I'm trying to design a jigging machine for a fishing boat, using a RaspPi as the controller. (A jigging machine jerks a 1kg lure up and down near the sea bed, and pulls in a fish when it's hooked.)
The motor I'm hoping to use is here: 3336_0 - 86STH156 NEMA-34 Bipolar Gearless Large Stepper and the supplier recommends I recommends I use a 24V supply.
However, the boat I want to fit the machine to has only 12V. I'm trying to assess the pros and cons of different approaches.
The simplest solution is to just use a 12V supply to the motor. I understand I'll need thicker wires to supply this. I'm thinking that using 12V will generate more heat and produce less torque. There will be times that the machine will need to pull up several fish at a time from 50m deep - say a 20-30 kg load. And sometimes the hook will snag the bottom. I'll include a current monitor, so I could limit or cut the supply when there is too much load. I don't know how often this might happen till I try it though, and how inconvenient it would be.
I've ruled out having 2 batteries, in parallel when the engine is running and in series when the engine is stopped, using solenoids to switch - the engine is often left running while the boat is fishing, as it needs to continually drift with the tide/wind, then motor back up to the spot where the fish are.
So I think the only other option is to buy a second battery and wire in series, swap the 12V alternator for a 24V alternator, and have something that supplies 12V from the 24V for the GPS, radio etc.
Naturally, I'd favour the first option, but I wonder how important a 24V supply would be for the jigging motor, and how much we'd lose out going with the 12V option.
Thanks for any further input on my inputs quandary.