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How Ever Estimates EV Battery Health?

Updated: Aug 2023

Battery health estimation is one of the most critical aspects of choosing the right pre-owned electric car. Luckily, there are a number of different but useful approaches to estimating battery health - with each approach bringing its own set of strenghts and weaknesses. Below, we explain how Ever ensures sufficient battery health for all electric cars that we buy and sell.

How Ever Estimates EV Battery Health?

To make electric car buying and selling as easy and trustworthy as possible, Ever ensures sufficient battery health following a four-step process.

1. We start by sourcing EVs with reliable batteries and warranties

Ever's sourcing is focused on younger, more reliable EV makes and models. This means focusing on battle-tested models, such as Tesla Model 3 and Model Y, Ford Mustang Mach-E, Nissan LEAF, Chevrolet Bolt EV and Bolt EUV, Kia EV6, Hyundai IONIQ 5, Audi e-tron, Rivian R1T and R1S, Volkswagen ID.4, BMW i4, and Ford F-150 Lightning.

Each of these EV models comes with at least 8 years and 100,000 miles in battery warranty, as provided by their manufacturers. These battery warranties provide additional assurances and peace of mind for EV buyers. For more on EV warranties, see our EV Warranty Guide.

2. We then run statistical battery health estimation on each EV

Even before sourcing an electric car, Ever runs a remote, statistical battery health estimation. This is done using market-leading battery diagnostics tools, and it gives Ever a statistically accurate estimate of the electric car's expected battery health.

These estimates are based on a large set of data on similar electric cars' remaining battery health and range – with similar electric cars defined based on vehicle make, model, year, trim, odometer mileage, age, and location.

3. We also look at the EV's own battery diagnostics

Ever also takes a look at the electric car's own battery diagnostics, as made available by the vehicle's manufacturer. Different makes and models have varying degrees of OEM battery diagnostics available.

For many electric cars, such as the latest Tesla models, the OEM battery diagnostics are relatively accurate and trustworthy. That being said, a manufacturer's diagnostic is always somewhat biased, and it's good to complete high-accuracy third-party diagnostics to complement this.

4. Finally, we run a physical battery diagnostic

This is perhaps the most important part of our battery health estimation, as its allows us to focus on the unique characteristics of a particular electric car and its battery. In the physical battery diagnostic, we connect to the car, reading and testing for several parameters, including the car's battery history, battery controller performance, high-voltage battery state, low-voltage battery state, and relevant communication & signal systems.

Data on battery history covers the car's charging cycles, state-of-charge and depth-of-discharge histograms, equalization times, average energy consumption, estimated battery management system health, and more.

Testing for battery controller performance refers to ensuring the car's temperature and cell voltage sensors are functional and the estimated state-of-charge and state-of-health are plausible.

Diagnosing high-voltage and low-voltage battery systems refers to testing for battery current, voltage, cell voltage deviations, and cell temperature deviations.

Diagnosing vehicle communications & signal systems refers to confirming that all relevant signals are available, plausible, sampled at the right rate, and of sufficient qualilty.

Note: In some instances, the make, model or trim -specific realities may not allow for a statistical (step 2) or physical battery (step 4) diagnostics described above. Even in these instances, we run the diagnostics we can and provide the related information to EV buyers.


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