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Hybrid Battery Test

Used electric and hybrid batteries

The part worth
most of the car

A used electric car is a battery with a car around it. Almost nothing written about that battery is sourced. Every figure on this site names where it came from and the day it was read.

Start with the numbers

A Toyota hybrid battery opened on the bench, every module numbered and its reading written on it in marker.
A hybrid pack Matthew Bolen opened and measured module by module. A Wrench Services job photo.
2.3%
average capacity lost per year across 22,700 vehicles
0.3%
of electric cars from 2022 onwards have needed a replacement pack
7
battery chemistries on the road, and only one changes how you charge
3
recall campaigns that superseded an earlier one, so a clean lookup can mislead

Three things almost every article gets wrong

There is no federal eight year mandate

Not for a used electric car. The statute says 80,000 miles and named three components, none of them the battery. The battery was added for model year 2027. The full story.

The degradation figure went up, not down

The widely quoted 1.8 percent a year came from a 5,000 vehicle study. The same researchers now report 2.3 percent across 22,700. Why.

A clean recall lookup is not proof

Three battery campaigns superseded an earlier one, so a car showing the old recall as completed can still need the new remedy. The three.

Who actually made the battery

Two companies make more than half the traction batteries on earth, and neither of them is American or European.

All 11 manufacturers Whose cells are in my car

Every chemistry on the road

And the one that is not here yet

What this site does not know

Published in full rather than hidden, because a reference that does not say where it stops is not a reference.

  • Tesla's owner manual pages refuse automated access, so every Tesla specific charging instruction here comes through Recurrent and the trade press rather than from Tesla.
  • The fifth generation Prius switching from nickel metal hydride to lithium ion is widely reported and was not confirmed at a Toyota source.
  • Battery warranty terms for Ford, Volkswagen, BMW, Audi, Polestar, Rivian and Toyota. Those seven refuse automated access or render only in a browser, so nothing is claimed for them.
  • Every recall and service campaign number, including the Chevrolet Bolt cell recall.
  • Whether the federal battery warranty and state of health provisions survived the February 2026 repeal of the vehicle greenhouse gas standards.
  • Any credible dataset on how often twelve volt batteries actually fail in electric cars.

Start here

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