Expect a home battery to last 10 to 15 years. The Energy Saving Trust puts the typical lifespan at about 10 to 12 years. Warranties usually promise 70% to 80% of capacity after 10 to 12 years (Enphase: 60% after 15 years or 6,000 cycles), and a field study of 21 home batteries in Germany found an average loss of about 2 to 3 percentage points of usable capacity a year. Batteries then keep working at reduced capacity rather than stopping.
What the warranties actually promise
| Battery | Warranty term | Capacity promised at the end | Throughput limit and conditions |
|---|---|---|---|
| Tesla Powerwall 3 | 10 years | 80% of energy | Unlimited cycles for solar self-consumption, time-based control and backup; other uses capped at 37.8 MWh. Must be bought from Tesla or a certified installer; full term needs an internet connection (otherwise at least 4 years) |
| Enphase IQ Battery 5P | 15 years or 6,000 cycles, whichever first | At least 60% | Continuous internet connection and registration within 45 days |
| Fox ESS EQ and EVO ranges | 12 years | 70% of nominal energy | Up to a throughput cap, e.g. 47.88 MWh for the EVO 10 |
| Fox ESS EP and CQ ranges | 10 years | 70% of nominal energy | Up to a throughput cap, e.g. 19.42 MWh for the EP5 |
| Sunsynk battery range | 10 years (product warranty) | Rated 6,000+ cycles at 80% depth of discharge | Check the model’s warranty document |
| GivEnergy (All in One and batteries) | 12 years on paper | 70% of usable capacity | Given by GivEnergy Ltd, in administration since April 2026; not being honoured |
Two things in that table matter more than the years. First, the capacity figure: a warranty that promises 70% at year 12 tells you the maker expects meaningful fade. Second, the throughput cap: dividing it by the capacity gives the number of full cycles covered. Tesla’s 37.8 MWh cap on 13.5 kWh is about 2,800 full cycles for uses outside its listed ones; Fox ESS’s EP5 cap is about 3,750 and the EVO 10’s about 4,680. At one cycle a day that is 8 to 13 years, so a battery doing a full cycle every day may reach its throughput cap before the calendar term ends.
The GivEnergy row shows the limit of any such promise. The GivEnergy battery page sets out its 12-year terms and what the administration did to them.
How fast batteries really fade
The best public evidence comes from a multi-year study of 21 home storage systems in Germany, published in Nature Energy in 2024. On average they lost about 2 to 3 percentage points of usable capacity a year; lithium iron phosphate systems about 2 points a year, doing roughly 200 full cycles a year. The fastest-fading systems reached 80% of nominal capacity after 5 to 7 years, but most still met their warranties because manufacturers build in reserve capacity. The systems studied were first-generation, and today’s LFP batteries are rated for more cycles.
Laboratory work points the same way. A Sandia-led study found LFP cells lasted far longer than other lithium chemistries, between 2,500 and 9,000 equivalent full cycles to 80% capacity, with higher temperatures and deeper discharges speeding up the fade.
What shortens a battery’s life
- Heat. Batteries age faster when warm. Fox ESS’s warranty only holds within an ambient range of −10°C to 50°C, and Enphase reduces charging below 15°C and above 45°C. A shaded, ventilated spot helps.
- Sitting full. Batteries age in storage as well as in use, and faster at a high state of charge. A battery kept at 100% for backup ages a little quicker than one that cycles.
- Deep discharges. Running a battery to empty every day wears it faster than keeping a reserve. The Energy Saving Trust notes that systems should never let a battery discharge to zero; most stop at a set floor.
- Heavy trading. Using a battery for grid services or arbitrage beyond the warranty’s listed uses can hit a throughput cap sooner, which is why Tesla and GivEnergy set separate fair-use limits for third-party control.
Plan for one replacement, not a failure
A battery at the end of its warranty does not stop; it holds less. A 10 kWh battery at 70% still stores 7 kWh. Which? advises owners to budget for replacing a battery at least once over the life of their solar panels, and the Energy Saving Trust notes the battery will need replacing before the panels do.
No source publishes a UK replacement price. Today’s installed battery-only prices are the nearest guide: Octopus lists about 5 kWh from £3,947 and about 10 kWh from £5,336 at April 2026 prices, before any removal of the old unit. This site’s savings model assumes capacity averages about 90% of new across the first 10 years, fading to about 80%, when it shows a 10-year figure.
A replacement is a new purchase at the prices of the day; today’s installed prices by size are in the solar battery cost guide.
End of life and recycling
A home battery weighs far more than the 4 kg threshold in UK rules, so it counts as an industrial battery. Producers of industrial batteries must take waste ones back free of charge in the circumstances the regulations set out, and it is illegal to send them to landfill or incineration. Ask your installer who will take the old battery away when it is replaced.
What this means when you compare quotes
Compare warranties on three numbers: years, capacity promised and the throughput cap, and check the conditions, such as internet connection or an approved installer. Then check who stands behind the warranty; the GivEnergy administration shows why that matters, and a licensed brand such as Duracell home batteries shows the same question from the other side: the name on the case is not the company that honours the warranty. When you are ready, compare battery storage quotes with the warranty terms written into each one. Home batteries in Cardiff or Bangor carry the same warranties as anywhere else, but the tariff and network differ across Welsh home battery storage, so check the saving as well as the guarantee.
Questions people ask
How many years does a home battery last?
Typically 10 to 15 years. The Energy Saving Trust says about 10 to 12; most warranties run 10 to 12 years and Enphase's IQ Battery 5P is warranted for 15. After that, a battery usually keeps working at reduced capacity rather than failing outright.
How many cycles does a lithium home battery last?
Manufacturers of lithium iron phosphate (LFP) home batteries commonly rate them for about 6,000 cycles (Fox ESS EVO 10, Enphase IQ Battery 5P, Sunsynk's range) and some modules for more than 8,000. At one cycle a day, 6,000 cycles is about 16 years.
Does a battery lose capacity over time?
Yes. A multi-year study of 21 home batteries in Germany, published in Nature Energy in 2024, found an average loss of about 2 to 3 percentage points of usable capacity a year, around 2 points for LFP systems. Heat, high states of charge and deep discharges speed it up.
How much does it cost to replace a home battery?
No source publishes a UK replacement price. The nearest guide is today's installed battery-only price: Octopus lists 5 kWh from £3,947 and 10 kWh from £5,336 at April 2026 prices. Removing and recycling the old unit may be extra.
What happens to a home battery at the end of its life?
A home battery weighs far more than 4 kg, so UK rules treat it as an industrial battery. Producers must take waste industrial batteries back free of charge in the circumstances set out in the regulations, and sending them to landfill or incineration is illegal.