EV Battery Health: What Actually Degrades, and What It Means for Buyers
Every lithium ion battery loses capacity over time. The question that matters is not whether it happens but how fast, and on that the real world data has been considerably more reassuring than early predictions.
Here is what actually causes degradation, what the warranties cover, how to read a used electric vehicle’s battery, and what changes when one is shipped.
What Degradation Actually Is
Two separate things get confused.
Capacity loss means the pack holds less energy than when new, so range falls. This is the one people mean, and it is gradual and largely permanent.
Power loss means the pack cannot deliver or accept energy as quickly, which shows up as reduced acceleration or slower charging rather than reduced range. It is often temperature related and partly recoverable.
The pattern in practice is a relatively quick initial drop in the first year or two, then a long slow decline. That shape surprises owners who watch the first year and extrapolate a straight line, which would be far too pessimistic.
What Causes It
Four factors, in rough order of impact.
Heat. The largest one. Sustained high battery temperature accelerates chemical aging, which is why thermal management matters enormously and why vehicles with liquid cooled packs generally age better than those with passive cooling. Hot climates are harder on packs than cold ones.
Time. Calendar aging happens regardless of use. A pack degrades sitting in a garage, just more slowly than one being cycled hard.
Fast charging. Regular use of high power DC charging generates heat and stresses the cells more than slower charging. Occasional fast charging is what the system is designed for; exclusive reliance on it is harder on the pack.
State of charge habits. Sitting at very high or very low charge is harder on a pack than sitting in the middle. This is why manufacturers commonly recommend a daily charge limit below full and a full charge only before a long trip.
What the Warranty Actually Covers
This is the part worth reading before buying, new or used.
Federal requirements set a minimum warranty period for electric vehicle batteries, and manufacturers commonly exceed it. Critically, most battery warranties cover capacity retention below a stated threshold, frequently around seventy percent, rather than any loss at all.
So a pack that has lost fifteen percent of its capacity is degrading normally and is not a warranty claim. That is not a loophole, it is the design intent, and it is the number to have in mind rather than an expectation of no loss.
Two other things to check. Whether the warranty transfers to a subsequent owner, since that materially affects a used vehicle’s value. And what remedy is specified: repair of individual modules, or replacement of the pack.
Buying a Used Electric Vehicle
The battery is the single most valuable component, so its condition is most of the purchase decision.
Ask for a battery health report. Most manufacturers can produce one through a dealer, and some vehicles display an estimate in the settings. An independent assessment is also possible, and on an expensive vehicle it is worth paying for.
Ask about charging history. A vehicle that lived on DC fast charging in a hot climate has had a harder life than one charged slowly at home in a mild one, even at identical mileage. Mileage alone is a weaker predictor for an electric vehicle than for a combustion one.
And check remaining warranty coverage and whether it transfers. A used electric vehicle with several years of battery warranty left is a different proposition from one just outside it.
How Owners Can Slow It Down
Four habits, all easy.
Charge to a daily limit below full, commonly eighty or ninety percent, and save the full charge for trips. Avoid leaving the vehicle at very low charge for long periods. Use slower charging for routine top ups and fast charging when you actually need it. And park in shade or a garage in hot weather, since ambient temperature affects pack temperature even when parked.
If a vehicle is going to sit for months, most manufacturers recommend leaving it at a middle state of charge rather than full or empty, and plugged in where the vehicle manages this itself.
What Changes When You Ship One
Electric vehicles ship routinely, and three things are worth saying at booking.
Weight. An electric vehicle is typically several hundred pounds heavier than its combustion equivalent because of the pack. Trailers have legal weight limits, so declaring it electric lets the carrier plan the deck properly.
Charge level. Carriers generally prefer a charge somewhere in the middle rather than full or empty. Enough to load, move and unload, without sitting at a high state of charge for a week.
How it moves. Some electric vehicles cannot be put in neutral and rolled the way a combustion car can, and some have specific transport modes. If yours has a procedure, write it down and hand it over with the key rather than assuming the driver knows that model.
Beyond that it is an ordinary move. What drives the price is set out in our page on what determines the cost of shipping a car.
Common Questions
How fast do EV batteries degrade? A relatively quick initial drop, then a long slow decline. Real world data has been better than early predictions.
What causes the most damage? Heat, followed by calendar aging, heavy reliance on DC fast charging, and sitting at very high or very low charge.
Does the warranty cover any capacity loss? No. Most cover retention below a stated threshold, often around seventy percent, rather than gradual normal loss.
What should I check on a used EV? A battery health report, charging history, climate it lived in, and whether the battery warranty transfers.
What charge should it have for shipping? Somewhere in the middle. Say the vehicle is electric when booking, since weight affects the load plan.
Get a Quote
Call Ship A Car, Inc. at (866) 821-4555 with both zip codes, your date range and confirmation that the vehicle is electric, or price the move with the instant calculator.
