The Battery Factory of Kirolo
Africa Annals #5
On the morning of Thursday April 30th, I woke up early, checked out of my Airbnb at 6:30 AM, and crossed Kampala by taxi to a make rendezvous at 7 AM. I was meeting Brendan Cronin, CEO of Soleil Power, a new battery-focused “sister company” of leading frontier-market solar installer Aptech Africa. Both are now part of the new umbrella company Massawa Group, a fast-growing superstar of African electrotech deployment. I had interviewed Aptech CEO and co-founder Metkel Abraham over a video call in 2025, and I’d been absolutely fascinated by their bold and heroic endeavors to bring a clean first-ever electricity source to some of the most dangerous places in the world.
After several days of coordination efforts over WhatsApp, I received a kind offer for Brendan to drive me from Kampala to the new Soleil Power battery factory in Kirolo, a village about an hour to the north. He picked me up at the rendezvous point in a black Toyota Land Cruiser, and we drove off. Brendan had some fascinating stories to tell. An American originally from Maryland who’d worked as a Caribbean boat captain before getting a mechanical engineering degree, he’d been working in equatorial African infrastructure and development for the last twenty years in various roles across Gabon, Congo-Brazzaville, South Sudan (just before the civil war) and now Uganda. Along the way, as we traversed an uneven medley of recently paved stretches breaking up eroded red dirt roads, Brendan told me how he’d come to this position. Soleil Power itself was a brand new company, a battery startup budding off Aptech’s highly successful solar-focused business. It had started existence around 2021, and Brendan had been hired as CEO in 2022, excited for a new challenge. Soleil started with prototypes in a tiny workshop in Kampala, and after years of work moved to a new purpose-built factory space on a plot of land they’d bought near Kirolo, with operations there beginning in July 2025. This new factory was the first multi-use1 lithium-ion battery assembly plant anywhere between South Africa and the Sahara.
We eventually arrived at a big gray building on a rural unpaved lot. A solar-powered borehole well on the left of the building provided drinking water. This was the new factory — we were here! It was already in operation but also still under construction itself, with new machinery and component materials arriving in shipping containers after traversing the Indian Ocean to the Kenyan port of Mombasa and then crossing overland on a truck to drop stuff off right at the doorstep. As Brendan and I walked in, I could see a production line taking up one wall on the left and a range of other tech spaced out across the other walls. It was just past 8 AM, and the employees had arrived just before we did. Brendan told me that what they had now amounted to a three fully functional semi-automated early production lines, one for metal casing fabrication and two co-located battery production lines assembling modules from both cylindrical cells and prismatic cells. As workers gained skills and experience in battery-making, they were planning to soon upgrade to fully automated assembly lines to speed up the process. EV motorbike companies had been the first to hire people to work on batteries in Uganda, but Soleil was the first to build diversified lithium-ion and lithium-iron-phosphate (LFP) batteries for home, business, and EV uses, and they were regularly hiring and training workers with no previous battery experience — growing the whole sector.
It was a hot, sunny day outside when we arrived, though there had been rain earlier and it would rain more later in the day. Nevertheless, the space inside the factory was cool and shady, notably more comfortable than outside despite all the machines running. Soleil now had 20 full-time employees, and was still receiving substantial logistical support from the much larger Aptech. The working language was English, a common ground spoken by skilled Ugandan employees from a range of cultural backgrounds. Brendan told me that they hired many of their employees from Kampala universities based on electrical experience, but were also hiring some part-time “casual” workers from the local Kirolo village community with the goal of moving them to full-time as they gained skills and practice.
Like everyone else in Africa, Soleil imports part of their electrotech from China. But where they differ is that they only important the most basic sub-component of a battery: pallets of raw cells, single small cylinders or rectangles that chemically store energy. At the factory, they assemble these basic cells into functional productions, adding grounding, insulation, and connector cables around multiple cells connected as a module, then arranging them into full multi-module battery packs of different form factors and power output levels suitable for different use cases.
Brendan gave me the tour of the major pieces of equipment. There was a CNC laser cutter, a compressor-fed press-fit machine, and a drill press, all for machining the custom metal superstructure of the battery packs that held the modules in alignment.
There was a powder coating booth for painting those metal parts. There was a huge inventory zone, full of pallets of battery cells and soon-to-be-assembled new equipment.
There was a machine for stamping terminal sections on the positive and negative ends of the raw lithium-ion and lithium-iron-phosphate battery cells.
And interspersed with the semi-manual production line, there were a wide range of different battery testing devices for different stages of the process. Brendan proudly described their high process control to ensure consistent quality. This Soleil factory had already won several international certifications, including ISO 9001:2015 for quality management, ISO 14001:2015 for environmental management, and ISO 45001:2018 for occupational health and safety.
Checking the functionality of battery cells before using them, checking the functionality of cells assembled into modules, and checking the functionality of full ready-to-go battery packs.
As of right now, after less than a year, Brendan told me that this Soleil factory has a production capacity of 10,000 to 20,000 battery pack units, with unit size ranging from 1 to 5 kilowatt-hours of storage. (These battery pack units themselves can be grouped together in racks of sixteen or thirty-two for larger-scale uses, like for a business instead of a home).
In addition to the wide range of machines forming part of the battery pack assembly process, there were also electric motorcycles parked in several different corners around the factory. All were bikes from Ugandan e-mobility company Zembo, part of the Soleil company fleet as well as factory testing platforms for using Soleil batteries in two-wheeler EVs.
After two years of R&D and testing, Soleil has begun to commercially supply battery packs Zembo for use in their bikes and swap stations. Soleil’s marketing efforts have only just begun, but they’ve already built relationships with early customers.
Another relevance of motorcycles to this factory was as a source of new input components. Brendan told me that in addition to importing fresh battery cells from China to assemble into packs, they were also “triaging” battery cells from the fast-growing African e-mobility sector (all those electric motorbikes). Some of the time, some cells from bikes that had reached the end of their useful life could still be reconfigured for a second “upcycled” life in a battery pack. Testing was especially important to sort these ones out. Soleil was a pioneer in this emerging circular economy of energy storage, the very first company to go to market in Uganda with a second-life lithium-iron-phosphate battery product like this.
The tour finished, Brendan moved on to the many pressing tasks that did not include providing live narration and guiding for a curious Substacker. After checking that it wouldn’t be too much of a disturbance, I walked backwards up the production line, starting with the most finished product, and conducted a brief interview with each Soleil employee I met along the way.
First, I talked with Berna, an outgoing woman analyzing data at a computer console. She was the Assembly Lead, a role of great responsibility as the manager essentially running this entire factory day-to-day when more senior personnel were elsewhere. She’d been working with Soleil since April 2025, and was a big fan of renewable energy and particularly battery storage.
Reagan was using a TFT (thin-film transistor) diagnostic machine to triple-check the performance of a nearly complete battery pack. He’d been working here for two years, since 2024, and said it was because he liked renewable energy.
Daniel was one of the part-time workers hired from the local community, and was working on adding connector cables to a mostly-finished battery pack. He told me precisely that he’d been with Soleil for seven months and sixteen days, and that it was a good job.
Next up was Mukisa, another “casual” local part-timer, attaching metal casings to the newly cabled and insulated battery cell packs. He said he was on his third month and loved working with this team.
At the center of the production line, Shakirah was adding cables and insulation to a battery recently assembled from a network of cells. She’d been working with Soleil for one year, and told me she’d come to learn more and grow her career.
At the step just before, Lilian was adding nickel strips to help hold the battery cells in place as a pack. She said she’d been working here for one year, and took the job because it was “unique.”
Hafiswa was doing quality control, checking QC data for battery cells on a laptop just in front of the testing machines. She told me she’d been working here for nine months, and that she’d joined because she was really interested in batteries and wanted to learn more.
Then, at the far end of the production line, I met Abu and Marvin, working together on two laptops open to SolidWorks CAD and Excel respectively. They were designing a new prototype battery pack form factor, working towards a more “stackable” model that could click together without needing an external frame. Both were veteran Soleil employees: Abu had worked here for two years and Marvin one and a half. They both also said that they were working here because they loved clean energy.
Beyond them, the only other folks working in the factory when I was there were Vincent and Isa, both at work on the other side of the building from the main production line powder-coating metal battery pack parts with black paint. Vincent said he loved working here, and had done so for two years.
After that, as Brendan moved around the factory discussing various details, I walked around by myself, took some more pictures, and eventually fell into conversation with Berna again. I asked her if she wanted to share any message with future readers from around the world, and she said “Love from Africa!” We talked more, and she animatedly shared her ambitions for renewable energy to help power Uganda’s development. “Green energy is happening globally and to us here in Africa. Battery storage is really important because it works across all electricity sources. We can fast-forward through the process you guys [foreigners, Westerners] went through. We can learn from what you guys did. We can have a future where we’re more like you guys, a mixed country where people from all over feel they can come.” I was humbled and inspired by her enthusiasm.
As we stepped outside to head back to Kampala, Brendan outlined potential future plans for Soleil Power. Once they filled up this factory with new semi-automated assembly lines, they could build another one right next to it on the same multi-acre plot of land. They could pave the access road and parking lot, although that would be so expensive it wasn’t a near-term priority. They might even build on-site employee housing. There was lots of room to grow, and a strategy to make it happen. In Uganda, Soleil wasn’t planning to compete on price with the multiple straight-outta-China all-imports solar installers (including current local sales volume leader Felicity Solar, which I’d seen in the Kampala streets), but they could compete on being customizable, flexible, extra-reliable, and more reactive to the needs of the local market. A battery from China might linger in various importers’ inventories for a year by the time it’s sold at local distributors in Uganda, and it would be made to one of a set few preexisting models designed and built in China for global markets which might or might not match what people in Uganda wanted just then. Soleil could build small batches of uniquely formatted battery packs with custom sizes, shapes, and power outputs to meet individual local business clients’ specific needs as they arose. After ten years of scaling up their factory and their home, business, and EV batteries, Soleil could be building grid-scale battery packs the size of a shipping container. I don’t know what the future holds for this company, but I do know that they’ll be doing their darnedest to seize the day and help build a cleaner future for Africa.
It was a pleasure and privilege to visit this brand-new outpost of the electrotech revolution, with a dedicated team building an unprecedented center of clean industry in Africa. Spectacular work!
This qualifier excludes the electric motorbike companies’ product-specific in-house repair shops: Soleil is assembling lithium-ion and lithium-iron-phosphate battery packs for multiple uses, something no other factory in sub-Saharan Africa outside South Africa is doing so far!
Exciting, informative reporting and photojournalism again; definitely loved the staff interview piece as well.
I thought it was interesting that you said they weren't planning to compete on price but rather on adaptability and flexibility. I wonder whether there is a market in Africa for "made in Africa," even if it's comes at a slightly higher price. Like the idea that "made in America" products can command higher prices in the US, marketing to a niche that values homegrown. What do you think about that?