“Never charge past 80 per cent” is the most repeated piece of electric-car advice and it is wrong for a large and growing share of cars on sale. Whether you should charge to 100 per cent depends entirely on your cell chemistry — and for LFP cars the manufacturers actively tell you to do it.
The short answer, by chemistry
| Chemistry | Daily charge target | Why |
|---|---|---|
| LFP (lithium iron phosphate) | 100%, and at least weekly | Tolerates a full charge, and needs one to keep its state-of-charge estimate accurate |
| NMC / NCA (nickel-based) | 80%, with 100% before a long trip | Time spent at high state of charge accelerates calendar ageing |
If you take nothing else from this article: check what is in your car before following advice written for someone else’s.
Why nickel cells prefer 80 per cent
A lithium-ion cell ages two ways. Cycle ageing comes from charging and discharging. Calendar ageing happens while the car sits there doing nothing, and it is faster at high state of charge and at high temperature.
A nickel-based cell held at 100 per cent keeps its cathode at maximum voltage, which drives slow side reactions at the electrode surfaces. Sitting at 100 per cent in a hot car park is roughly the worst thing you can do to an NMC pack — and it is also completely avoidable.
Hence the 80 per cent advice: it is not about the act of charging, it is about the hours afterwards. Charging to 100 and leaving immediately on a long drive is fine. Charging to 100 every night and leaving the car on the drive is what the advice is trying to prevent.
Why LFP is the opposite
LFP is more tolerant of a full charge chemically, and it has a specific reason to want one: its voltage curve is remarkably flat. Across most of the usable range the cell voltage barely changes, which is excellent for delivering consistent power and terrible for working out how full the pack is — voltage is the main signal a battery management system has.
So the estimate drifts. A full charge gives the system a known reference point to recalibrate against. Owners who keep an LFP car between 30 and 70 per cent for months often report the range readout becoming unreliable, then correcting itself after one full charge — that is the calibration, not the battery.
The trade LFP asks for elsewhere is real: lower energy density, so a heavier pack for the same range, and a bigger cold-weather penalty. We cover that in do EVs lose range in cold weather and in full on the LFP reference page.
How much does any of this actually cost you?
Less than the intensity of the online debate suggests. Published fleet data puts typical capacity loss at roughly 2 to 2.7 per cent a year depending on vehicle class, and the same dataset finds charging behaviour matters more than charge limits: vehicles doing more than about an eighth of their sessions on DC above 100 kW degraded at up to 3 per cent a year, against roughly 1.5 per cent for cars charged mainly on AC.
In other words, where you charge appears to matter more than how full you fill it. If you want one habit to protect the pack, charge on AC at home most of the time and save rapid charging for journeys.
And put the numbers in perspective: at 2.7 per cent a year, a pack is still near 80 per cent after eight years — comfortably above the 70 per cent floor at which the warranty would replace it. See best EV battery warranties for what that floor actually means.
What we cannot tell you
How fast your particular model degrades. Nobody publishes per-model degradation data: the one fleet dataset large enough to matter anonymises the models, no manufacturer releases its own, and no independent body measures at that scale. Any site showing you a model-by-model degradation table is estimating.
Our own eight-year projections use the published class rate, are labelled as estimates everywhere they appear, and the method is on the methodology page. Two SUVs on this site show the same figure because we genuinely do not know which of them ages better.
Frequently asked questions
Can I charge my LFP car to 100% every day?
Yes, and manufacturers of LFP cars generally instruct you to reach 100 per cent at least weekly. The chemistry tolerates it and the state-of-charge estimate needs it.
Is it bad to charge my NMC car to 100% occasionally?
No. Charge to 100 before a long trip and set off. What accelerates ageing is sitting at 100 per cent for long periods, especially somewhere hot — not the charge itself.
What about the bottom of the range — should I avoid 0%?
Yes, more so than the top. Leaving any lithium chemistry at a very low state of charge for weeks risks deep discharge, which is genuinely damaging. If you are storing a car, leave it around half full.
How do I find out which chemistry my car uses?
It is on every vehicle page on this site with its source. One warning: the same model name can carry different cells depending on the plant that built it, and manufacturers rarely announce the change — so check your own car’s build rather than assuming the specification applies universally.
Sources
- Geotab — EV battery degradation study: class-average annual loss and the effect of DC fast-charging share
- Chemistry behaviour, energy density and cold-weather figures with their individual sources: our LFP and NMC reference pages.
- Per-car chemistry and warranty terms: the vehicle pages on this site, each credited with the source and the date read.