3 Bank Charger for 2 batts

Picked up a good used 20amp Cabelas Pro-Series 3 bank charger awhile back. But I'm only running a 12v bow mount, so I only have 2 batteries in my boat.

I will likely switch to a 24v motor in the very near future, so picking up the 3-bank charger made sense to me.

However, how are guys hooking up a 3-bank charger to only 2 batteries? Do you double up the leads on the bigger trolling motor battery and henceforth double the charging AMPs? I've read in a few places that guys are doing this, but that's just forum talk from guys I have know idea who they are. I'd like to see if anyone here has any experience with that...that I would trust. Don't want to fry my charger or burn the garage down...

Or do you isolate the leads for the 3rd bank and run the charger with the warning light lit on the 3rd bank? This is the way I hooked it up for now. The "charging" light is on. There is a "check bank" light illuminated for the leads I didn't use. And the system status "OK" light isn't on, so I'm questioning if its even charging.

Thoughts or input?

 

Unfortunately, I think it'll vary depending on the charger. The noco that I have is a smart charger which checks for some voltage before it does anything. It will also prevent any sparking if you accidently connected it incorrectly or touched the leads. When nothing is detected on mine it shows orange, when it's charging its red and when done it's green. I would just leave the extra bank cabling unhooked but validate that it's working with a multimeter or something after and not try doubling it up. The risk is not worth the outcome of a slightly faster recovery time in my opinion but curious what the other folks have to say. You might want to occasionally change the bank that's being used so you don't wear one out faster but pretty much everyone I know who's had a bank issue was the same problem -- one bank stopped working.

I have 3 batteries in my boat and only opted for a 2 bank charger since I have a 60hp Yamaha which does a good job of keeping my battery topped up after I drive back to the boat launch. I've thrown the smaller charger on it a few times and its at or near full. All three batteries are 2 years old now.

 

Did a bit of digging. ProMariner builds the on board chargers for Cabela's.

This was on their website regarding un-used DC leads from the charger:

Q: What do I do if I have an unused set of DC wires from the charger?

A: Double up the charger output Bank 1 and Bank 2 wires on your “most used” battery. This would be the “House” or “Trolling Motor” battery. That way they can all sense a battery voltage and the unit will charge properly.

Ran to the garage and did a quick switch. All lights green and I have 13-14v running to each battery. Viola...problem solved!