Having some weird stuff going on with battery and can't figure it out. Could use some help, if you have any ideas.

Here's the whole story. A little long, but I don't want to eliminate any detail that might give someone a clue as to what might be wrong.

---

2008 FXDF. 4000 miles. Bought it in January. Had it checked out; no issues. 15mph lowside slide in traffic circle (thanks, minivan) in February. Checked again, no issues. All ran fine. No issues. Replaced the tank, fender, etc. from the accident.

May - Accidently left the lights on. Original battery died in about 2 hrs. Jump started off my car. Ran fine. June - left lights on (again) and was out of town for a week. Battery seriously dead. Wouldn't jump start. Replaced battery. Started immediately.

July - Started slow one day, like battery was weak. Rode for an hour or so. Stopped and battery was too weak to start the bike. Jumped it off a Goldwing. Got it home. Wouldn't start; wouldn't jump. Starter clicked like a machine gun but would turn over at all. Put a new battery in it. Started right up.

Before and after battery #2, I checked everything I could. Ground wires are clean and no shorts. Starter relay is fine. Started motor seems fine as the bike starts with a fresh battery. When running, I am getting 14.16 volts across the battery posts with no voltage drop between the regulator output and battery. Lights don't dim when I rev the engine. So it seems that the alternator and voltage regulator are OK.

Have been checking the battery voltage periodically and drop when I start it. When it was new and fully charged, the battery was between 12.96 and 13.1 volts after sitting on the charger overnight and resting a while. Still getting those numbers. When it was new, voltage drop was to about 10.5 when I hit the starter button.

I rode it a bit and didn't put it on the charger for a week or so.

Now, after about 500 miles, its acting up again. It sat on the charger for overnight. Read 13.1 volts on the battery after I took it off the charger. Started, but seemed a little weak. Drove it about 2 miles and stopped. Started but very weak, so I went home.

Hooked it up to the voltage regulator. 14.1 volts while running. Stopped it and started it 3 times. The voltage drop was to about 8.8 when I engaged the starter! It had been sitting on the charger all night.

Rode it for a bit. 14.1 across the posts when I got home. Set it on the charger and the charger says its not fully charged. Let it sit a bit and started it up ... almost didn't start (chugged slowly before it started) and the volt meter went down to about 6 volts when the starter was engaged.

So, I can't find any wiring problems or shorts. No voltage drop issues in the system. The alternator and voltage regulator seem to be working fine. Brand new battery. Runs well after it starts. No problems with the lights dimming or changes in the voltage readings between hot and cold. Yet, the battery feels like it is weak. It certainly doesn't start as strong/quick as it did when the battery was new a month ago (about 700 miles).

Worried I am going to chew through battery #3 at any moment. At $100 per pop, I can't afford to keep this up any longer. Both new batteries have been CycleTron II from Interstate and were filled and fully charged just before install.

Any ideas at all?

 

The battery seems to be ok....so you must have a charging system problem. Maybe you have something discharging it heavily. You could try to put an amp meter on it to see what the current is doing and which direction it's going. Hope this helps a bit.

 

I have same problem. I put a amp meter and found out i have 4.63 amp draw someplace. I pulled fuses and found the battery fuse to stop the draw just have to track it down now. If i find it ill let you know. Im a tard was checking the amps wrong.

 

I figured out my problem last night. My bike was doing the same thing as yours and driving me nuts. I figured since the battery was getting a charge that the Voltage Regulator was good. However its not. When i did the test with a test light the first time i did something wrong and it showed good. I double checked it last night and it showed to be bad. Dont asume like me that your regulator is good becouse your bike seems to be charging the battery. Double check the Voltage Regulator if you havent allready i bet thats where your problem is.

 

I saw your earlier message and checked the amp draw on the bike with everything powered down. It was 0.015 mA.

Kept it on the battery tender and after riding it once, it started. Runs fine. Went to start again and the battery sounded really weak ... and sounds weaker every time I go through the cycle of tender-charging and starting. Voltage dropped to 5.5 when I cranked it ... I'm afraid I'm about to destroy another $100 battery.

I appreciate the tip and glad you found your issue. I'm pretty sure mine is not the AC as it runs fine. Didn't think it was the regulator as I'm getting charging voltage and headlight brightness doesn't vary. Could well be wrong.

I don't know the problem and don't have the tools to load test and look at current when the bike is running and starting, so I punted and took it to the shop.

I hope its something stupid and cheap!

 

if the diodes are bad it wont charge properly , will actually drain the battery, have the charging system checked.

 

Thanks, SIDECAR BOB. I took it to the shop yesterday. First time I'm using these guys, so we'll see how they do.

 

Voudoujoe,

After you hear from your shop could you please let me know what they say? I thought i had mine figured out however that wasnt the entire problem. Im still thinking battery since Stator, and Reg are new, and i have no shorts or load draws.

Good Luck and Thanks

 

You probably have a bad stator or voltage regulator.

 

Sure. I put it up here as soon as a get over cussing about the the bill.