Battery life is counted in cycles, one full charge and discharge. Divide the cycle count by the cycles you use per year and you get a rough lifespan. A system that cycles its battery once a day uses about 365 cycles a year.
| Battery type | Typical cycles | Years at 365 cycles a year |
|---|---|---|
| LiFePO4 | 3,000–6,000 | 8 to 16 |
| NMC lithium-ion | 1,500–3,000 | 4 to 8 |
| AGM lead-acid | 400–800 | 1 to 2 |
| Gel lead-acid | 500–1,200 | 1.4 to 3 |
| Flooded lead-acid | 500–1,200 | 1.4 to 3 |
These are typical figures, and they assume you stay within the usable depth of discharge in the table on the batteries page. Real life depends on the brand and your conditions, so check the manufacturer's rating.
A lead-acid bank can be cheaper to buy but may need replacing several times in the life of one LiFePO4 bank, so compare the price per cycle, not only the price on the tag.
Next step: size your battery with the battery size guide and the batteries page.
