typically, the generator will not charge your chassis battery and it sounds like you charged the house batteries.
(If you charged the chassis battery then stop reading here.)
However most rigs have a "boost" switch that uses your house battery to "boost" or jump the engine battery.
With your generator running and the boost switch held on, you will get the maximum boost.
If your rig does not have the boost switch, run a jumper cable from the positive post of your house battery to the positive post of your chassis battery.
Then start the generator and either charge the chassis battery or jump the chassis battery.
1995 CC Magna #5280
C8.3L 300hp Cummins, 31,000lbs