To all,
I have a 2008 Ultra Glide Classic (FLHTCU). I recently put in a new battery. The battery reads 12.8VDC with the bike off. The Voltage Guage reads around 10-11 Volts with the bike off. Obviously there is a discrepancy. While running, the Volt Guage reads above 14VDC. Is there a way to calibrate or adjust the stock Volt Guage to read the same or is there a draw between the battery and the guage that is causing the guage to read lower?
Thanks for any help,
Chris

 

Well the good news is 12.8v is a charged battery. With bike running, 14.2v or so around idle is properly functioning charging system. The factory gauges are inaccurate so I wouldn’t worry too much unless the needle starts fluctuating or it drops below 14v at idle then you might have a different issue. How long did your last battery last?

 

"with the bike off"

The only way to get the meter to show voltage is to turn it on, and unless you pulled all the fuses anything that powers up with the bike without the RUN switch on is going to draw current..... HEADLIGHTS perhaps?

Both my bikes show under 11 volts when the bike is powered up without the engine running.

14.2 volts running is normal, as long as you have enough voltage to crank the bike and keep the ECM on ( low voltage and the ECM will not power up as a safety precaution to keep the module from self destructing) it doesn't matter what the meter says.... it is either charging or it is not, very rarely will you see one over charge

 

H-D voltage gauges are as accurate (or worse) than the ambient temperature gauges.

There may be a way to recalibrate it but I certainly am not qualified to comment on the method and question whether it would be worth the time, and expense.

If you truly want an accurate voltage indication, replace the gauge with a quality one of the same size. In fact there are some very inexpensive charging port plus (USB) that also include a digital voltage indication. I don't know how long they will last but for what I paid, you could purchase a handful of them. If you chose to remove the stock unit, a black plate could be fashioned to accommodate the large hole and the smaller replacement unit.

Alternatively, you could have an accurate handheld gauge attached and make a cheat sheet translating what the H-D gauge indicates into accurate voltage values. That's actually what is done with the whiskey compass on boats and aircraft.

 

Between the smaller gauge wiring to the gauge and its ground wire, and the fact that the lights will be on when you have the ignition turned on and the motor not running, the lower voltage at the gauge sounds about correct to start with.

 

Consider your Harley gauges to be 'warning lights'.....only pay attention to them if they are registering zero. The same goes for the oil pressure gauge. Im am a 'gauge watcher'....all my hotrods had nice dash clusters and I could tell the minute something was a few PSI or degrees off. Harley gauges are more of a decoration. I only glance at them once in a while to see that the systems are just working and I dont pay much attention to what they read, as long as they are in the 'general area' of what I know to be the 'average' running range. Unless you are having battery or other electrical issues......just ride and ignore it.

 

In the back of the voltage meter gauge, there is a small screw, connect a quality digital volt ohm meter (VOM) to your battery, start the motorcycle, and use the screw to calibrate the voltage meter to the VOM. It is probably only off by .1 to .3 volts anyhow if you are reading 14.1 volts while running.

 

i was able to calibrate my volt meter on my 2001 electra glide, but you need to take the volt meter out, as the calibration hole was on the left threaded side of the meter, not in the back as usual. I used a known voltage source tested it with a digital meter and hooked it up to the meter and made the adjustment. A little more work, but saved the price of a new meter. Best wishes Don

 

You typed "The battery reads 12.8VDC with the bike off." Measured with what? How did you measure that voltage?
Then you typed "The Voltage Guage reads around 10-11 Volts with the bike off."...taking a guess that you mean the factory voltage meter on the bike but if the bike is OFF then how is the factory voltage meter working?
Yes, there is a way on some bikes to calibrate or adjust the stock factory gauge as explained by another poster...but you would need to confirm operation of external meter for accuracy in order to address adjustment.

 

Just noticed this is about 2 years old.
Voltage is probably no longer a concern.