24v or 12v motor? Info right from the Manufacturer

For those contemplating a 12v or 24v motor, it seems that, contrary to what some believe, "Bigger" is NOT always "better".


There was a "Discussion" contained within a post "debating" the Advantages of buying a 12v motor vs a 24v motor.

I presented my thoughts on Run Time, but they were countered by several members and the post was closed.

I emailed Minn Kota the below information (same info I had presented in the post) and they got back to me with the reply that is posted at the bottom. It seems the folks at Minn Kota AGREE with my theory on the amount of run time with a 12v motor and 2 batts vs a 24v motor and 2 batts.

This is what I sent to Minn Kota:

Hello,
I'm looking to get a Riptide transom motor and not sure which is best for me. I know that I will never need more then 55lb thrust, but every one says to get 24volt as they have more "run time". From my figures below I don't see how, if I have 2 batteries for either motor, this could be possible. I could see it if the comparison is having just one battery with the 55lb and two batteries with the 80lb. I see that the 80lb model has a max amps draw of 56. If this is where 80lb is produced then I am guessing it will take about 38 amps to produce 55lbs. (56/80) to get amps/lb then multiply by 55 to get 38.5amps If I get the 80lb and (2) 100A/H batteries I figure I could run approx. 2.63hrs (100/38). I see that the 55lb model has a max amp draw of 50amps. If I get the 55lb model and (2) 100A/H batteries I figure I could run approx 2hrs (100/50) on each battery for a total of 4 hrs. (vs 2.63 with the 80lb) I know that batteries will degrade and I will likely never get the full 100A/H out of them, I just wanted to use round numbers for equal comparison. Are my figures correct? Since I will never need more then 55lbs thrust and the 55lb model is cheaper then the 80lb can you tell me if there are any other advantages to getting the 80lb model?

Awaiting your reply Thanks - Rob

This is the reply I receive back today:

Rob-

Thank you for your inquiry to Minn Kota. I agree with everything you have figured out as far as run time and differences between the 55# and 80# motor. If you run a 55# motor with two batteries as apposed to an 80# set up on 24 volts there is not doubt you will get more run time out of the 55# motor. As long as the boat is not too much weight for the motor to where you will be running it on higher speeds the whole time I would go with the 55# motor. That motor can efficiently handle a total weight (boat, motor, gas, gear, people, etc.) of 2700 lbs.

Thank you,

Marc Collins

Johnson Outdoors

Here is the initial post:
http://www.crappie.com/crappie/mecha...ng-motors.html

Thank you Rob for the information and clarification from MINN-KOTA. Eric

You miss the point tho. You aren't comparing apples to apples, no where close. I ran a 55 pound minn kota on a 17 foot glastron pulling cranks using 2 large 12v batts. Doing everything I could do to conserve juice I would only get 5 hours tops in good conditions pulling at 1.8 mph. With the same boat an 80 pound was pulling it for over 8 hours maintaining 1.8.
I ain't no lectriction or nuttin but 8 hours is more than 5 here on Mississippi.
Hands on practical application is where it counts.

I had a 170 lowe 55 lb edge mk. one battery would not last all day in the wind and went to 2 bats to make it. Now have 80lb no comparison and its on a G3 176 alot heavier rig and i run it less than half of what I would have with a 55. a 55lb thrust on a 2700 lb boat would work ok if you had a calm day and were fishing in your backyard sitting on your trailer, my boat will run 3 mph with the troller would never go to anything smaller

Im going to explain this real simple once again since Rob keeps leaving the voltage part of the equation out in his figures. A 24 volt motor only uses half the amps to produce the same thrust as a 12 volt motor. Since it only uses half the amps as the 12 you must double the 24 volt run time to make this equation correct which puts it at about 5.3 hours compared to 4 hours for the 12 volt in parallel. This all has to do with resistance as the more voltage you have the less resistance you have and therefore the more efficient the system. Please refer to the formula from crappie101 and the reserve capacity info from the article off the western bass site.

You're wasting your time, Handi. :banghead:

Cane Pole explained this theory a few years back on a post also.

Here it is broken down in simple terms again. This is simple enough for anyone to comprehend. And by the way, bigger is better.

Minn-Kota also told me, a few years ago that I needed 2 lbs. of thrust for every foot of boat, so therefore the 40lb thrust I had at the time should have been plenty on my 17 footer,NOT.just saying

1) your goober at MK is mistaken.

2) as long as you leave the V out of ohm's law you are never going to get it.

3) again, them AH's don't evaporate on that second battery in a 24v system.

4) I noticed that you never commented the other night, on my post referencing your own calculations showing more wattage output at lower amperages using 24v.

here's info right from the SAME MANUFACTURER
and as it has been STATED you are not comparing apples to apples !!!please note the BLUE MARKS !!!these are the motors I am familiar with and that I use ,I do not use a transom mount motor that you and the minn kota guy are talking about I have no use for one!!!

here is freshwater motors

http://i977.photobucket.com/albums/a...ps8ffedd5a.png

here is saltwater motors

http://i977.photobucket.com/albums/a...psec477929.png

Wow! The 101 has almost twice the thrust and pulls a few less amps. Imagine that!

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Originally Posted by ATM

Wow! The 101 has almost twice the thrust and pulls a few less amps. Imagine that!

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And if you put those same 3 batteries in Parallel for the 12volt you will have 3 times the available A/H

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Originally Posted by Handicrappie

Im going to explain this real simple once again since Rob keeps leaving the voltage part of the equation out in his figures. A 24 volt motor only uses half the amps to produce the same thrust as a 12 volt motor. Since it only uses half the amps as the 12 you must double the 24 volt run time to make this equation correct which puts it at about 5.3 hours compared to 4 hours for the 12 volt in parallel. This all has to do with resistance as the more voltage you have the less resistance you have and therefore the more efficient the system. Please refer to the formula from crappie101 and the reserve capacity info from the article off the western bass site.

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I'm not leaving the voltage out. Why would you double run time for 24V? IF you put the batteries in Series Current stays the same, but voltage doubles. If you put the batteries in Parallel the voltage stays the same and the Current doubles.

P= I x E = P = E X I

So 2400Watts = 24volts x 100 amps which also equals 12 volts x 200amps, right? This is how the amps doubles when in 12 volt mode.......or if you want to figure it the opposite this is where the 100A/H "disappears" when in 24volt.

If you had (4) 6volts batteries you would have 400amps available when in parallel or you would have 100amp available when in series to give 24volts.

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Originally Posted by ATM

1) your goober at MK is mistaken.
Funny how all my facts are wrong, but your are all right
2) as long as you leave the V out of ohm's law you are never going to get it.
Please see above in Ohm's law to get the same result, if you multiply "E" by 2 then you must "Divide" I by 2 to get the same number
3) again, them AH's don't evaporate on that second battery in a 24v system.
Look above and you will see how this happens
4) I noticed that you never commented the other night, on my post referencing your own calculations showing more wattage output at lower amperages using 24v.
I think you are smart enough to figure out why I did not reply....(the thread got closed)

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So if Cane Pole comes on here and says that in Ohm's Law if 2400w = 24volts x 100amps, which also = 12volts x 200amps will you believe me?

Goober, I'm getting blue in the face. Look above at YOUR last sentence. According to YOUR own arithmetic it takes twice the amps to produce the same watts at 12v versus 24v. 24v IS MORE EFFICIENT!

For the life of me I can not grasp what is confusing you. You have the math down pat, yet time and time again you come to the wrong conclusion. If we both have 2) 100 AH batteries. All things being equal, except I have 24v and you have 12v, you are going to pull twice the amps, and I'm going to go twice as far. Look at the MK chart above. It's NOT lying.

One more time. According to your last sentence, you are burning through them AH's at twice the rate at 12v than I am at 24v.

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Originally Posted by ATM

Goober, I'm getting blue in the face. Look above at YOUR last sentence. According to YOUR own arithmetic it takes twice the amps to produce the same watts at 12v versus 24v. 24v IS MORE EFFICIENT!

For the life of me I can not grasp what is confusing you. You have the math down pat, yet time and time again you come to the wrong conclusion. If we both have 2) 100 AH batteries. All things being equal, except I have 24v and you have 12v, you are going to pull twice the amps, and I'm going to go twice as far. Look at the MK chart above. It's NOT lying.

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Not sure why you feel the need to start name calling.

According to my last sentence, in 12volt, you will have TWICE the Available AMPS with 2 batteries, in my original post I say that the 12 volts motor will definitely use MORE (50 vs 38 for the 24v) but not TWICE as MUCH, so the 12v will last longer.

Hopefully Cane Pole will open up this post and weigh in, especially what I just said.

I agree that if I have ONE battery using up 50amp, and you have TWO batteries (wired 24v) using just 38 amps YOU WILL GO FURTHER, but now add that 2nd battery into the equation with the 12v motor
IN 12v THE AVAILABLE AMPS is DOUBLE, assuming we both use 2 equal batteries.

Quote:

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Originally Posted by Handicrappie

Im going to explain this real simple once again since Rob keeps leaving the voltage part of the equation out in his figures. A 24 volt motor only uses half the amps to produce the same thrust as a 12 volt motor. Since it only uses half the amps as the 12 you must double the 24 volt run time to make this equation correct which puts it at about 5.3 hours compared to 4 hours for the 12 volt in parallel. This all has to do with resistance as the more voltage you have the less resistance you have and therefore the more efficient the system. Please refer to the formula from crappie101 and the reserve capacity info from the article off the western bass site.

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Handicrappie - I know you're getting a bit unsettled trying to "explain" your rational, but can you just answer the below 2 questions?

1) With (2) 12v 100A/H batteries, wired in Series to give 24volts, How many A/H do you have available?

2) With (2) 12v 100A/H batteries, wired in Parallel to give 12 volts, How many A/H do you have available?

Good luck to you.

Not sure why you feel the need to start name calling.

First of all everyone is a goober in here at one time or another , Second. get two identical boats put 55lb 2 battery on one. 80 lb 24 volt on the other. put them both on wide open and the 24 volt will go longer,faster and farther everyday of the week. Its apparent you have never had a 24 volt or been around one, if you had you would have never have started this thread.

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Originally Posted by clfarms1

Not sure why you feel the need to start name calling.

First of all everyone is a goober in here at one time or another , Second. get two identical boats put 55lb 2 battery on one. 80 lb 24 volt on the other. put them both on wide open and the 24 volt will go longer,faster and farther everyday of the week. Its apparent you have never had a 24 volt or been around one, if you had you would have never have started this thread.

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Best post on this thread.....well said

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Originally Posted by ATM

Good luck to you.

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Why did you change your post from what is below? Did you post and then realize in 24v you really DON'T have 200A/H, but just 100A/H?

Quote:

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Originally Posted by ATM

If we both have 2) 100 AH batteries, we each have 200 AH's to use. You just burn through the AH's twice as fast at 12v as I do at 24v. My second battery is there for the AH's and the voltage. My additional AH's do not EVAPORATE at 24v, just like yours don't at 12v. Look at the above MK chart. I swear it is not lying. 24v and 36v is more efficient than 12v. Ohm's law.

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Quote:

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Originally Posted by clfarms1

Not sure why you feel the need to start name calling.

First of all everyone is a goober in here at one time or another , Second. get two identical boats put 55lb 2 battery on one. 80 lb 24 volt on the other. put them both on wide open and the 24 volt will go longer,faster and farther everyday of the week. Its apparent you have never had a 24 volt or been around one, if you had you would have never have started this thread.

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Not sure who you are referring to, but the O/P did not do any namecalling

In ref to starting this post I have owned in excess of probably 25 different electric motors, I presently own (2) 12 volt motors and (1) 24 volt motor so I do have some kind of idea what works in my situation as not all situation are the same.

Not sure why you feel the need to start name calling
Not sure who you are referring to, but the O/P did not do any namecalling

I was trying to be nice but if you couldnt figure out that was from your post ,then I offically move you to head goober. Im sure that that set up that you want to do will work fine for you and if it dosent you will already have the 2 batteries that you need to go to a 24 volt set up.

Quote:

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Originally Posted by clfarms1

Not sure why you feel the need to start name calling
Not sure who you are referring to, but the O/P did not do any namecalling

I was trying to be nice but if you couldnt figure out that was from your post ,then I offically move you to head goober. Im sure that that set up that you want to do will work fine for you and if it dosent you will already have the 2 batteries that you need to go to a 24 volt set up.

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Where in my post did I do ANY name calling?

And I KNOW what works for me. The 24v motor is best on my 20' boat and the 12v 55lb thrust works best on my 16' boat.
If I had asked the question, as the original post referenced, I would have been pissed off if I had followed the board advise and spent an additional $300-400 that I didn't need to spend.

I think that about wraps it up...........this thread is closed