SociaLite Lighting Systems Inc

Engineering for the Middle of Nowhere

Technology


Overview


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We set out to design a solar powered lighting system for assembly, installation, operation, maintenance and repair by the inhabitants of impoverished communities; a solution to accommodate their culture, their environment, and the materials available at the point of use.

We dreamed of a truly technological, financial and operational self-sustaining system—accessible from income and location perspectives, maintainable when viewed from locale, cost and complexity, durable from considerations of culture, climate and usage. Coincident with the engineering is a desire to make available an accessible light source to the 1.6 billion people inhabiting regions devoid of the infrastructure we take for granted. From the outset, the sharing of expensive items such as imported photovoltaic panels and car batteries significantly reduced the overall system cost. Our initial prototype, battery powered lanterns recharged weekly at a central charging station has evolved into a more versatile community mini grid with facilities for lantern and cell phone charging, video projection and high power audio. A typical system comprises a 100W photovoltaic panel connected to a 75Ah marine lead acid battery through a MPPT charge controller with up to 30 DC outlets.
SociaLite System

The mini grid, supplied as a self-contained kit for the manufacture of a lighting system, is designed to fit into a large duffle bag—a lighting system in a suitcase. Included are all the necessary tools, instructions as pictograms and videos in local languages, lantern and charging station components, a PV panel, audio amplifier and pico projector. To this are added the locally sourced lantern housing materials, a car battery and the lantern batteries—the complete system ready for delivery—on a pick up truck, someone’s head, a bicycle or the back of a donkey—a functional manufacturing and supply chain.
Supply Chain
Working with our advisors and community groups in which the end-user assumes significant responsibility for system implementation comes with the promise of self-sustainability—an approach fundamentally different to many organizations. Characteristics common to many of these ventures include light sources developed and manufactured far from the place of use; local infrastructures for the maintenance and repair of these systems that do not exist and cannot be created; equipment often sold at less than cost price with subsidies from unsustainable sources; systems that are otherwise unaffordable to those for whom they are intended—the rural poor.

The Lantern

Initial designs for the lantern circuitry were simple—comprehendible by those with a high school diploma. However, they were inefficient with separate circuitry for the LED driver and battery charging functions. A microprocessor increased the complexity, but gave us a single board with required functionality and firmware field upgradable. We now have a circuit that functions indefinitely in the deep bush. We continue to use through hole circuitry—the board can be assembled by those unfamiliar with a transistor or a LED; end-users more directly connected to the technology, comprehending that they are able to fabricate their own lighting system—and repairs are possible.
Powered by 4.5 Ah, 6V lead acid batteries, the lanterns run at full power for about 40 hrs (reduced power for about 120 hrs), only requiring a weekly recharge enabling each outlet to support up to 7 lanterns.

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We initially used bamboo for the lantern housing with an empty plastic juice container for the diffuser. However, the bamboo split easily, clay substitutes proved too heavy, molded plastic expensive and fragile, and, once broken, irreparable. A variety of designs using cans and gourds for the housing body followed before undergraduate students in Ghana and Rwanda independently employed a robust, plastic hair relaxer container to host the battery and circuit. Two bicycle spokes connected this base to a translucent bottle for light diffusion with a third spoke used for the handle—this design proving to be very effective. Unavailability of the original juice bottle has forced us to substitute a slightly more opaque antibiotic container—both containers remain relatively easy to source in larger towns.

Always room for improvement, the overall lantern design continues to prove very robust from electrical and mechanical perspectives in some of the harshest operating environments imaginable. We are in the process of migrating to a surface mount technology for the LED drive and battery charging circuits as through hole components start to become obsolete.

Operation

Value Chain
SociaLite lighting systems are not free—our overall goal is to become a self-sustaining operation. Whether this is possible is open to question—we have chosen to work with the most marginalized communities on the planet—those who now fall out of the remit of the large philanthropic and UN agencies—the forgotten communities of 2020. How does the financing work? Someone, somewhere has to purchase the equipment and the end-user has to pay the real price—with a subsidized or zero rate of interest. Homer Atkins, in The Ugly American, stated “Whenever you give a man something for nothing the first person he comes to dislike is you.” [W. J. Lederer and E. Burdick (1958), The Ugly American, New York, Norton]. Upon introduction of SociaLite to a community, users pay a deposit (≈ 5USD) on acquisition of a lantern to join the "lighting club", followed by a monthly charging fee (≈ 2USD)—adjusted to match community assets. Extra income is derived from the per use payment for cell phone charging and use of the audiovisual entertainment facilities.

These income streams pay off the capital cost of system components, installation, day to day operation (including lantern battery replacement and recycling) and maintenance—the excess being used to purchase the equipment for succeeding communities.


Accepting the ever growing financial divide, our current model for SociaLite is the provision of a lighting service in which users pay for the use of the lanterns on the understanding that SociaLite Lighting Systems ultimately owns the equipment—this because the community will take a long time to pay off the capital cost of the equipment once the operating costs have been taken into consideration. This of course does not preclude an entrepreneur purchasing a complete system outright—with or without a service/support option.

Without the advantages of bulk purchase, the cost of a lantern is approximately 30USD per lantern (with bulk purchase this approaches 10USD)—allowing compensation for those who assemble, install and operate the system. The cost of PV panels has dropped to <1USD/watt peak for rigid panels and to approximately 1.40USD/watt peak (incl. shipping) for lightweight, flexible CIGS panels from Switzerland; robust lead acid batteries (75Ah) run to about 150USD in country. With audiovisual facilities, the cost of a typical installed mini-grid is approximately 1500USD.

Mini Grid


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Isolated communities comprising more than about 50 households have their own mini-grid with or without the optional audiovisual entertainment system. The mini-grid is capable of simultaneously charging up to 20 lanterns and 8 mobile phones (numbers adjusted to suit community requirements) and powering the home theater.

New in 2020 is the implementation of a mobile charging and entertainment system, a mini-grid on wheels to serve the power needs of smaller communities for whom it is currently uneconomic to install a dedicated system. The first prototype is currently being tested in the Wa West District in the Upper West region of Ghana. In addition lantern and cell phone charging facilities, the new mini grid includes video projection and audio amplification facilities - a pico projector and audio amplifier.

The community members chosen to run the charging station are responsible for collecting the weekly charging fee for the lanterns, the per use fee for charging phones and renting the entertainment system from which they receive a proportion of the income.