I am replacing a very old Motorguide 12/24 volt 45lb thrust trolling motor with a new Minn Kota All Terrain 40lb thrust 12 volt.  I have 2 batteries on the boat for the trolling motor, old 12/24 unit.  How do I wire the new TM to both batteries so that when one 12 volt battery dies it automatically shifts power to the other 12 volt battery. Is this series or parallel and how do I do it?

The boat is 19 ft fiberglass.

Thanks in advance,

texasfishin

As far as 'automatically switching from one battery to the other when the first one goes dead', I think you'd have to hire a midget troll to sit in your battery compartment and switch the connections when he hears you cussing the dead trolling battery.  ;D

In order to keep 12 volts you would hook up the batteries parallel. Positive to positive and negative to negative. Just like putting jumper cables on a car. If you hook them up in series then you'd have 24 volts (think of flashlight batteries and how they stack in series with positive to negative).

Thanks for the info, I won't start hiring midget trolls yet.  Should I just return the 12v TM and get a 24v with more thrust.  I'm new at this, thanks for the input.

I also have a 19' f/g boat and I would not last half of a day with a 12 volt 40lb t/m. Depending on the water you fish, you would not be hurting to go with a a 70-82lb motor. I got the 70 pound and still find myself wishing I had went with the 82lber. I can get through a 8 hour day of pleasure fishing ok, but in a tournament I find myself a little too slow at the end of the day. If it is windy, then it happens way too early in the day for my taste.

The higher your voltage, the lower your amp output will be. Higher voltages will do the same amount of work with less amps, which in turn will allow you to have more time with the t/m in the water. Amp draw is what runs your batteries down. If you stay with a 12 volt system, you will have more staying power with two batteries as opposed to one, but still not as much as the 24 volt setup.

I replaced an old 12/24 MG with a 24v MK and I'm very happy with the new one. If I were you and could make the switch without much of a penalty I would do so. You will need a new plug and receptical.

You have got to be way underpowered with the new 40 pound minnkota.  That much glass boat you are needing 70 to 80lbs thrust on 12/24 v. system.  But now that you've done it, you can look around for a rebuilt TM - sometimes at a good price from a repair shop.  The shops rebuld the older ones as people ask for the latest models on their new boats.

I returned the 12v 40lb, it had not been installed.  I bought a 24v 65lb, can't wait to install it.  Thanks for all the advice.

texasfishin

I replaced an old 12/24 MG with a 24v MK and I'm very happy with the new one. If I were you and could make the switch without much of a penalty I would do so. You will need a new plug and receptical.

NBR, Can you fill me on the reason for switching out the plug.

I'm also runnig a 12v TM setup. What I do is run the TM on an A/B switch and run it on "ALL". This way I don't have to worry about switching over to the other battery. I can run all day and not come close to running out of juice.