GravityLight is an innovative device that generates power using the force of gravity from a weight. Made up of three parts, the light is hung above the ground giving the weight component a 6ft drop. To power the light the weight is lifted, and on release starts to fall slowly back down towards the ground. This movement powers a series of gears which rotate very slowly with high torque (force). The gear train running through the product turns this input into a high speed, low torque output that drives a power generator at thousands of rotations per minute. This output is used to power an LED light, and ancillary devices, providing off-grid communities with access to energy.
With the 0.1W of power it generates, GravityLight provides a light superior to kerosene lamps and can also power other devices, such as a radio. You will find a DC jack at the back for connecting SatLights and/or other devices. If you're experimenting we’d love to hear what you discover, so please email us at firstname.lastname@example.org.
To this question there are two answers: the power output of the GravityLight in Watts, and the light output of GravityLight in Lumens.
The power output of a 12.5kg load is 0.075W
The Light output is 16 Lumens
The advantage of an LED light source over a kerosene lamp is that nearly all this light output can be directed at a task or onto a surface. This idea of ‘useful light’ requires a more appropriate unit of measure than ‘Lumens’ (total light output). Lux is the unit for light falling on a surface (lumens/square meter). For comparison, when used to illuminate a workspace, a GravityLight SatLight can provide up to 35 Lux. In the same setting, a basic kerosene lamp can only provide about 6 Lux.
Our first prototype, GL01, was the first mass-produced iteration of GravityLight. Several thousand were made to test the concept demand and feasibility through trials in off-grid homes across 26 countries.
From the extensive learnings and insights from the trials and 18 months of further development, testing and verification we now have an improved Gravitylight, GL02. The key principles remain - it offers instant power, on demand, without the need for batteries or the sun - but GL02 can now be used by anyone, regardless of height or strength, is more robust and efficient.
We are currently in the final stages of planning our launch and we will be able to provide you with details of how to purchase your own GravityLight in the near future.
The best ways to stay up to date with the launch -
Great news! We are interested in hearing from organisations already involved in distribution of products to off-grid households in sub-Saharan Africa and Asia.
Please share more about you and your organisation in this form and we will get back to you about future opportunities, once GL02 is launched.
Thanks for your interest! Check out the 'We're Hiring' section of our website (under the 'Contact Us' tab). If that page is not there then unfortunately at the moment we are not currently recruiting but, to be kept up to date with any future opportunities, we recommend you follow us on Facebook and Twitter, or sign up to our [newsletter].