You would need to connect the two 12 volt batteries in series. That will give you 24 volts and the amps of one of the batteries. Voltage doubles and amps stay the same.
Possibly but you will have twice the amperage for sure. So the 2 batteries will run the trolling motor far longer. My guess is yes, they will last longer than just one battery. That is an educated guess.
To get 24v from two 12v batteries you just link between ones positive and the others negative then connect your motor to the spare terminals, but your 12v charging system will not charge them (and any 12v equipment connected to them will burn out!) without removing the link.
If it were me, I would purchase a 55 lb thrust motor and it would be a Motorguide. A 55 lb thrust motor will be a 12 volt system. Beyond 55 lb you'd need to move to a 24 volt system that would require two 12 volt batteries for the trolling motor. A 24 volt motor would offer around 80 to 90 lbs of thrust. Unless you're going to use your boat in heavy currents or strong winds, I'd opt for a 55 lb motor.
in series
step up trasnsformer <<>> As suggested above transformers do not work on DC installations. You will need to use two 12 VDC batteries in series with each other to obtain the 24 VDC needed to operate the motor. Connect a jumper between the two batteries with a wire the same size as the wire coming from the motor. The jumper will go from the negative of one battery to the positive of the second battery. The two remaining posts will connect to the motor and have a potential of 24 VDC.
You must hook them up in series. You will need four 12 volt batteries to do this.
batteries are only used for DC CIRCUTS. if the motor is a DC MOTOR you can.
Separate the 2 12 volt batteries and charge them individually.
How to hook up 6 8v batteries in searise <><><> Batteries connected in series have the negative (-) of one connected to the positive (+) of the next, until all 6 batteries are connected.
You can hook up an infinitive number of 12 volt batteries in a parallel circuit and still have 12 volts.
No Yes. hook two in series, two in parallel.
NO. Absolutely not, you must hook them in parallel. Two 12 volt batteries hooked in series will give you 24 volts with the same A/H of one of the batteries. Hook them in parallel and you will still have 12 volts and double the A/H of one of the batteries.