Short answer: for almost all new solar-plus-storage projects, LiFePO4 is the better choice. It lasts far more cycles, delivers more usable capacity per rated kWh, is more efficient and needs no maintenance. Lead-acid has a lower upfront price, but its shorter life and lower usable depth of discharge usually make it more expensive over the system's life. Lead-acid still appears in some very low-budget or legacy off-grid systems.
LiFePO4 vs lead-acid at a glance
| Attribute | LiFePO4 | Lead-Acid |
|---|---|---|
| Cycle life | Thousands of cycles | Hundreds of cycles |
| Usable depth of discharge | High (often ~90%+) | Low (~50%) |
| Round-trip efficiency | High | Lower |
| Maintenance | None | Periodic (flooded types) |
| Weight / size | Lighter, compact | Heavier, bulkier |
| Upfront cost | Higher | Lower |
| Cost over life | Lower | Higher |
Why usable capacity matters
A battery's rated kWh is not the same as what you can use each day. Lead-acid is typically limited to around 50% depth of discharge to protect its life, so a 10 kWh lead-acid bank gives roughly 5 kWh usable. A LiFePO4 battery often allows ~90%+, so a 10 kWh LiFePO4 gives around 9 kWh usable — nearly double the everyday energy from the same nameplate.
Total cost of ownership
Lead-acid looks cheaper on day one, but because it lasts far fewer cycles, it is usually replaced several times over the life of a LiFePO4 battery. When you add up replacements, lost usable capacity and lower efficiency, LiFePO4 typically wins on cost per usable kWh over the system's life.
When lead-acid still makes sense
- Very tight upfront budgets where the buyer accepts a shorter life.
- Small, occasional-use or legacy off-grid systems.
For everything else — homes, businesses and utility projects being built today — LiFePO4 is the default.
COTECH Solar's storage range is entirely LiFePO4, from plug-in balcony kits to liquid-cooled 5 MWh containers. See Energy Storage or ask our team which fits your project.
FAQ
Is LiFePO4 better than lead-acid for solar?
For most projects, yes. LiFePO4 lasts far more cycles, offers more usable capacity per rated kWh, is more efficient and needs no maintenance. Lead-acid is cheaper upfront but usually costs more over the system's life. LiFePO4 is the default for new solar-plus-storage installations.
How much of a LiFePO4 battery can I actually use?
LiFePO4 batteries typically allow a high depth of discharge — often around 90% or more — so most of the rated capacity is available each day. Lead-acid is usually limited to about 50% to protect its life, giving far less usable energy from the same nameplate capacity.
Does LiFePO4 need maintenance?
No. LiFePO4 batteries are sealed and maintenance-free, managed by a built-in battery management system (BMS). Flooded lead-acid batteries, by contrast, may need periodic checks and topping up.