Battery storage · Guide
How long do solar batteries last?
Most home solar batteries last around 10 to 12 years. That is the Energy Saving Trust’s figure for a typical battery. Panels last 25 years or more, so most systems will need a new battery at some point.
Mon–Fri 9:00am–5:00pm · Clear written quote before any work starts
Talk to us about solar, batteries or repairs.
Call 0800 156 0191, Monday to Friday, 9:00am–5:00pm, or send us a message through our contact page.
MCS certified
NAPIT registered
TrustMark approved
Fully insured
England, Wales & southern Scotland
Ageing
What “worn out” means for a battery.
A battery doesn’t stop on a set date, though. Like a phone battery, it slowly holds less charge as it ages. How quickly that happens depends mostly on heat, how hard it is worked, and how it is set up.
Two things age a battery:
- Cycles. Every time it charges up and runs back down counts towards its life. A battery that does a full cycle every day ages faster than one that is only partly used.
- Time and temperature. Even a lightly used battery slowly loses capacity with age, and heat speeds that up.
Manufacturers publish how much of its original capacity a battery should still hold after a set number of years or cycles. It is on the battery’s datasheet, and it is the best guide to what “worn out” means for your model.
A battery at the end of its useful life usually still works. It just stores less, so it runs out earlier in the evening than it used to.
Wear
What shortens a battery’s life.
- Heat. High temperatures are the main thing that ages lithium-ion batteries. A battery in a hot, unventilated space loses capacity faster.
- Running it flat every day. Repeatedly discharging a battery all the way down wears it faster than keeping some charge in reserve.
- Settings that don’t suit your tariff. A battery set to charge and discharge more than it needs to can rack up extra cycles for little saving.
- Faults elsewhere in the system. A communication fault between the battery and the inverter, a tripped breaker or a failing inverter can make a battery look finished when it isn’t.
Cold is less of a threat to a battery’s lifespan. Many batteries charge more slowly, or pause charging, when they are very cold, to protect themselves.
Warning signs
Signs your battery is wearing out or has a fault.
- It runs out noticeably earlier in the evening than it did a year ago, in similar weather.
- The app shows it never reaching full charge, or its usable capacity (sometimes called “state of health”) falling. See solar battery not charging? for checks to try first.
- It has stopped charging or discharging at all, or keeps dropping offline.
- There are error codes or warning lights on the battery or the inverter.
Keep clear and call an engineer if you notice a hot or burning smell, swelling, hissing, smoke or scorch marks. Follow the emergency shutdown procedure on the label near your inverter only if it is safe to do so. If there is any sign of fire, call 999.
A battery that has stopped altogether hasn’t necessarily reached the end of its life. Get the system tested before you replace anything.
Repair or replace
Repair or replace?
Often fixable:
- communication faults between the battery and the inverter;
- settings or software problems;
- a tripped breaker or isolator;
- on some modular systems, a single failed module or control part.
Usually time to replace:
- a battery that has lost much of its capacity through age;
- a model that is no longer supported and has no spare parts;
- repeated cell faults.
Our engineers test the whole system first, including panels, inverter and battery, so you don’t replace a battery that wasn’t the problem. We work on batteries fitted by any installer, including installers who are no longer trading. You get a clear written quote before any work starts. See battery storage and solar panel repair.
If the battery does need replacing, check what your inverter can work with. On many systems the battery and the inverter have to be compatible, and an older inverter may be near the end of its own life. See how long do solar inverters last? and what a solar battery costs.
Location
Where your battery is makes a difference.
A cool, dry, ventilated space is kinder to a battery than a hot one. The Energy Saving Trust lists garages, external walls and utility rooms as usual places for a home battery.
The current UK standard for fire safety of home batteries, PAS 63100:2024, says batteries shouldn’t be installed in lofts, roof spaces or voids, in rooms used for sleeping, or on escape routes such as hallways, landings and stairs. If an older battery is in one of these places, ask for it to be checked. See can solar panels catch fire?
Looking after it
How to help your battery last longer.
- Keep its vents clear. Don’t store boxes against it or cover it.
- Leave the minimum charge setting at the level the installer or manufacturer recommends.
- Keep it connected to the app and your Wi-Fi, so faults show up.
- Match charging to your tariff and the season. In winter, charging overnight on a time-of-use tariff can make sense. In summer the panels should do most of the work. See do solar panels work in winter?
- Have it checked on the yearly service. See solar panel maintenance.
Sources: Energy Saving Trust, Battery storage (updated August 2026); pv magazine, How long do residential solar batteries last?; BSI PAS 63100:2024.
Our Solar Maintenance Plans include a check of your battery system on every yearly visit, with each report kept in your My Solar account.
Questions
The things people ask before they ring.
Not answered here? Call 0800 156 0191, Monday to Friday, 9:00am–5:00pm.
How long do solar batteries last?
Most last around 10 to 12 years, according to the Energy Saving Trust. They don’t stop suddenly; they gradually hold less charge. Heat, running flat every day and poor settings shorten that. A cool location and sensible settings help.
Do solar batteries lose capacity over time?
Yes. Every battery holds a little less each year. The manufacturer’s datasheet shows how much capacity it should keep after a set number of years or cycles.
Is it worth replacing a solar battery?
Often, yes, if your panels and inverter are in good order and you use most of your stored power in the evening. Get the system tested first. A battery that has stopped can have a fault elsewhere, such as a communication problem with the inverter.
Will you repair a battery another company installed?
Yes. We repair and replace batteries on systems fitted by any installer, including installers who are no longer trading, across England, Wales and southern Scotland.
Ready when you are
Battery not lasting like it used to?
We’ll call you back to talk it through, and you get a clear written quote before any work starts. Mon–Fri 9:00am–5:00pm.