[khgeisler]

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.

The link does not work for some reason. What is it? I have AGM house batteries and lead acid chassis batteries and would like to trickle charge the chassis batteries.  I turn the engine battery switch off, why leave it on, but will not leave the merge switch on for weeks on end, solenoids tend to go poof.  memories from my boating days.  Plus the solenoid just lets the charge flow all the time.  You could boil the led acid batteries.