Maintaining toad battery

[MrE]

Any recommendations on maintaining a charge on the toad battery? My toad requires that the ignition is turned to position two to keep the transfer case in neutral, creating a drain on the toad battery. From what I've been able to find in my research is that the toad battery will be dead in 10 to 12 hours. 

I would like a coach side solution that will insure that it will never fully drain the coach batteries.

[Fulltiming]

I have had good luck with the Toad Charge http://www.lslproducts.net/ToadChargePage.html. It does require another power cord (included) between your coach and the car but the quick connects work well and I just attached it to my existing wiring bundle with zip ties.