[Fulltiming]

I have used a Trik-L-Start for years with good results. It is similar to the Echo-Charge. It a few amps from the house batteries to charge the engine batteries. It will maintain your engine batteries at about 0.2 volts below your house batteries and shut down if the house batteries are not charging. Since I keep my coach plugged in all the time, the engine batteries stay charged also without ever having to use the battery merge switch.