Weight driven DC motor design help (energy storage)?

Hi I need help figuring out how to connect a falling weight to my various DC motors and PMA's to charge a battery (with charge controller) I plan on using the excess solar/wind to drive the weight up when it's available, then release the weight to drive a motor and charge my batteries as a backup for when it's cloudy and there's little sun for my solar array system.

Most of my motors are geared and have a toothed gear that connects to them how do I arrange things to spin the rotor with a falling weight through the use of a chain sprocket, do I need some sort of pulley system how do I set this up and mount everything?

5 Answers

  • paul h
    Lv 7
    12 months ago

    The simplest method would be to convert/adapt a grandfather clock mechanism to your motor/generator. At least you can get some idea of how to ramp up the gearing/mechanism to a larger scale if it works as you need.Not likely to produce much power but may be OK for smaller scale/charging. I had a similar idea to attach a rope or cable very high up to very large trees that I plan to fell and use the falling weight of the tree to turn a heavy flywheel in turn to produce power/charge batteries.


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    Or convert a Heron's siphon pump/fountain to run continuous and power a small turbine...


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  • 12 months ago

    As others say, it is an incredibly inefficient system & needs a massive weight to equal the capacity of a relatively small battery pack.

    However, to use the weight system, purely as a theoretical method:

    You could use a differential (as in a vehicle axle, full size or model scale) with the motor and generator connected to the wheel shafts.

    The weight drum or pulley would connect to what is normally the drive shaft side.

    The motor can wind the weight up, the generator would try to turn the opposite direction as long as there is a pull on the weight drum/pulley.

    Use a brake of some sort on the generator shaft to stop it from turning when you do not want to generate power.

    The motor side would need a ratchet or pawl to prevent it being spun backwards by the weight when not being used.

    The same system would work with a gear or vane pump instead of the weight winding drum for storing energy by lifting liquid or compressing gas.

  • 12 months ago


  • 12 months ago

    waste of energy. It's much more efficient to charge the batteries directly from the wind turbine or the solar cells. Batteries are made to store energy directly.

    You would wind up with a large inefficient apparatus that serves no purpose.

    Sort of like using the output of a solar cell to drive a motor which drives a generator that charges the battery.

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  • 12 months ago

    The mechanical setup is entirely your problem, and will depend on a lot of factors.

    But: using a mechanical energy storage to charge batteries is extremely inefficient, as opposed to charging the batteries outright or using the power from your mechanical storage directly.

    And: you'll need a big weight and a high tower. 1 kWh, about the content of a reasonably large car battery (about 90 Ah), is 3.6 * 10^6 J. With a 100 kg weight, you would need a drop of 3600 meters. Use a fully loaded semi at 36 tons, and you only need to drop it by 10 meters :-)

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