I have a two bank charger but the one that is connected to the cranking battery isn't charging for some reason. I have an outside charger that i can hook up to it. my question is do i need to disconnect the cables that are already connected to that battery before hooking up the outside charger?

Coach.. if there is no voltage coming from the two bank charger, it won't hurt anything to connect the outside charger to the battery. There is usually an inline fuse with each output of an inboard charger, did you check that?

Good luck
BD

No I haven't checked it. thanks. I am just concerned about all my other electronics that is connected to the cranking battery. Outside charger wont affect any of that?

A charger is a charger as far as the stuff is concerned unless you're charging AGM battery. They have special needs.

After further inspection the 2 banks are connected to the trolling motor batteries only. I feel stupid for assuming one was connected to the cranking battery. This explains why my power poles drained my battery with the charger connected. One of the lights of the onboard charger still isn't coming on. I have checked the fuses and connections and are all good. It is under warranty. Looks like NOCO will be sending me a new Gen2!

In time like this a voltmeter is your friend.

I learned the hard way to use a voltmeter anytime it comes to anything battery related. I wasted a ton of time chasing wires and playing with chargers before realizing it was something way more simple.

if you need a single bank charger ? I have a year old minkota that i would like to sell, changed my battery out and needed different kind of charger. It works perfect .