I've only visited one place in Africa (Nairobi) an only once (about a decade ago); the cars I saw were all in poor condition and about 20-30 years old when I saw them.
Also one of the people we visited had an income so low their annual rent was equivalent to about US$1k, so consider how old and decrepit a vehicle has to be on a western market to be in her price range.
There's a huge variation of culture and living standards across the continent, from people much richer than that who buy new cars that are expensive by western standards to people who walk miles to get water from a well because there isn't any plumbing.
PV and storage have the advantage of being scalable down to small cheap things that even the poorest can benefit from. Cars, not so much, so for low priced transportation, think instead about e-bicycles and e-motorbikes, and even manual bicycles. Or public transport (but even then, the crowded matatu I was in for one trip looked old).
