I’m looking for a new 3 bank on board battery charger. Right now I have a 2 bank and a 1 bank charger. ( I know you are asking why I have 2 different chargers? Long story)  Anyway, I’m looking to replace the 2 for 1. I was wondering what you think is a good one to get? Thanks for your input and advice.

I have the Minn Kota MK330D. Although I have only had it about a month and a half it works great. I leave it plugged in at all times. Temperatures down to 6 degrees and it hasn't given me any problems.

 

https://minnkotamotors.johnsonoutdoors.com/battery-chargers/board-digital-chargers 

2 charges is not a big deal,  I have a 3 bank and a single bank. Both are Dual Pro professional series and have been worry free for 7 seasons. 

I'm using a Minn Kota 315 (5 amps per bank).  Had it for two years and it's serving me well.

I have a Guest on-board charger I am selling if you are interested. 3 bank (10A each) with no issues. Works just fine. I will sell for $100 shipped.

 

I've also got a Dual Pro 3 bank. Not cheap, but not something to try to go cheap on either imo.