I was told to move this post to the evo section. Here is the link.

https://www.hdforums.com/forum/elect...ical-help.html

 

Could it be that the batteries your using can't handle the vibes, if its charging O.K, and the grounds and cables are good, don't know what else it could be. I use an AGM Harley battery.

 

I'll repost your post here so those here can see it without needing to go to the other thread to find what this one is all about:


Rebuilt bike ... Are you certain all the ground straps from the motor to the frame are in place?

I would have pointed to the regulator as over charging and destroying the batteries but you have the correct voltage, and even replaced it so there shouldn't be any issue. 14 volts is real good, could you have A/C coming from the regulator(s)?

Did you recharge those 3 batteries to see if they are taking a charge and holding for a period, like overnight?

Do you have a lot of aftermarket lights like additional front spots, or extra brake lights?

Do you have a sticking brake light switch?

 

Should be charging at around 14.6 volts at the battery. Hopefully Doc Hess will be along soon. He has posted excellent advice on the charging circuit and a variety of checks we can make.

 

+1 on that! I've used a few different types of after market batteries with most failing early. I've been using HD batteries now for over 15 years with no problems.
Just my .02 cents...
jim

 

Dr.Hess' How To Diagnose Your Charging System
Buy about a $10-20 digital multi meter. Fully charge the battery (overnight on a 1 amp charger).

Scale on DC Volts, around 20V max voltage scale. Nominal readings are given in brackets. Check voltage across battery terminals (12.8). Turn bike on. Check voltage (less than previous, ~12.0+, depending on headlight, accessories). Start bike and let idle. Check voltage (could be 12.0 to 15). Rev to about 2500. Check voltage (should be more than observed with bike on but motor not running, and more than with bike off. Ideally between 13 and 15.) Turn high beam on. Should be about the same, give or take a little. If the voltage is over 15 or 15.5-ish with a headlight on, I'd consider replacing the regulator and/or checking all grounds (battery to frame, regulator to frame in particular).
If you pass the above tests, your system is most likely fine, including the regulator and stator. If you don't pass, then:
Bike off. Meter set on Ohms, medium-ish scale, like 20K or 200K Ohms max scale. Pull stator plug. Ground the meter black lead to a good chassis ground, like a bolt or even the battery negative. With the red lead, touch a different part of the bike, like the engine case at an unpainted part or another bolt. Meter should read low ohms, like 0. With the red lead, touch each contact on the motor side (stator) of the plug (the part stuck in the case). Depending on if your case has a male or female plug, if you can't see the metal part/pin of the plug, you can put a paper clip in the hole and touch the paperclip with your meter red. Meter reading should be infinity on all pins. If it isn't, your stator is shorted to the case, replace.
The following is for single phase systems. I don't have a multi-phase and haven't had to diagnose anyone elses, so I haven't dug into those systems.
Set meter to lowest ohm scale, like 200, typicaly. Check resistance between the two stator plug pins. Should be fairly low, like a few ohms. The spec is in your shop manual. If it is infinity, stator is blown open. If it is 0, stator is shorted to itself.
Set meter to AC Volts, 100V scale. Attach each meter lead to a stator pin. You may need to rig up some type of temporary plug. It is important that nothing can short to ground or to each other accidentally, or you will blow the stator if it wasn't blown before. An old plug off of your last regulator is a good way to do it, but, get creative and be careful. I can do it holidng the leads on the pins once the bike is running, but I don't like to. Start bike. Voltage should vary with engine speed. Specs are in your shop manual, but 35V at a couple thousand RPM is probably about right.
If you passed that stator test and failed the first test, your regulator is shot. If you failed any part of the stator test, replace both regulator and stator.

 

If all the above checks out then what gauge wire do you have from the regulator to the battery?? Is the terminal crimped or soldered. Just because the terminl is crimped on tight doesn't mean it is effecentily transfering current. Next what brand of battery do you have and what is the rating on it?? Lastily where is the battery mounted. Is it in the oil tank where it gets lots of heat? If so we've seen this heat kill "cheaper" batteries. Hope this helps.
John

 

I've done the full test and everything checks out fine. The regulator wire looks good size, it came on the regulator. The connector is crimped on though, I will check it soon. The battery is in a typical spot but the exhaust wraps around the box and exist under the seat. It does get hot but I can still touch the box with my hand. The battery is not HD but it is a AGM X2. According to batteries plus, it is the best you can buy. No problem with orientation vibration or whatever.
This is a custom bike so I've put my own ground straps where I think is right. I've got one big wire from the battery to the starter bolt. The ignition and lighting ECU are directly to the battery. And the regulator has a ground to frame. Headlight and turn signals are grounded to frame. I've wondered if I need aground strap from the engine to the frame but I've got good continuity. That might not be enough.

 

Ignition and lighting ECU directly to the battery... Problem there. Shouldn't stop you after it has been running, but that could drain the battery while it sits.

These dead batteries, did you charge them up overnight on a 1 amp charger and then test them before you traded them in?

 

It's only grounded directly to the battery, not power.
I put the bike on my battery tender once in a while. After they died, I tried putting it on a tender and it wouldn't take a charge. The battery place said that it was fully charged but that the cold cranking amps had been reduced to 2CCA. It's rated at 220CCA.