Good math Herman ;-) I got my 7710 from CW while passing through NH last May and as I posted in another forum the battery charging system went south on me on the way back from a 48 day west coast trip. Bottom line, as others have said, the RVND 7710 most probably has at leas some failed units or units which haven't been used long and hard enough to collapse like mine did. My faith in RM can only be restored if they treat me right with a good trade in program to a 7720 which has some nice features e.g. WIFI for instant weather updates and hopefully fixes any know 7710 problems right out of the gate. I hope they do well by their original purchasers on the cost issue as the unit is definetely a great help while driving an RV.
Cesar Cardenas F127604
Four Winds 23S until I got to Tucson and fell under the spell of a 38' Thor Magellan at Lazydays Tucson