifier, that what the diode is. Diode and rectifier are interchangeable terms. Now there are different types for special purpose like a zener diode which are voltage regulators. It is right there that we been talking about checking in the image posted. It is high temperature SOD-57 case Silicon 3 amp diode. Can be replaced with a 1N5408-G diode 1000V 3 amp axial lead case 267-05 style 1.

One of those goofey 3 amp unregulated charging systems?

And yes it a 3-5 amp unregulated system. Luckily here that it don't also have stator brake winding.

Take a cable off the battery, hook it in series with a small 12v light bulb, look for any glow. Should be no drain on it. Does your multimeter have an amp/milliamp setting? Might check with that if so.

Most meters will only go to 10 amps and that is an unfused test mode so if there more 10 amps draw you will fry your meter. Uae this mode only if you know for sure the circuit is drawing less than 10 amps. Use 40/400 amp clamp type amp meter or similar meter adapter. And yes that diode can be leaky.

 

[PTmowerMech]

I put a different battery on it, mowed for about 10 minutes. The battery, with engine off (7:00pm) is at 12.90v). If it's dead in the morning, I'll have to start all over.

Now, at 9:30am, the next morning, I'm at 12.76. A .14 drop, just from sitting. That's a lot better than it was. Yesterday it would've dropped that much in an 1/2 hour. All I really did, yesterday, besides checking current, was swapped a ground wire from the top to the bottom of another one.

One thing I did before I finished for the day yesterday, was check the continuity from the +POS side of the battery to the engine on this one, and a few others. All of them were 042 to 045. I don't have a clue as to why. But they all read that.

 

[PTmowerMech]

When it is nice & dark go pull one battery lead off.
If you get a spark then there is a load on the battery which is flattening the battery.
Most of the modern rectifier / regulators are always on so will put a tiny load.
If the beck feed diode has gone then overnight the alternator tries to be an electric motor ( electrically they are one & the same ) which will draw down the battery .
I leave mower out overnight , hood up
No dew on the blower husing or hosing warmer than the rest of the mower indicates rectifier failure.

I just tried this and didn't see any kind of a spark. I didn't read this til this morning, so I didn't try the dew trick. The batter did drop about .14 in 14 hours. Which isn't much. But being left for a week, I'm sure it'll be a problem.

 

[PTmowerMech]

@2:30 this afternoon, it's still at 12:76.

All I did was unwrap, check and rewrap the diode. Remove a ground bolt, putting the bottom wire on top and re-tightened it.