I have an 05 Ultra and noticed the Volt gauge was down to aroud 10 - it usually reads about 14. I checked all the battery connections, bought a new pigtail for the battery tender since I've had it for about 15 years, used on prior bike. Still have the problem.

I searched on this forum and found some useful info how to check the voltage regulator ( Disconnect the stator from the voltage regulator and start your bike. Take volt meter and check your voltage from the stator connector at 2500 RPMs. It should read around 42 volts AC. If your getting 42 volts it's not your stator. Reconnect your stator to the voltage regulator and check the voltage at the battery with the bike still running. At 2500 RPMs it should read between 14 to 16 volts DC. If your getting less than 12 volts it is the voltage regulator.) and this is the link ==> https://www.hdforums.com/forum/elect...hlight=battery

When I disconnect the stator from the voltage regulator, the bike won't start at all - hardly any cranking power (the battery is fully charged showing 12.9 V at the battery).

I reconnected the VR, started the bike and disconnected the stator from the VR and the bike immediately stalls?

Is it there something I'm doing wrong?

Any help is greatly appreciated.

Thanks,
Bill

 

Sounds like your battery is toast............ Borrow one & run the tests again.

 

I don't have anyone that I can borrow a battery from. Any other suggestions?

 

Buy a new battery. Rerun the tests if you wish.

 

Is this your original battery in your '05?

If so do you keep it on a tender?

And do you keep it parked for long periods of time with alarm on and short run times when you do run it?

 

Yes, this is the original battery. It's had a battery tender on it since the day I brought it home. I usually ride most weekends, weather permitting, year-round. This winter hasn't been good for riding for me. When I do go out, I usually ride for 1-3 hours, mostly cruising at highway speeds.

 

your bike should run with the regulator unhooked ? You never stated if you checked the voltage at the battery when the bike is running with the regulator hooked up ? Or was that 12.9 with the bike running and the engine rpm up ? If so id look at the battery also . But if the 12.9 was with the engine off then with every thing hooked up and running you might as well look for the 13 to 15 volts from the regulator.. The other option is to tap into the stator wires to the regulator and check it..

 

Sounds like the battery is at the end of its life cycle.

Also you don't want to connect or disconnect the VR from either the input or output when the engine is running. Will cause surge to VR and possibly weaken or destroy it. My instructions were to have engine off at all times when connecting or disconnecting VR.

Additionally 3 phase 45 plus Volts AC from the stator can give you one good jolt if your not careful. And it has capability to draw a nice arc and can weld leads or wires to the point of melting as well.

Observe EXTREME Caution on this ckt especially!!

 

Bring your battery to a dealer. They will put it on a charger overnight and then test it the next day with the Midtronics Battery Tester. The tester will spit out a ticket whether your battery is toast or not.

 

Check battery voltage while trying to start. You will need slightly more than 11 volts to start the bike. If it drops below 9 volts volts than I would guess your battery has a dead cell. A battery with a dead cell can still show good voltage untill a load is placed on it. Your battery needs to be 75% charged (tested with hydrometer). Having said all that, I agree with the others, you probably have a bad battery. Have the battery completely charged and load tested just to make sure.

Mark