Trickle chargers are pretty old technonogy. They will still cook your batteries because even though it is a low current, it's still steady whether the battery needs it or not. You really need a Smart battery Charger with multi-stage charging and a float mode. The newer one also check the state of the battery and do an equalization at specific intervals.
2015 Seaark 1872 MV CC Etec-90
Helix 12 CHIRP SI, HB 1199, MinnKota Riptide ST80/i-pilot Link, Bob's Hydraulic
Bitter Gun Owner