Neighbor was cleaning out his garage and just asked me if I had any use for a new marine battery selector switch. 

 

Thinking about using this to add a battery selector to my trolling motor.  I have a 12v Minnkota 55lb motor and 2 x 12v batteries with a Minnkota 2 bank onboard charger.  The batteries are in a compartment under the rod storage so its a bit of a pain to get at and swap the battery when one gets tired.  Ive tried wiring both batteries in parallel, and even though they are similar capacity they never seem to get a full charge and take forever to charge like this so Ive kept the batteries separate. 

 

Thoughts on the attached wiring diagram - should work but I wonder about the common ground with charging.

 

 

 

 

48 minutes ago, Jethro313 said:

Ive tried wiring both batteries in parallel, and even though they are similar capacity they never seem to get a full charge and take forever to charge like this so Ive kept the batteries separate. 

That's a typical issue - to take advantage of parallel wiring, both batteries should be identical...even down to the same (or VERY close) purchase date.

 

I don't see an issue with wiring them up that way...just make sure the switch is set to OFF when charging.

I have one of those on my cruiser setup exactly like that albeit they are starting batteries.  Allows me to run one down with the stereo and flip it to 1 or 2 to start the engine to get home.

DC current has no common. Your AC charger should be a 3 prong grounded and GTG.

Thanks Guys - Looks like I have a project for after work today.  ?

 

The only thing that worries me about that diagram is the 'both' on the switch.  Does your switch have a 'both' setting and if so does it put them in parallel or series?  the last thing I'd want to do it mistakenly turn it to the wrong setting and send 24V through a 12V motor.  Just something to check on.

1 hour ago, casts_by_fly said:

The only thing that worries me about that diagram is the 'both' on the switch.  Does your switch have a 'both' setting and if so does it put them in parallel or series?  the last thing I'd want to do it mistakenly turn it to the wrong setting and send 24V through a 12V motor.  Just something to check on.

Since the negative doesn't go through the switch - it's a parallel connection.

4 minutes ago, MN Fisher said:

Since the negative doesn't go through the switch - it's a parallel connection.

 

good point.  I haven't done wiring diagrams for a LOOONG time and totally missed that.