SETH ONYANGO, BIRD STORY AGENCY  A bulb, a charging port, a solar panel and a small fee paid via mobile phone are making all the difference as millions of African households dump kerosene and other dirty fuels to light their homes. Off-grid solar finance companies known with pay-as-you-go (or, PAYGo) solutions are even striking a chord with urban consumers looking to cut energy costs and upgrade their home appliances. The PAYGo business model enables low-income customers to finance not only home solar systems but also other related appliances, without collateral. Appliances offered by solar PAYgo providers include solar-powered TVs, radios,…