Last reviewed: 6 September 2026. Explains what determines a domestic
battery’s working life and how to read the numbers manufacturers publish. We do not quote lifetimes for
named products, because we have not tested any and manufacturer figures are measured under conditions
that do not match a British utility room.
“How long will it last” is really three questions wearing one coat: how long before it stores
noticeably less than it did, how long before it stops working altogether, and how long the promise
attached to it is worth anything. Most buyers ask the first, are sold on the third, and are eventually
undone by the second.
The four numbers that define a battery’s life
| Figure | What it means | What it does not tell you |
|---|---|---|
| Cycle count | How many full charge-and-discharge cycles before the stated end-of-life condition |
How many cycles a year your household will actually do |
| Throughput (often in MWh) | Total energy that may pass through the battery over its life |
Nothing about calendar ageing, which continues whether you cycle it or not |
| Calendar years | A time limit on the warranty, typically ten | Whether the company will exist to honour it |
| End-of-life state of health | The capacity floor the manufacturer guarantees at the end — commonly a figure between 60% and 80% of original |
That the battery is finished at that point; it usually is not, it is just no longer guaranteed |
The warranty ends when the first of these is reached, and that detail is where most
disappointment lives. A ten-year, 10,000-cycle warranty is not a ten-year warranty if your usage burns
through the cycles in seven, and it is not a 10,000-cycle warranty if you only manage 400 a year.
How many cycles a British household actually does
A domestic battery charging once a day does roughly 365 cycles a year. Two mechanisms drive that
count, and they behave very differently:
- Solar self-consumption: strongly seasonal. In a British winter a solar-charged
battery may go days barely cycling at all, so the annual count falls well short of 365. - Tariff arbitrage: charging cheaply overnight and discharging at peak, every day,
all year. That is close to a full cycle a day and can be more than one if the tariff has two cheap
windows. It is the pattern that consumes warranty fastest — the trade-off examined in charging a home battery on a cheap night
tariff.
This is why a battery bought purely for arbitrage should be assessed against its throughput figure,
not its year count. Cycling hard is exactly what makes it pay and exactly what wears it out; the
economics have to survive both facts at once, which is what our battery payback calculator is for.
Degradation is not a cliff
Lithium batteries lose capacity gradually and then keep working. A unit at 70% of its original
capacity has not failed; it stores 70% of what it used to, which for many households is still enough to
cover the evening peak. Nothing switches off at the warranty boundary, and no manufacturer is claiming
it does.
The practical consequence for buying: size the battery for what you need at end of life, not
at day one, if the difference matters to you. The method is in what size home battery do I need and the battery size calculator. And do not let the payback arithmetic
lean on year nine: if the numbers only work with a decade of undiminished performance, they do not
work.
What actually shortens a battery’s life
| Factor | Effect | Your control |
|---|---|---|
| Temperature, especially sustained heat | Accelerates calendar ageing; sustained cold can restrict charging |
High — it is decided by where you put it: where can a home battery be installed |
| Cycle depth and frequency | More energy through the cells, faster wear | Partial — it is the point of the purchase |
| Sitting at 100% charge for long periods | Higher stress on the cells | Some, through scheduling |
| Chemistry | LFP generally tolerates more cycles than NMC; NMC is denser | At purchase only: LFP vs NMC |
| Charge and discharge rate | Harder use, more heat, more wear | Low — set by system design |
| Firmware and battery management | Protects the cells; also the part that stops being updated if the brand disappears |
None after purchase |
The limit nobody prices: the company
A ten-year warranty is an unsecured promise from a corporate balance sheet, and British owners have
just had a demonstration of what that is worth. GivEnergy Ltd entered administration on 9 April
2026 in the High Court at Leeds and ceased trading; the administrator’s position was that
hardware warranties would not be honoured and software support would not continue, and that consumers
should approach their installer.
The batteries kept working, because cell management and safety protections run on hardware inside the
unit rather than in a data centre. What was lost was the warranty, the firmware updates and the future
of the app. So the realistic answer to “how long will it last” has a fourth component: the hardware may
run for fifteen years, and the promise attached to it may run for four.
Two defences, both cheap. Put at least the deposit on a credit card, because section 75 of the
Consumer Credit Act 1974 makes the card issuer jointly liable for the full purchase price — see section 75 claims. And prefer systems with
open local control, so that losing the cloud does not cost you the scheduling that made the battery pay.
The whole playbook is in what to do if your
battery brand goes bust.
Making a battery last
- Install it somewhere thermally stable — not a sun-facing wall, not an uninsulated loft.
- Avoid leaving it parked at full charge for days on end where scheduling allows.
- Do not chase the last kilowatt-hour: a reserve set slightly above the minimum costs little and
reduces deep cycling. - Keep the ventilation clearances the installer left, and do not build a cupboard around it.
- Record capacity annually — the same charge cycle measured each January — so you have
evidence if a warranty claim ever matters. - Keep the full document pack: invoice, warranty, commissioning certificate, G98 or G99
notification, and how you paid.
Frequently asked questions
Is ten years a realistic life?
For the hardware, in a temperate indoor location and with ordinary domestic cycling, ten years is a
reasonable planning assumption and the industry norm. What is not realistic is assuming full original
capacity throughout, or assuming that a warranty covering year nine will be claimable in year nine.
Does the battery degrade if I do not use it?
Yes. Calendar ageing continues regardless of cycling, which is why leaving a battery idle to preserve
it is a poor strategy: you get the ageing without the savings.
Can individual modules be replaced?
Sometimes, on modular systems, and only while modules are still made. It is a question worth asking
before you buy, alongside how to read a battery
warranty.
What happens at the end?
Domestic batteries fall under the UK’s waste electrical and battery regulations, and disposal goes
through the installer or an authorised recycler, never a skip. Budget for removal costs rather than
assuming a residual value.
Sources.
Consumer Credit Act 1974, section 75 ·
HMRC VAT Notice 708/6 for the VAT position on batteries.
GivEnergy details are as recorded at the time of the April 2026 administration. Degradation factors are
our assessment, not manufacturer data — see editorial
methodology.