I’ve got 3 batteries on my boat: 2 for my 24v trolling motor, and 1 for cranking my engine and running the accessories. I don’t want to risk not being able to crank the big motor if I leave the radio, DF etc on too long. Can I take the 2 wires from the cranking battery that run to the fuse block and neg bus for the accessories and tie them into one of my trolling batteries? The batts are rigged in series so I’m not sure if the 24v would be too much for the fuse block. I called MinnKota and they said it could be done but they wouldn’t tell me how for liability reasons. Any advice would be much appreciated!
Power the fuse block with leads from positive/negative terminals of the same battery. You only get 12 volts to the accessories and still maintain 24 volts to the TM … 
be careful… 12 or 24 volts isn’t a lot, but believe me, with a big battery behind it it is enough to vaporize wires in yo’ face if you cross the wrong ones!
What reelly old said will work. may not be the best for your batteries, since you will effectively be discharging and them at different rates even though they are in series as far as the main load (trolling motor) is concerned. It shouldn’t normally be much of an issue, but if you were to run your accessories for a long time without running your trolling motor, as soon as you start the trolling motor again the battery that wasn’t being used will essentially start charging the battery with the accessories connected in an uncontrolled manner (possibly with a LOT of current) if the voltage has dropped significantly. Probably not going to do any real damage in the short term unless you heavily discharge one battery, but probably not good for the longevity of your batteries either.
That being said, I would still do it that way. I don’t think there is much of any other option, unless you go to four batteries. And that’s a whole nuther can of worms.
Angler 204 FX
Yamaha 150
Make your self a short set of jumper cables and use them when you cranking batery wont start the outboard then hookup to only 1 of your 24V trolling mtr. set up +to+ -to- .If you have a good group 27 cranking battery it should run all of your electronics all day and still have plenty of power to stsrt 300 hp, I use mine 4 day a week and never have charged the main battery or had to jump it.The alt.on these new motors charge quick!
I carry a set of jumper cables. Have fished all nite with the radio,live well, and lights on and it didnt run the battery dead. If you add up your amps per hour for all of your electronics its not that much especially if you are running the motor every few hours to move to another spot.
Thanks everyone. All provided very sound advice. All 3 of my batteries share one compartment so I’m thinking I’ll leave it as-is and just jump the main motor if it’s ever needed. I use a handheld GPS and VHF so the only accessory draw on the batts will be the DF and livewell/bilge pumps. Maybe I was over thinking the draw on the batts. At least now I have several options ot get me out of a jam. Much appreciated!
best option may be, leave everything hooked to main battery, and install a perko to one over teh trolling motor batteries, and use the perko only if the motor wont start, then you arent regularly discharging the deepcycles at different rates
quote:You can take the positive and negative wires from the fuse block and connect them to one of the batteries that are wired in series for the trolling motor.
Originally posted by Local ClusterI’ve got 3 batteries on my boat: 2 for my 24v trolling motor, and 1 for cranking my engine and running the accessories. I don’t want to risk not being able to crank the big motor if I leave the radio, DF etc on too long. Can I take the 2 wires from the cranking battery that run to the fuse block and neg bus for the accessories and tie them into one of my trolling batteries? The batts are rigged in series so I’m not sure if the 24v would be too much for the fuse block. I called MinnKota and they said it could be done but they wouldn’t tell me how for liability reasons. Any advice would be much appreciated!
You want to connect to the battery that has it’s negative terminal connected to the boat’s negative or ground, not the other one. There will be 12 volts between the two terminals of the same battery. You won’t have 24 volts to the fuse block.
This is something you might be better off having done by someone with experience in boat electrical wiring. And make sure to install overcurrent protection to protect the wiring.
Ron
2000 Camano Troll
North Charleston, SC
I carry jumper cables for this. Jump main off TM if necessary. Chris’ idea is cleaner.
Gotcha Covered,
Lee Strickland
Strickland Marine Insurance Agency, Inc.
https://stricklandmarine.net
843-795-1000 / 800-446-1862
I just added another starting battery with Perko switch for that reason
TM batteries are in the console and starting and spare battery in bilge and the switch is on those
Sea Pro 210cc
Yamaha 200 4 Stroke
Dodge 1500 4x4 HEMI
I was astonished that my 225 merc cranked ist pull of the rope when my battery went south!Would have never beleved it but had no other choice!