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Volts Vs Speed?

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    Volts Vs Speed?

    What percent of speed increase can I expect by going to a 52V battery from a 48V battery?

    In short i think maybe 2 mph.
    But that is with a 52 volt battery at 58.5 volts. Full charge and same battery at 54 volts approx.of a 48 volt full charge. On a 20 ah battery (less sag under power) with a bbso2.
    But that is dependant on many factors. Aero bars above 30 mph have greater effect than battery voltage. Thinner harder tires are an advantage. Aero bars or fairing really boost top speeds most effectively. A 30 amp (bbshd) vs 25 amp bbs02 would give bigger boost with voltage. Bbshd with ludicrous controller could burn watts even faster. Keeping motor rpm above 60% of max rpm rating is neccesary to provide enough power to operate at higher speeds both to provide enough power and prevent motor destroying heat. Gearing is important if you intend on pedaling to assist in attaining higher speeds. A 52 ring and 11 cog is not effective until above 30 mph. (I do find much better range using this gearing at 25mph but accealeration is anemic and slightest hill slows it down) Much above that you will need even more agressive gearing to pedal. 130 rpm for bbs 02. 150 for bbshd are cadences at motors max rpm that i find are ineffective. But minimum of 70 is needed to supply power by motor. I try to keep cadence between 70 and 80. Power of motor drops off rapidly below a cadence of 50. And again just before max rpm. Acceleration is slow and watts are burned as heat not forward motion. At 1mph 97% goes to heat 3% is powering. You forward. At peak you get around 85%. Low speeds low gears.
    Downhill and wind at your back is ideal if you do not have a high wattage motor.
    Aerodynamics is real key 89.6 mph is record for human power, no assist. Not me.
    Hoping at least most of this is correct. And understandable.
    Last edited by Gr8fun; 03-16-2017, 09:27 PM.


      Part of the recent popularity of 52V systems is that 14S is the highest voltage that the BBS02 and BBSHD stock controllers will work at. They both have an amp-limit, so maxing the volts gives you the best possible power.

      if you use too high a gear, and also use max throttle all the time, you get the max power on the stock controller, but it doesn't help the heat any.

      however, if you use higher volts, it can be "possible" with careful throttle moderation, to get acceptable power with less amps, and that means the motor would run cooler


      • Gr8fun
        Gr8fun commented
        Editing a comment
        Looks like i will be putting on heat sensor
        No more room on Handle bars
        Cadence sensor.
        Heat sensor(next).
        Batt man.
        Bafang display.
        Three shifters -- igh ,cassette and dual front rings.
        Aero bars, not yet
        Camera, not yet
        Cell phone holder

        Cell phone holder