By pushing the state of the art on LED illumination, Solaris Offgrid was able to design and engineer the most efficient lamp at the most competitive price.
Solaris Offgrid Product Development Services kicked off this first project in 2018. Joining forces with a Paygo Solar Home System (SHS) distributor in Tanzania, our team of engineers conducted a research on efficient LED lighting for solar home systems that would lead us to engineer an efficient and affordable LED shade tailored specifically to the Sub-Saharan Africa users’ requirements.
While most SHS manufacturers focus on the energy management part of the system, lamps are the appliances that imply more user interaction than any other component of an SHS. As such, we took upon the challenge of designing and engineering an improved alternative for SHS LED lighting that offers better efficiency (lumen per watt) and retail price when compared to what the distributor had access to.
In order to understand where their product should stand regarding cost and performance, we started our design process with a market research to set a comparison matrix that would give the foundations of the first prototype. This enabled us to start researching and prototyping the first printed circuit boards (PCB), pushing the boundaries of current LED lamps in the market.
However, not all was plain sailing. When we received the first prototype board and soldered the LEDs on top of the PCB, several of them would not light up. At first, we assumed that the components were not soldered properly, so we resoldered them to the board. Eventually, we would discover that some PCB traces were not calibrated according to the distance that energy travels inside the board, producing significant differences in resistance. After realizing this, we simply focused on modifying the PCB traces and the whole set of lights turned on.
Once the boards were assembled, we carried out multiple in-house tests to assess the performance and have accurate measurements before testing our hardware in the field.
Very quickly, we achieved our goal of 125lm per watt, overperforming on efficiency ratio compared to what the distributor had access to locally. In addition, a first batch of mechanical prototypes was produced to try light diffusion, beam angles and endurance capabilities. These models would serve as a foundation which could give us direct feedback related to usage and lighting preferences.
Now it was time to personally pay a visit to the distributor locally to verify the projections.
Solaris Offgrid engineers testing LED consumption of the first electronic prototype.
We decided to have the full East African experience. Sitting at the back of a Boda-boda bike, the technician and I had to travel hundreds of kilometers, through different villages, just to find SHS clients interested in giving their feedback.
Once in the field, by testing both electronics and hardware, we were able to obtain valuable first-hand data. To our surprise, some preferences, such as light temperature, use function and endurance were much more different than initially expected in the Sub-Saharan Africa scenario when compared to western countries, for instance.
In that respect, I learned that the type of light we choose somehow has a cultural influence. Coming from Latin America and having lived in Europe for some time, I always assumed that we prefer warm lighting because it makes us feel more cozy. Little did I know that, in rural Tanzania, a high percentage of people favour white or cold light, as they value more the amount of lumens emitted than the light temperature. To them, a bright place not only represents a safer place, but it’s also a status symbol. Such details allowed us to have plenty of room for improvement, both on the mechanical and electrical sides of the project.
Back in our office, our team was really enthusiastic to apply the required changes on the PCB. This decision was carefully taken in conjunction with choosing the light diffuser material, as both parts would define the resulting light brightness and temperature.
Stack of light diffuser samples: different texture, thickness and materials tested
On the mechanical side, nearly a complete redesigning had to be made to adapt a single lamp shade to multiple uses. Now the lamp shade would not only be able to hang from the roof, but could also be wall-mounted on rustic walls, given many users had requested the possibility of such configuration to be implemented on the exterior of houses as a “security light”.
For the main build material, we picked slightly polished aluminium, so this rust-proof material would provide us with an easy-to-coat surface and, at the same time, a highly reflective finish on the inside to maximise the light emitted by the sun. Moreover, aluminium proved to be an economic material of premium quality that would enable us to nail the lamp directly to the wall without damaging the lamp shade.
When the time to manufacture arrived, we had already chosen the standard components that would complete the final assembly (BOM). Through direct communication with suppliers located near the assembly line, we acquired the corresponding wires, connectors and switches at the most competitive prices around the globe.
Trying to replicate a lighting testing laboratory, we built a dark room made out of recycled cardboard boxes and tape. We then carved multiple holes at different distances to allocate the light-meter and obtain readings the same way laboratories do. It was amusing for us to see how we could resemble the lab-testing process with so little, but naturally we would later back our claims with certified results.
Once we had all the final components working together, we sent a few samples to a laboratory specialized in measuring lamp brightness, temperature, consumption and other relevant information, matching the results of our frugal dark room with a 95% accuracy.
With certified tests, now our client can properly claim to have one of the "most efficient LED lights in the market" thanks to our team’s determination to engineer a durable and reliable LED lamp with 250lm at 2W of consumption.
Ulysses De Waegemaeker, Industrial Engineer at Solaris Offgrid
About Solaris Offgrid :
Solaris Offgrid supports distributors of essential services to build strong customer traction and greater relations with investors through flexible and inclusive Paygo solutions, designed for last-mile operations. Adopting a bottom up approach in the design of its solutions and creating synergies with a strong network of partners to solve last-mile challenges, the company has already deployed Paygo solutions in more than 30 countries through PaygOps, Solaris Offgrid in-house software solution built “In the Field, for the Field” and its product development services. Leading reference in the off-grid solar market, PaygOps, is engineered to deliver modular and interoperable solutions to address off-grid energy access challenges and distribution complexity. For more information on PaygOps, please contact enquiries@paygops.com.
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