The best add on you can do for dingy towing, I have had a charge wire since 2002 and have never had a dead battery on the CRV in over 40,000 miles and the Unified brake system I have does use the toad battery to run a vacumne pump on the toad. When you run the wire, install a 20 amp circuit breaker near each battery to protect from any possible short in the charge wire. just remember to disconnect the seven way if you park overnight without unhooking the dingy or you could run down the dingy battery