How long does commercial battery storage last?

Battery life is measured in cycles as much as in calendar years. One cycle is a full charge and discharge; a system cycled once a day ages faster in calendar terms than one used lightly. Commercial lithium iron phosphate (LFP) batteries, common in business storage, are typically rated for several thousand cycles before reaching their warranted end-of-life capacity.

How you use the battery matters. Deep daily cycling for peak shaving or solar shifting uses cycles quickly but earns the most value. A battery held mainly for backup cycles rarely and may last longer in years while delivering less saving. The right sizing balances the two.

Lithium batteries do not stop working on a fixed date. Instead their usable capacity declines slowly, so a five-year-old battery stores a little less than when new. Heat, very high charge rates and consistently running a battery from full to empty all speed this up, which is why commercial systems include thermal management and are rarely run to their absolute limits.

Because the fade is gradual, an ageing battery keeps delivering value, just with slightly less headroom each year. Good monitoring shows the trend so you can plan ahead rather than being caught out.

Manufacturers usually warrant a battery to a stated number of cycles or years and a minimum retained capacity, often in the region of 70% at end of warranty. Read whether the warranty is based on throughput (total energy cycled), calendar time, or whichever comes first, as this affects the real-world cover.

Under an outright purchase, replacement is your cost when the time comes. Under a PPA the funding partner owns and maintains the equipment for the roughly 20-year term, so battery upkeep and replacement typically sit with them until the system passes to you for the nominal £1. Confirm the maintenance scope in the agreement.