How long will my battery last at different speeds?

RTDcanuck

Seaman Apprentice
Joined
Jun 27, 2001
Messages
43
I'm buying a 12V trolling motor with five forward speeds and two reverse at each speed how long will my motor last and which speed would u recommend to get my battery to last the longgest? it's for a scott canoe i'm using it as the main motor what speeds would u recommend me to use to get the longgest life out of my battery between charges?
 

Drowned Rat

Captain
Joined
Jan 20, 2004
Messages
3,070
Re: How long will my battery last at different speeds?

Trolling motors with set forward and reverse speeds like this one manage their speed by wasting energy in the form of heat. Therefore the most efficient speed is the highest speed. The slower speeds produce less thrust and waste energy.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: How long will my battery last at different speeds?

Moving to Electronics and Trolling Motors.
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: How long will my battery last at different speeds?

If I had to guess, I would say it should run all day on the full setting for your light boat. Maybe even on half speed. Take an extra battery for safety and try it out.
 

Ralph 123

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Jun 24, 2003
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Re: How long will my battery last at different speeds?

The amount of energy in a battery is usually designated in Ahr - Amp hours. It is how long, in hours, the battery will provide 1 amp of current at the rated voltage.<br /><br />Now, look at the specs on the motor and see how many amps are drawn in the 5 different speeds and do the math.<br /><br />Example:<br /><br />Assume you have a 100 Ahr battery and the the motor draws 1 amp at 1, 2 amps at 2, etc<br /><br />so then, assuming ideal characteristics<br /><br />at speed 1 it will last 100/1 = 100hrs<br />at speed 2 it will last 100/2 = 50hrs<br /><br />and so on.
 

cobra 3.0

Lieutenant Commander
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Jul 31, 2003
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Re: How long will my battery last at different speeds?

Ralph's got it right! At slow speeds it can last for days. On full out, a few hours.
 

ndemge

Commander
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Jul 15, 2002
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2,644
Re: How long will my battery last at different speeds?

cobra... ralph was giving hypothetical example...<br />need to read the thing and see what it does. (or hook a meter to it)<br /><br />if it wastes a lot of energy at low speeds, it makes no sense to use low.
 

ebbtide176

Commander
Joined
Jan 22, 2002
Messages
2,289
Re: How long will my battery last at different speeds?

it should last the longest on the lowest speed.<br /><br />the diff settings will make use of diff connections within the windings of the motor. (or all the TM's i have seen were like this design) this will pull diff amts of current, along with giving more speed. <br /><br />the currents pulled will be diff for each setting, i can almost guarantee that. it will make all the world of a diff in how long the battery will last, as it is rated in how much total current it can provide. just my 2c :) <br /><br />the only thing (i can think of) that would use the same current on all speeds would be a TM that is just using resistors in parallel to 'bleed' off some of the current (like some lamps work). but that would be extremely stupid engineering it seems :D <br /><br />you should use a deepcycle battery.
 

18rabbit

Captain
Joined
Nov 14, 2003
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3,202
Re: How long will my battery last at different speeds?

Ralph – you nailed it. And in real life applications you would also divide the deep cycle battery’s A/Hr rating by 2…to prevent discharging the deep cycle below 50% of its capacity.
 
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