How it works

1. What's in the box...

Included with the GravityLight unit is the drive belt, two hooks, two bags for the weight and two large zip ties.

2. Install the unit

Using the zip-ties the unit should be fixed to a beam, ideally at the edge of the room. Rotate the unit to direct the light where needed and thread the drive belt through the slot at the base.

3. Fill the bags

The larger bag is filled with sand/rocks/dirt to approximately 12kg (a red light will indicate overload). Fill the smaller bag to enable smooth rewind.

4. Lift the weight

Once the unit is installed, attach the hooks to the drive belt. Hang the large bag on the right, the small bag on the left and simply lift up the larger bag by it's orange handle as high as you can...

5. Attach additional lights: SatLights

Light can be spread around the room or focused on a particular activity by attaching SatLights to GravityLight. Several of these can be daisy-chained around a room.

6. Clean, safe light

... depending on which brightness setting you choose, a 3 second lift generates up to 25 minutes of light. Once the bag reaches the ground, simply lift it up again.

You can also watch the guides for installing GravityLight and attaching SatLights below:

How does it really work?

Potential Energy

GravityLight is installed to provide a 6ft/ 1.8m drop of a 12kg weight. This weight is lifted and on release starts falling very slowly (about 1mm / second).

Kinetic Energy

This movement powers a drive sprocket, which rotates very slowly with high torque (force). A polymer geartrain running through the product turns this input into a high speed, low torque output that drives a DC generator at thousands of rotations per minute.

Electricity and Light

This generates just under a tenth of a watt, a deciwatt, to power an onboard LED and ancillary devices. Given the ever-increasing efficiency of LEDs, this produces a light over 5 times brighter (lux) than a typical open-wick kerosene lamp.

Once the weighted bag reaches the floor, which depends on how high it was installed, it is simply lifted to repeat the process.

See the technical specs for version 1: GL01