Why don't you install a circuit to from your MH to keep your toad's battery charged? Hopefully your 7-pin receptacle on your MH has 12V DC power at pin 4. It's easy to check with a multimeter and, ideally, should only be hot when your motor is running. If not, it's a relatively easy DIY project:
https://www.northtexastrailers.com/c...iring-diagrams
Although some just wire direct to the Toad battery, this can be problematical, especially without fuse and diode protection. There are a number of options available that protect your battery and manage the connection. Rather than recommend any specific one, here are some options and links to relevant RV forum postings:
https://www.google.com/search?q=toad...client=gws-wiz