Technology brief
Why we specify LFP over NMC on weak grids
June 2026 · Equator Solar engineering team · 4 min read
Battery specifications are usually compared on capacity, because capacity is the number on the datasheet that everyone recognises. On a weak grid it is close to the least useful number to compare on.
The duty cycle is the real difference
A backup battery in a stable market sits at float for months and discharges a handful of times a year. The same battery on a Ugandan commercial site may be called on several times a week. It is doing the work of a cycling battery while being sold as a standby battery, and it will age like a cycling battery.
That is the frame we specify in. What holds up over time is how many useful cycles the battery will still have in year eight.
Thermal behaviour, in a climate that does not help
Heat ages cells, and a plant room in Kampala is not a temperate basement. Lithium iron phosphate is more thermally stable than nickel manganese cobalt, with a higher onset temperature for thermal runaway and a gentler failure behaviour if it does get there. On a site where the battery lives in a warm room next to production, that margin is worth more than the extra energy density NMC offers.
Energy density is where NMC wins, and in an electric vehicle that is decisive because mass and volume are the binding constraints. In a plant room, floor space is rarely what limits us.
What the specification actually protects
Chemistry alone does not deliver service life. Deep discharge, high temperature and hard cycling all age a battery regardless of what is inside it, so we set a safe charge floor, monitor temperature continuously and configure charging to protect the cells rather than to hit a headline charge time.
The batteries we build with carry a 10-year product and performance warranty and typically last 12 to 15 years in service. Over a 25-year system life, that means planning for one replacement. A specification that ignores duty cycle and thermal exposure turns that single replacement into two, and the second one lands on the client rather than on the warranty.