Home battery lifespan: how long does a home battery last?
A home battery lasts 10 to 15 years or 6,000 to 10,000 charge cycles. After that it usually still works, just with less storage than when it was new. How quickly your home battery reaches that point is partly in your own hands.
How do you measure a home battery's lifespan?
You measure a home battery's lifespan in three ways: in charge cycles, in calendar years, and in the total amount of energy that passes through the battery. Manufacturers of a home battery usually list a number of cycles and an expected service life in years. Whichever limit is reached first marks the end of the lifespan.
Charge cycles of a home battery
A home battery's charge cycles count how often the battery has been fully charged and discharged again. A cycle doesn't have to happen all at once: going from half to full and back twice adds up to one full cycle. Manufacturers also tie the number of cycles to a remaining capacity.
Anker SOLIX, for example, lists 6,000 cycles to 70 percent and 5,000 cycles to 80 percent for one of its Solarbank models, so only compare cycles at the same remaining capacity.
Calendar aging of a home battery
Calendar aging of a home battery is the wear that occurs even when the battery is barely used. The chemistry in the cells slowly changes over time, which means a home battery that goes through few cycles still has a finite lifespan in years. How fast that aging happens depends mainly on temperature and state of charge, and those are two things you can influence yourself.
Energy throughput of a home battery
The energy throughput of a home battery is the total amount of kWh the battery stores and releases over its lifetime. You can estimate that figure by multiplying the number of cycles by the capacity: a 2.4 kWh battery with 6,000 cycles handles roughly 14,400 kWh. Some manufacturers guarantee their remaining capacity based on that throughput rather than on years.
When is a home battery's lifespan over?
A home battery's lifespan is over once its capacity has dropped to the limit the manufacturer treats as the end of life, usually 70 or 80 percent of the original storage. The battery doesn't stop working at that point, but it stores less: a 7 kWh system still has 4.9 kWh left at 70 percent. For a household with low evening consumption, that can be plenty for years to come.
Capacity loss doesn't follow a straight line. A battery loses relatively more capacity in the first thousand cycles than later in its life, after which the decline levels off. The capacity that remains is called the State of Health (SoH). Check in your system's app whether that value is shown, so you can track the ageing over the years.
How many years does a home battery with 6,000 charge cycles last?
A home battery with 6,000 charge cycles lasts a good 16 years at one full cycle per day, if you only look at the cycles. One cycle per day is a realistic upper limit for self-consumption: the battery charges during the day with solar power and discharges in the evening and at night. In winter the battery reaches a full charge less often, so over a full year you make fewer complete cycles.
If you charge and discharge twice a day, for example because you have a dynamic energy contract and trade on hourly prices, that term is halved to a good 8 years. Both outcomes are a theoretical maximum based on cycles. Calendar ageing comes on top of that.
What determines how long a home battery lasts?
How long a home battery lasts is largely up to you, with four factors: the number of cycles per day, the charge limits, the temperature, and the capacity relative to your usage. You choose the capacity when you buy; the other three you manage during use.
Number of charge cycles per day
The number of charge cycles per day weighs heavily, because every full cycle uses up a small part of the capacity. If you use the battery intensively to earn it back faster, you also use up the cycles faster. So make a deliberate choice: let the battery store only solar power, or also trade on hourly prices, and only do the latter if the extra return outweighs the shorter lifespan.
Charge limits for your home battery
Charge limits for your home battery set the minimum and maximum between which the battery charges and discharges. A battery that sits at 100 percent for long periods or keeps running completely empty ages faster than a battery that operates within a middle range. The battery management system (BMS) already prevents the cells from getting too full or too empty. On top of that, check in the app whether you can set an upper and lower limit yourself.
Temperature around the home battery
The temperature around the home battery affects its lifespan, because heat speeds up the chemical aging in the cells. Above 35 °C, that aging gets noticeably faster, especially if the battery is also fully charged at the time.
A spot that heats up a lot in summer, like an attic right under the roof tiles or a façade in full sun, therefore shortens the lifespan. You can read how to keep the battery cool and what it does in freezing weather in our blog on home battery maintenance.
A capacity that matches your consumption
A capacity that matches your consumption spares the battery, because a home battery that's too small fully charges and discharges every single day. A more generously sized battery runs completely empty less often and makes fewer full cycles per year.
Going way too big doesn't make sense either, because capacity you don't use doesn't pay off. You can read how to determine the right size in our buying guide on which home battery you need.
Which home battery lasts the longest?
The home battery that lasts the longest has cells made of lithium iron phosphate (LFP or LiFePO4). LFP is a form of lithium-ion, just like NMC (nickel-manganese-cobalt), but it handles deep cycles better and generally ages more slowly. NMC stores more energy per kilo and is therefore mainly found in applications where weight matters, such as electric cars.
The home batteries from Zendure and Anker SOLIX use LFP cells. For the current models, the manufacturers and independent testers report these values:
- Zendure SolarFlow 3000 Mix AC+, 4000 Mix AC+ and 4000 Mix Pro: 10,000 charge cycles down to 70 percent SoH and a lifespan of 15 years.
- Anker SOLIX Solarbank Max AC and Solarbank 4 E5000 Pro: 10,000 charge cycles and a lifespan of around 15 years.
- Zendure SolarFlow 2400 AC+: 6,000 charge cycles and a lifespan of 15 years according to Test-Aankoop.
For the Mix series, Zendure assumes two full cycles per day, which works out to a lifespan of around 15 years. If you also want the battery to trade on hourly prices, go for a model with 10,000 cycles. For self-consumption only, that number isn't necessary.
Does the warranty match the lifespan of a home battery?
No, the warranty is not the same as the lifespan of a home battery: the warranty is a minimum the manufacturer promises, while the lifespan is how long the battery remains usable in practice. Zendure gives a 10-year manufacturer's warranty on the SolarFlow Mix series and the SolarFlow 2400 AC+ among others, and Anker SOLIX does the same on the Solarbank Max AC and the Solarbank 4 E5000 Pro.
That warranty is shorter than the service life both manufacturers specify. A manufacturer's warranty also often ends as soon as the first of several limits is reached, such as the number of years, cycles or the energy throughput.
You can read which other conditions apply and what to do if the capacity drops sooner in our blog about the warranty on a home battery.
What do you do with a worn-out home battery?
With a worn-out home battery you have three options: keep using it, expand it or replace it. Which choice makes sense depends on how much storage you need compared to what the battery still delivers.
- Keep using: a battery with less capacity still covers part of your evening usage and continues to save you money.
- Expand: with a modular home battery you add extra battery modules to make up for the lost capacity. Check with the manufacturer whether a new module works together with your older modules.
- Replace: if you really need the original storage capacity, you can replace the battery modules or the entire system.
A discarded home battery doesn't belong with your regular household waste. To return it, contact the seller or the manufacturer, because the European Batteries Regulation has tightened the rules for collecting and recycling batteries.
Choosing a home battery with a long lifespan
Choosing a home battery with a long lifespan starts with your own energy usage and the way you want to use the battery. At TechPunt you'll find plug-and-play home batteries from Zendure and Anker SOLIX, shipped from our own warehouse in Barneveld and with a 2-year warranty on every product. Not sure which system will last longest in your situation? Ask our customer service your question by phone, email or WhatsApp.
