Lead-acid batteries still work. They are just no longer the right answer for most new solar projects in Africa. Three years ago, the math was different. Today, with lithium cell prices at a third of their 2022 level, the total cost of ownership tips the other way.
The cycle life gap is the killer. A good tubular lead-acid battery gives you 1,200 to 1,500 cycles at 50 percent depth of discharge. A LiFePO4 cell gives you 4,000 to 6,000 cycles at 80 percent depth of discharge. In a daily-cycle solar setup, that is roughly 4 years for lead-acid and 10 to 12 years for lithium, with usable capacity staying flat on the lithium side and degrading on the lead-acid side.
Depth of discharge matters. Lead-acid really does not like going below 50 percent. Doing so every day cuts its life in half. LiFePO4 is comfortable at 80 percent and survives 100 percent without damage. So a 10 kWh LiFePO4 battery gives you 8 kWh usable, while a 10 kWh lead-acid bank gives you 5 kWh usable for the same cycle life.
Weight is the other surprise. A 10 kWh LiFePO4 battery weighs about 100 kg. The equivalent lead-acid bank weighs 280 kg. For rooftop installs in markets where labour is expensive, that is real money saved on mounting.
Where lead-acid still wins: very cost-sensitive buyers with infrequent use, telecom backup that sits at float most of the time, and any case where the buyer cannot afford the upfront cost. We still ship lead-acid for a few specific buyers. For daily-cycling solar, lithium is the answer now.