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Thread: amps vs pounds of thrust

  1. #1
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    Default amps vs pounds of thrust


    who's got the formula for sizing battery by hours of operation. I had it but it's in never never land.. help pm me if its long

  2. #2
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    There is no universal formula. It varies with boat weight, wind, current, hull type, fishing type and a few other things. You can guess by taking the current used, which isn't a trivial thing to measure on a variable speed motor, and figuring the battery will give you 25A for however many RC it is rated for and SWAGing the RC at your measured current, but even the stopping point is just a guess.

  3. #3
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    no there is a formula I use to have it nothing is writen in cement

  4. #4
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    here's what I've been told by cc member AMPS X 0.6 =MINUTE'S DIVIDED BY 60 = HRS........OKAY GUYS LET ME KNOW WHAT YOU THINK...

  5. #5
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    12 volt system = 1.2 amps per # of thrust
    24 volt system = 0.9 amps per # of thrust
    36 volt system = 0.55 amps per # of thrust

    So, pick system and use that value in the formula;

    Amps per # of thrust (0.9) x max #'s of thrust (80) x the % of speed setting (setting of 5 on 1 to 10 would be 0.5)

    So... .9 x 80 x .5 = 36. 36 amps per hour running at speed setting of 5

    Divide amp hours on battery (fully charged) by 36.

    675 / 36 = 18.75

    So my 80 # thrust 24 volt system should run just under 19 hours.

  6. #6
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    19 hrs at setting of 5.

  7. #7
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    Ya'll might wanna listen to Catfan. He knows a thing or two of what he speaks.

  8. #8
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    About that 675AH battery......it probably weighs about 450lbs.

  9. #9
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    Sorry about that, looked at crancking amps. AH = 115 each battery so 230 /36 = 6.4 hrs at half max speed. Boat can hold 500 lbs batterys. It would be a nice boat though.

  10. #10
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    Isn't thrust measured from dead still and does not compensate for current, wind, or momentum! So there can not be an accurate formula. Not to mention voltage/amperage loss along wires and connectors. Plus as the battery charge drops to say 80% it demands more.

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