Hey guys.
I've got an electrical problem. I think I've narrowed it down, but I wanted to run it by you guys first before buying parts.

First Phase:

Bike ran out of electricity while I was riding it, got a battery voltage low indicator, and a check engine light. Made it home though, luckily I was close to home.

Charged the battery and then hooked up a voltmeter. On starting the battery sounded weak, and ran down to 7 volts. Once started the bike voltage rose up to 13.2 volts @ 2000 RPM. But it took several minutes to get there.
And the battery would only start the bike twice before it was flat again.

Replaced the battery with one from Advance Auto

Second Phase:
Went out riding, and I was getting occasional check engine light. Occasional as in after I would start the bike, I would get a light, then it would go off. Figured out how to read the code, and they are
P0562 Battery Voltage Low EFI
P0563 Battery Voltage High EFI

Not sure if these are leftover from before though.

So I measured my voltages again. On startup it now drops to 10 Volts, and then still rises up to 13.2 volts @ 2000 RPM. But it still took several minutes to get there, slowly rising from 12.4 to 13.2, but never rising higher than that.

Next. I took off the three prong plug that goes into the regulator rectifier. I am assuming this comes from the stator.
There is NO continuity from any of those three to ground. Which is good. There is very low resistance when measuring between the phases, but it's consistent between all three phases. Low as in 0.4 ohms (if my voltmeter reads correctly). I don't know if this is correct.

If the bike is running while I am measuring AC voltage at this plug, each one of them starts out in the 20 volt range, and increases with RPM to 55 volts @ 2-3000 RPM (guessing here as I couldn't read the tach at the same time as my gauge).
Between each of the three phases I get the same reading of AC voltage that increases with RPM.
Therefore I think my stator is good and healthy. Right?


I haven't ridden it yet since this test because I'm nervous about the high voltage error code. Which doesn't match what I am seeing from my measurements. If anything the voltage stays low.

Next thing to replace is the Regulator/Rectifier. But before I buy one of those, I wanted to make sure I'm going down the right path.

Bike is a 2009 Fat Bob. About 15,000 miles. High compression, so it takes alot of battery to start it.

 

You should be seeing higher voltage at the battery with everything connected, running at idle, 13.4 within a few seconds maybe, not minutes.

There are many threads here on how to test a stator, one is each phase to ground, but also between phases. Another is the voltage when running but that doesn't always account for current that it will take to actually get the battery charged.

Pull your derby cover off and smell the oil. If it smells burnt at all, you need to replace the stator.

Advice and a lesson that I learned the hard way, don't change the stator and not the voltage regulator or (I think) vice versa. Change them both at the same time especially if you do need to change the stator.

I am on my third set because of bad advice and worse warranties (HD OEM). I now have a CycleElectric Stator and Voltage Regulator and finally have no more issues with charging or burning up either one.

I don't normally endorse any vendor for fear that they'll embarrass me later, but must say that CE replaced my second stator FOC even though I still had an older HD regulator in the circuit. I was honest with them, they acknowledged that they hadn't warned me and replaced the stator. I bought one of their regulators as recommended and haven't had a problem since.

btw: My battery charges at 14.4, drops to 12 or so starting and comes right back up within about 30 seconds.

Here's something I put together after getting the new regulator. You need a tester with diode testing capabilities, reasonably cheap, ~$50.

Disconnect the VR from both ends and follow the chart below with Ohm meter getting the readings on the left and diode tester getting the reading son the right. Red and Black are the colors of the leads, ... need to be plugged into the meter properly ... sorry, had to say it because I make that mistake once in a while.

 

I had similar battery troubles - not exactly as you, but similar. My tests showed that the stator was fine. Because my battery was not very old, I figured that my voltage regulator was bad with some sort of intermittent condition which varied with heat or vibration; I never found out which.

I bought a new regulator. When I pulled the old one off for replacement, I could see a bulged heat-damaged spot on the back side. No issues since installing the new regulator. Battery survived, also.

I want to add that if you are considering total replacement, my indie-buddy swears by CycleElectric Stator and Voltage Regulator products.