Trolling Motor Upgrade Question

[CS1]

Looking for advice on a new Minn Kota. Currently have a Power Drive with iPilot and spot lock, 45 lb thrust. My boat is a Polarkraft 165. The current trolling motor seems a bit undersized. When trolling in any little bit of wind or current I can't run for much more than an hour. Current battery is a 24 series 70Ah. I have room for two 27 series batteries and there is 6ga wire running from the current battery to the existing Power Drive unit.

Should I go to 24v or stick with 12v?

What thrust should I move up to? I really want to fish the Detroit river. Wind & Current.

I also really want the upgraded spot lock.

[That Minnesota guy]

80lb. 24 volt.

[Marty59]

And 2 31 series agm's. Only 9#'s more per battery then 27 series

Marty

[ThreeDogsDown]

Agree with the guys above me. My boat is 18’ and I have two 31’s powering an 80# 24v Ulterra. Works great.


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[kswalleyer]

Originally Posted by CS1

Looking for advice on a new Minn Kota. Currently have a Power Drive with iPilot and spot lock, 45 lb thrust. My boat is a Polarkraft 165. The current trolling motor seems a bit undersized. When trolling in any little bit of wind or current I can't run for much more than an hour. Current battery is a 24 series 70Ah. I have room for two 27 series batteries and there is 6ga wire running from the current battery to the existing Power Drive unit.

Should I go to 24v or stick with 12v?

What thrust should I move up to? I really want to fish the Detroit river. Wind & Current.

I also really want the upgraded spot lock.

there are way smarter people on here with these electronics...but in my experience, If I trolled out of my bass boat(20'Ranger) in strong winds, I'd only get 2-3 hours tops out of a 112lb thrust 36v system...Not sure an 80 would necessarily get you what you want out of wind AND current?? or maybe it would....somebody else here probably has more scientfic approach than I did for the hours you might expect out of an upgrade....I imagine a kicker isnt an option on a 165? then you keep your current TM and use it to just steer all day long with no issues.

[Snowking]

I would for sure go 24 volt. Even more important fishing river system. Yes size 31 battery would be better. But in that size boat. Battery size and Weight would come into play. I think I would go with 2 size 27 battery’s. If your battery storage is not centered on the boat. I would set it up with one trolling battery on each side. To keep the boat balanced. If you decide not to spend the money on a new trolling motor. I would for sure upgrade that single size 24 battery to A single 31. Or go with two size 27s wired for only 12 volts. The 24 volt motors will use less amps. Then a two battery 12 volt system.

[MauroC]

A 24 volt 80lb terrova would give you more than you need. Get one with spot lock if budget allows. My 1775 Lund works great with this setup. Of course, in high winds ant TM setup will not work


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[therealjoeblow]

A 24v system will approximately quadrouple your run time. For 2 reasons:

1) You have 2 batteries instead of one, so double the amps available.

2) This one is more complicated, requires understanding of power vs current vs voltage and a bit of math. The motor is actually drawing power in Watts, but power capacity of the batteries is expressed in Amps. Current draw on the motor is also expressed in its specifications as Amps at max speed. Now at the same level of thrust, hypothetically a 12v motor and a 24v motor will draw approx the same number of watts. But electrically, Watts = Volts x Amps. So for the same thrust and power consumption in Watts, if you double your voltage, your are only drawing 1/2 as many Amps.

Therefore in total, you have 2x the battery capacity, at 1/2 the current draw, or (2/0.5) = 4x the run time for the same thrust level.

So you can use that extra voltage to either increase your run time, or increase your thrust, or a little of both.

in summary, a 24 volt system is significantly better across the board than a 12v system.

Cheers

[Grizz86@]

I have an 18.5' Hewescraft Sportsman 180 with an Ulterra 24V 60". I'm using two group 24 Marine batteries - all I could stuff under the floor on the center line with a Minn Kota onboard charger.



I fish a lot below McNary Dam on the Columbia. The current there will vary from .7mph to 2mph. I can run for two days without a charge and have zero problems running against that current. Chasing upriver to get above a snag I can manage 3mph on the bow mount



The only free flowing section of the Columbia is just north of me and is a mecca for Fall Chinook Salmon fishing. The current there can run 7+ mph and the bow mount won't pull my boat uphill against that.

[David Anderson]

Originally Posted by therealjoeblow

A 24v system will approximately quadrouple your run time. For 2 reasons:

1) You have 2 batteries instead of one, so double the amps available.

2) This one is more complicated, requires understanding of power vs current vs voltage and a bit of math. The motor is actually drawing power in Watts, but power capacity of the batteries is expressed in Amps. Current draw on the motor is also expressed in its specifications as Amps at max speed. Now at the same level of thrust, hypothetically a 12v motor and a 24v motor will draw approx the same number of watts. But electrically, Watts = Volts x Amps. So for the same thrust and power consumption in Watts, if you double your voltage, your are only drawing 1/2 as many Amps.

Therefore in total, you have 2x the battery capacity, at 1/2 the current draw, or (2/0.5) = 4x the run time for the same thrust level.

So you can use that extra voltage to either increase your run time, or increase your thrust, or a little of both.

in summary, a 24 volt system is significantly better across the board than a 12v system.

Cheers

Interesting. If you go from 12V to 24 Volt via putting 2 12 volt batteries in series one doubles the voltage however using the same battery that the original posted stated, a 70 AH you still only have 24V @ 70AH not 140 AH. Yes thrust can be converted to watts and the old rule of thumb was in a 12V motor 1 Amp = 1 # of thrust. So yes a 24 volt motor will have 1/2 the amps. Putting 2 batteries in series does not quadruple their capacity, it doubles the voltage and whether you have a 12 volt motor pulling 750 watts or a 24 volt motor pulling 750W, the second battery gives you twice the run time assuming the same load. Now if you are talking about putting 2 24V @ 70AH batteries hooked in parallel, I would agree with your post. I agree with your last 2 statements as 24 has less IR losses in the wiring because the current is 1/2.....assuming the original poster replaces the trolling motor with one that has the same thrust. It is likely that whatever 12 volt motor he has it will be replaced with a higher thrust 24 volt, say a 12 volt 55# verses a new 24 volt at 80#, therefore he will only be able to increase his battery usage by about 50%. Which leads me to agree with the others by using 2 series 31's which are usually 105 AH or 50% more therefore making up the difference from increasing the thrust.