Batteries are new. I will continue to monitor to see if there is something going on with a unknown current draw. (several modifications have been made by previous owners - alarm/remote start/... - so it is difficult to know exactly what is going on)
The use of a separate battery charger would require the inverter and seem more complex than just using the Trik-L-Start. It appears to have all the smarts to effectively replace the charger with no user intervention and would be an excellent long term solution. Maybe I'm missing something.
Thanks to all for the discussion.