I have a 06 Ultra Classic. The voltage gage drops 14VDC to 10 VDC and the battery and check engine light comes on. This may last for several miles and then it returns to 14 VDC and the check engine and battery lights go off. This will happen several times in a 50 mile distance. What would cause this and what would be some things I could check.

 

It sounds as if you might have an accessory which is drawing too much power, then a breaker blows and the volts come up...then the breaker cools and resets... and the voltage reads low again.
(do you have anything added or changed to the stock wiring?)

but first you have to check that you are getting proper voltage at the battery with a "real" meter ( because the one in the dash is not the best and if you had corrosion on the wires to the gauge, it would maybe read wacky

so voltmeter on battery, motor off it should read 12 volt-ish, start bike, rev up over 3000 rpm and you should see about 14.5 volts.

if you have readings that differ greatly from that you have a charging system concern.

check those first.

it may also be a good idea to pull the battery, charge overnight on a "real" charger if you have one ( not a tender or trickle charger)- take to autozone and load test...

possible the battery is loosing a cell, which would put a great strain on the charging system- causing further damage.

couple of checks, let us know how you do.

mike

 

First thing I would do is make sure your battery terminals are tight. My bet is something is loose

 

My bike did the exact same thing when the stator was on its way out, after awhile it stopped charging.

 

All good recommendations above. Check battery terminals and wires for corrosion, and be sure to check your regulator grounding too.

-Dusty