Trolling motor battery conections/wiring

[fishbig]

On a 12 volt trolling motor what is the best way to set up a system where I can have 2 batteries and be able to switch when one gets low? I fish several days at a time and cant always charge the batteries each day. I would like to have a back up that is easily switched.

[barnstormer]

Most battery stores carry Perko switches for doing just what you want. Go from Batt. 1 to Batt.2, or both Batts. Use nice big wire, the more strands the better, good conectors.
For a charger I use a ProMariner,, ProMite. You can get 1,2,3,4 battery models. They direct the power to the lowest battery and then when all batteries or charged, drops the amps down to a float charge. They are not cheep but then neither are batteries, and if not taken good care of, will not last as long. They will pay for themselves in time.

[Starfish]

Another option to consider is to simply connect your two batteries in parallel instead of switching them. True that you won't be able to switch to a fully charged battery, but your capacity will be doubled, and under normal circumstances you won't be discharging either of the batteries as deeply so you will actually get longer overall battery life (i.e. discharge-charge cycles will be less damaging to your batteries). And all it takes is a couple of feet of wire.

[Fishnchips]

A simple toggle switch and 12v lamp between the batteries in parallel work well and it's cheap. The light bulb will control the current from one battery to the other.

So you can switch "off", troll as long as you want on the #2 battery. Then start the engine and the battery #1 starts charging, then switch the toggle switch to "on". Battery #2 then starts charging in a very smooth manner through the light bulb. When the light goes out, your battery #2 is fully charged to the level of battery #1.

No big sparks, no high current, no expensive equipment.

[Seon]

You can wire your batteries like this

[sucker]

I have two trolling motor batteries with a switch right, left, and both. I like to use the both as the current draw on each battery is halved which is easier on the batteries.