2012 Ultra limited her. Bike runs great and all is well. Seems like when bike is running on the express way the battery gauge voltage is at around 13.7 V or so. I just noticed today that when the bike is at a light and idling I read about 12 V. I do not remember that? IS that ok or should the voltage reamin close to 13.7 V? Thanks

 

With you ignition on and before you start your engine you are actually reading your battery voltage. After you start your engine the alternator begins making power and providing that to charge your battery and power your system. The voltage the alternator makes is dependent on RPM so the faster your engine is turning the alternator the higher the voltage (to 13.8 or so). The voltage regulator keeps the voltages in check by clipping off anything higher than that 13.8 V but there is no bottom limit really.

 

I wouldn't count on the Harley gauge to be accurate. Having said that a healthy fully charged battery should read about 13.2 volts, 2.2 volts per cell. The voltmeter on my bike reads a touch over 14 volts running down the road. It only drops slightly at idle. If you gauge is right that means the battery is discharging at idle. Just grab a volt/ohm meter and go right to the battery terminals and check. Check it at idle and about 2,000 rpm. The charging system has to put out more than battery voltage at idle or or you'd be running off the battery and discharging it.

 

Ive seen a few threads on this subject and this is common i wouldnt worry about it unless you start havin trouble*with it startin. Mine usually reads in the 14's maybe even close to 15 all the time rather im at idle or cruisin down the road. Maybe im just lucky or give it a few more years and mine will act in the same manner.

 

If you are concerned, or just want confirmation, use a multimeter, don't rely on the voltmeter on your bike. That is fine for indicating a change that you should know about, when you should then take a closer look.

As a trainee engineer I was taught that when a warning light comes on, the only thing we can be sure of is that the bulb works! Next step is to check what the light is telling us. Same applies to a voltmeter - if it changes, check with a proper one!

 

If you are unsure then I would definitely check the voltage right at the battery with a meter. Dash gauges are notorious for being off. A difference of 1 volt can mean you are more like 13 v at idle and 14 running down the road (and that is where it should be)

A healthy fully charged battery should be at 12.6-12.8 with the bike off sitting at rest. This is with the key off.

 

don't trust the gauge if you are worried about it check it with a trusted meter

 

Mine will drop some at stop lights if my hand is on the brake, all lights are on, heated grips on 6, turn signal flashing, iphone charging, gps on and tunes playing. Drops to about 13. Release the brake and it climbs back up. My point is, what is your draw vs capability of charging system. My 99 FLHT Standard would drop way down at idle... The standard back then had a weaker stator and P&A catalog back then had an upgrade that said "upgrade to same stator that is stock on an ultra classic to allow the addition of lights and accessories "

 

With a known good meter, my good battery at rest is 12.4 volts.
When I start up, charging system goes to 14.4 volts.
After running a short while, system fully recharged, system goes to around 12.8 volts.
YMMV.
These same numbers are duplicated with the HD Smart Charger BTW. What ever the battery voltage when plugged in and connected to battery, it eases up to around 14.4 volts (Yellow light), then eases down to 12.4 - 12.8 volts to maintain (Green blinking light as it is dropping, then steady Green light at 12.4 - 12.8 volts).
This pattern repeats itself over and over. It is a good pattern that of course can vary with load, yet prevents overcharging via the "maintain" cycle.
This is on my '11 RKC, YMMV.