On checking with Roadmaster I received the following from Technical Support:
"As for your vehicle battery running dead. Does your Honda owners manual require you to remove any fuses? If so, then you may consider purchasing the Fusemaster part# 76511. This should help, with the battery draw. The Fusemaster takes the place of the fuse that needs to be removed. If you would like to see how it is installed, then simply go to YouTube and type in Fusemaster and you will see the Fusemaster installed in a Honda CR-V.
To diagnose if your charging feature is working for the Invisibrake, then simply, with the CR-V connected to the motorhome, disconnect the red wire & black wire from the battery of the CR-V and turn "ON" the headlights on the motorhome. You should have 12 volts & 2 Amps going to those wires. The Invisibrake is set up to maintain the battery not fully charge it. If your draw is greater than 12 votls & 2amps, then the charging system will not be able to keep up. Hope this helps, good luck and have a great day."
My CRV has the NAV system and the screen cannot be switched off except by pulling the fuse. The draw from the NAV display may be greater than can be replaced by the charge wire from the RV. Now looking for a Fusemaster.....Anyone have experience with those?