Call me paranoid, but I have my tenders on a power strip connected to a 7 day timer. kicks on Wed. night for a few hours, and Sunday afternoon for the same.
You won't get the full benefit of a tender that way. They don't just trickle charge. If left on, they go through a regular maintenance cycle as well, discharging and recharging. Intended to extend battery life by reducing the 'memory' effect.
I suppose there might even be a chance you turn off the supply at the point it completes the discharge phase! Unlikely though.
Since my last post in August, I too have changed to lithium. My battery tender died, and I had been traveling for work all of August. Man, that tender had been rock solid since like ‘0&.
Lithium batt has a bit more starting power