To get back to your original question...all motorhomes are supplied with very large output Alts. If you can monitor the output at the batteries or at the dashboard 12VDC socket with any digital volt meter you will typicaly see a partially discharged battery being initially recharged at about 14.6 vdc and as it charges, the current demand will decrease & also the alts output voltage down to about 13.1 to 13.6 vdc. If you have a plug in type meter that can stay in the dash cigarette lighter 12v plug you'll see that it will fluctuate from 12.5 to about 13.3 vdc. about every 20 seconds as you drive.