Installed a new 36v terrova this year, so I now have 3 deep cycles for the TM and one starting batt for the main engine and electronics.
I'm looking at on board charges for the first time.
I have a line on a couple of options.
A 3 bank minnkota mk345pc for the TM batts and just use a regular charger for the main.
Or install 2 minnkota 2 bank units to charge everything.
Cost would be about the same, will it cause any problems to run two 2 bank chargers?
With my set up?

I would do the three bank MinnKota charger for the TM batts and another small "smart charger" for the starting battery.

You might also look at Noco chargers. They make good stuff.