@Garym, your dashboard has to "know" somehow, to switch its charging light on.
So, as already stated all around, a short, a loose cable, simply a malefunction appears.
Having your multimeter, next steps to check would be
-battery voltage (motor off)
WRITE EVERY STEP DOWN
-battery voltage during starting
-delivered voltage from generator to battery
-lights on during running, voltage?
It has to be found out where the "leak" is located at.