Quote:
Originally Posted by NoBozo
I seem to remember a simple electrical principle from my studies some 40 years ago. This principle still works today as far as I know. If you raise the voltage in a supply line (Picture the overhead lines you see supplying power to the GRID).....you can REDUCE the amperage....which allows you to REDUCE the WIRE SIZE..therefore lighter weight...and still have the same power at the end of the line. Correct me if I'm wrong.......
This seems to me to be the case with this Trolling Motor. Having lighter wire seems to be a good thing...NO..??  NB |
You are correct vis-a-vis supplying power like over the electric grid. IF the power is constant, a higher voltage reduces the current supplied. Of course there's some limits on how high the voltage can go ... but you remember correctly. In the case of trolling motors what's happened is that over time more powerful motors were wanted (boats got bigger and heavier I guess). This lead to very high currents and large wires at the old 12V standard. At some point they couldn't make a more powerful 12V motor and so 24V and 36V systems were designed.
In this case the TM manual says to expect a current = to 0.75 times the thrust. At 64 lbs this gets the OP about 48A current draw. With the wires he has this should be safe but he'll "lose" something like 1.3+ V in the wiring so IF he had exactly 24V at the battery terminals, he'd have 22.7V at the TM itself. I think the manual wanted the voltage loss to be 1V or less. The way to do this is with thicker (AWG) wires or more wires (of the same size). Doubling up on his AWG8 wiring would give the equivalent of using AWG5 wiring. That's a bit better then the AWG6 recommended at the fishing sites I looked at. It's more $$ but you get slightly better motor performance and more reliability. Then again how often will F'n'J be running his TM at full power ?