Published 24/11/2025 · Updated 28/09/2026 · By Voldt® product team
EV battery degradation is the gradual loss of capacity as a battery ages and cycles. Across 22 700 electric cars the average loss is 2,3% a year, so most batteries keep around 80% after eight years. Your charging habits and where you park move that figure up or down.
81,6%
left after 8 years at the average rate
Five beliefs about battery wear, checked against the data
Belief
Fast charging ruins the battery.
What the data shows
Relying on rapid chargers for most sessions roughly doubles the yearly loss, to about 3,0%. Using them for stops on long journeys is fine.
Belief
Never charge above 80%.
What the data shows
That holds for NMC and NCA batteries left full for days. LFP batteries need 100% at least once a week.
Belief
Cold weather damages the battery.
What the data shows
Cold cuts range and charging speed only while it lasts. Heat does leave a mark: about 0,4% a year of extra loss in hot climates.
Belief
After a few years the battery is worn out.
What the data shows
The average loss is 2,3% a year, and the Euro 7 rules the UK has proposed adopting would require new car types to keep 72% at eight years.
Belief
A better cable protects the battery.
What the data shows
The car's own systems set the current, whichever cable is plugged in. A cable's job is to make AC charging possible.
01 · Capacity
How fast does an EV battery lose capacity?
On average 2,3% a year, so a typical battery keeps about 80% of its capacity after eight years.
A battery ages in two ways at once. Calendar ageing happens whether you drive or not, as slow side reactions use up lithium in the cells, faster when they are warm or full. Cycle ageing comes from charging and discharging and grows with the power involved. Together they set the state of health: the capacity left compared with new.
Across 22 700 electric vehicles and 21 models, Geotab measured an average loss of 2,3% a year (Geotab EV battery health study, January 2026). A legal floor is on its way too: in the EU, new car types approved from 29 November 2026 must keep 80% of their battery energy for five years or about 62 000 miles, and 72% up to eight years or about 100 000 miles (Regulation (EU) 2024/1257, Euro 7). The Department for Transport has proposed the same minimums for Great Britain (consultation, April 2026).
Fig. 1
Capacity left after each year of use, at 2,3% a year
100%
Year 0
97,7%
Year 1
95,4%
Year 2
93,1%
Year 3
90,8%
Year 4
88,5%
Year 5
86,2%
Year 6
83,9%
Year 7
81,6%
Year 8
Red line: the Euro 7 minimum for new car types in the EU, proposed for Great Britain. Geotab average, January 2026, as a straight line.
02 · Charging habits
Which charging habits wear the battery fastest?
Frequent rapid charging: cars that relied on it above 100 kW lost up to 3,0% a year, twice the 1,5% of cars charged mostly on AC.
High charging power heats the cells and strains the electrodes, speeding up both kinds of ageing. Rapid chargers, the kind found at motorway services, push that power straight into the battery. In the Geotab data, charging power mattered more than climate or daily mileage (Geotab, January 2026). AC charging runs at 2,3 kW from a 3-pin socket and up to 7,4 kW from a home wallbox, since most UK homes have a single-phase supply; public posts go up to 22 kW. Every AC figure is capped by the car's onboard charger, and all of it is gentle for a battery built to take far more at a rapid charger.
On a road trip, rapid charging is the sensible choice. The effect builds up with frequency: a car rapid charged for most sessions ages faster than one that uses it a few times a month. Without a charger at home, plan AC charging where the car is parked anyway: at work, at the supermarket or overnight at a nearby post.
Fig. 2
Capacity lost after eight years, by charging habit
12%
mostly AC charging
18%
the average
24%
mostly rapid charging
One dot is 1% of capacity. Geotab, January 2026.
03 · Charge limits
Should you charge to 80% or 100%?
It depends on the chemistry: NMC and NCA batteries take the daily limit in your manual, often 80 to 90%, while LFP batteries go to 100% at least once a week.
Most long-range EVs use NMC or NCA cells, both nickel-based, which age faster when they sit full, especially in warm weather. A full charge just before a long trip does little harm; leaving the car full for days does more. Geotab found faster ageing mainly in cars that spent most of their time near full or near empty (Geotab, January 2026), so a charge limit set in the car deals with most of the risk.
LFP (lithium iron phosphate) batteries, fitted to many standard-range models such as BYD's cars, the MG4 with its standard battery and the Citroën ë-C3, tolerate a full charge well. Their voltage barely changes across most of the charge, so the car needs regular full charges to measure what is left: Tesla's Model 3 owner's manual recommends a 100% limit for LFP versions and a full charge at least weekly. The car's settings or specification sheet name the chemistry.
Fig. 3
Charge ranges by battery type
NMC or NCA, most long-range cars
LFP, many standard-range cars
0%
20%
50%
80%
100%
Day to day
Just before a long trip
Charge soon
Don't leave it parked here
Your owner's manual sets the exact limits.
Voldt® tip
Set the limit in the car or its app instead of unplugging early. Most cars let you raise it for one session before a trip and then return to the daily limit on their own.
04 · Heat, cold and parking
How do heat, cold and long parking affect the battery?
Heat adds about 0,4% a year of loss in hot climates, cold cuts range only while it lasts, and a car parked for weeks is best left at around 50%.
Calendar ageing runs faster in warm cells: Geotab measured about 0,4% a year of extra loss in hotter regions (Geotab, January 2026). Cold slows the chemistry, so the car limits charging current until the cells warm up, and range drops for the season. Preconditioning warms the battery before you drive or reach a rapid charger. Heat and cold affect the insulation of your cable as well, covered in how temperature affects your EV charging cable.
A parked car keeps ageing, most slowly at a middle charge and a cool temperature. Before a break of several weeks, set about 50% or the figure in your manual, and never let it run down towards empty: a deeply discharged battery ages fast, and the 12 V battery that wakes the car can go flat first.
Fig. 4
What the weather does to the battery
Frost
Range and charging speed drop for the season and come back as it warms up.
Cool and mild
The best conditions to leave a car parked for weeks, at around half charge.
Heat
Ageing runs faster, by about 0,4% a year in hot climates.
Geotab, January 2026.
Voldt® tip
In winter, leave the car plugged in overnight with a departure time set. It then warms the battery and cabin from the grid before you leave, so that energy comes from the socket instead of your range.
05 · Your cable
Does your charging cable affect battery health?
Not directly. The car sets the current the battery takes, whichever cable is plugged in; the cable decides whether you can charge on AC at all.
The car's onboard charger and battery management system set the current, watch the cell temperature and slow or stop the session whichever cable is plugged in. A cable rated below the onboard charger, such as a 16 A cable on a car that takes 22 kW, makes charging slower and leaves the battery unaffected.
A cable decides whether an AC routine works for you. A wallbox with a socket or a public post needs a certified Type 2 charging cable rated for your car's onboard charger: 16 A three-phase covers up to 11 kW, 32 A up to 22 kW. Without a wallbox, a portable EV charger lets you charge on AC from a sound 3-pin socket or a 32 A commando socket. A worn cable is a safety matter: loose contacts can overheat.
Fig. 5
Who has the final say over charging power
Battery management
has the final say
Onboard charger
takes, say, 11 kW
Cable
rated 11 or 22 kW
Charge point
offers, say, 22 kW
Each level can only lower the power set by the level below it.
Our verdict
An EV battery ages slowly, and three habits cover what you can control. A Type 2 cable lets you charge on AC at public posts and wallboxes with a socket, and a portable charger does the same from a 3-pin socket.
1
Charge on AC most of the time
2
Keep rapid charging for trips
3
Never park for weeks close to empty
Buy it if you charge at public AC posts, have a socketed wallbox or no wallbox at all
Skip it if your wallbox has a tethered cable and you never use public AC posts
Voldt® products for AC charging
Portable charger, 3-pin plug
8 to 13 A · up to 2,8 kW. For overnight charging from a sound 3-pin socket.
Portable charger, blue commando
Single-phase, 8 to 32 A · up to 7,4 kW. For a 32 A commando socket in a garage or on a driveway.
Safe use and warranty
- Plug a portable charger straight into a sound, earthed 3-pin socket, never an extension lead or adaptor.
- Stop using a cable with cracked insulation, bent pins or scorch marks.
- Where your owner's manual differs from this guide, follow the manual.
Voldt® cables and portable chargers are CE, UKCA and TÜV certified, with a 3-year warranty; terms and exclusions are on the warranty and complaints page.
CE · UKCA · TÜV · IP67 · 3-year warranty · 100-day returns
Frequently asked questions about EV battery degradation
Does rapid charging void the battery warranty?
Not usually, but check the conditions in your warranty booklet.
Is it bad to charge every night?
No. Plugging in daily to a set limit keeps the battery in its middle range.
Does hard acceleration wear the battery?
Less than you might think: in a Stanford study, stop-start discharge like real driving gave cells up to 38% longer life than steady lab cycling (Nature Energy, December 2024).
Can I leave my EV plugged in?
Yes. The car stops at its limit, and many use grid power to heat or cool the battery while connected.
How can I check my battery's state of health?
Many cars show it in the app or a service menu, and a dealer or independent battery test can measure it.
Is a used EV with 85% capacity a good buy?
It can be. At 2,3% a year, 85% fits a car of six or seven years; on a younger car, ask how it was charged, and check how much of the battery warranty remains.
Voldt® product team, product development and support
Develops Voldt® charging cables and portable chargers and answers the questions that reach Voldt® support.