Koolboks stored cold as ice, then sold it at $10 a month

Koolboks started in Paris in 2018, founded by pharmacist Ayoola Dominic and Deborah Gael, selling outdoor camping refrigerators to Europeans. The pivot came in 2020: the same off-grid cooling technology mattered far more to African vendors who lose up to 40 percent of their food to spoilage before it reaches market, in countries where grid power is erratic and diesel generators are expensive. Koolboks refocused on off-grid small businesses, starting in Nigeria.

The hardware makes two unusual choices. Instead of a lithium battery bank, the freezers store energy as cold: water inside freezes when solar power is abundant and keeps the cabinet cold for up to four days without power. And each unit is a refrigerator, freezer and light source at once — two LED bulbs plus USB phone charging — in sizes from 110 to 1,000 liters. In 2022 the company raised a $2.5 million seed round led by Aruwa Capital with Acumen, PG Impact, All On and GSMA, bringing total funding to $3.5 million.

Distribution is the other half of the invention. Units are sold on pay-as-you-go contracts of roughly $10–20 a month, paid by mobile phone or through a local POS agent; the customer enters tokens as codes into the fridge to unlock another period of use — the airtime model applied to cold storage. By 2025 the approach had reached over 10,000 users in 25 countries, from market traders and frozen-food vendors to rural clinics, and Koolboks closed an $11 million Series A led by KawiSafi Ventures with All On and Aruwa Capital, funding its first local assembly plant in Nigeria.

Bank cold in water, not lithium; charge like airtime

Batteries are the most expensive, shortest-lived part of a solar fridge; storing energy as ice replaces them with water.

Four days of cold reserve rides out the grid outages that define unreliable-power markets.

$10–20 monthly installments match the cash flow of market vendors who could never buy a freezer outright.

Payment via mobile money and POS agents uses rails customers already trust, and token codes enforce the contract without repossession.

In an unreliable-grid market the cheapest battery is ice. And hardware that saves money still needs money collection that matches the buyer's cash rhythm: small, phone-based installments.

The Series A is scaling production: All On's follow-on investment supported Koolboks' first Nigerian assembly plant, which the company expects to create local jobs and cut costs for end users. The customer base now spans market women, frozen-food vendors and rural clinics across 25 countries, running cold storage without diesel or a stable grid. Koolboks positions itself as productive-use energy infrastructure — appliances that generate income for their owners — rather than a consumer gadget business.