Solar
Solar Batteries in Kenya: Lithium (LFP) vs Lead-Acid and Gel
Short answer
Lithium iron phosphate (LFP) batteries cost more up front but last several times longer, let you use more of their capacity and need almost no maintenance, so they usually cost less per year of use. Lead-acid and gel batteries are cheaper to buy but typically last about three to five years and should not be discharged deeply.
The main differences
| Lithium iron phosphate (LFP) | Lead-acid / gel / AGM | |
|---|---|---|
| Typical life | 10 years or more; thousands of cycles | About 3 to 5 years; hundreds of cycles |
| Usable capacity | Around 80 to 90%+ | About 50% recommended |
| Upfront cost | Higher | Lower |
| Maintenance | Very little | Flooded types need topping up; all need checking |
| Weight and size | Lighter and compact | Heavy and bulky |
| Charging | Fast, efficient | Slower, less efficient |
Typical figures. Check the datasheet and warranty of the specific battery.
Why usable capacity matters
A 10 kWh lead-acid bank should only be discharged to about 50%, so you can use about 5 kWh. A 10 kWh LFP battery gives you 8 to 9 kWh. Comparing batteries by nominal kWh without usable capacity makes lead-acid look cheaper than it is.
Cost over time
If a lead-acid bank is replaced every four years and an LFP battery lasts ten or more, the lead-acid option may cost as much or more over ten years, plus replacement labour. LFP typically costs less per kWh actually delivered over its life.
What else to check
- Battery management system (BMS): LFP batteries need a good BMS for protection and balancing.
- Inverter compatibility: The inverter must support the battery voltage and communication.
- Warranty: Look for years and cycles, and what the warranty requires (depth of discharge, temperature).
- Voltage: Most home systems use 48 V. Higher voltage means lower current and thinner cable.
- Do not mix: Never mix old and new batteries or different types in one bank.
Which should you buy
For a home or business you plan to keep for years, LFP is usually the better choice. For a very small, low-budget or temporary system, gel or AGM can be reasonable if you accept shorter life and size the bank generously.
Common questions
How long do solar batteries last?
Lead-acid types typically last about three to five years. LFP lithium batteries are commonly designed for ten years or more, depending on use and warranty.
Can I use a car battery for solar?
Starter car batteries are not designed for deep daily cycling and wear out quickly. Use deep-cycle or lithium batteries.
How much battery do I need?
Size it from your night-time load and how many hours of outage backup you want. See our <a href="/blog/what-size-solar-system-for-my-house/">sizing guide</a>.