Electric and plug-in hybrid vehicles rely on their battery more than any other component. At Complete Diagnostics, we now offer EV & PHEV Battery State of Health (SOH) testing, providing a fast, accurate assessment of battery condition, complete with an official battery health certificate. Whether you’re buying, selling, appraising, or simply owning an electric vehicle, our battery health test gives you confidence and clarity.
Our EV battery health test measures the current condition of your vehicle’s high-voltage battery and compares it to how it performed when new.
Using industry-leading testing technology, the assessment:
✔ Takes just 5–10 minutes
✔ Requires no battery removal
✔ Works on a wide range of EV and PHEV models
✔ Produces a clear, easy-to-understand certificate
This makes it ideal for used EV sales, trade valuations, fleet checks, and peace of mind for owners.
Each test produces a detailed certificate covering key indicators of battery condition and usage. These may include (subject to vehicle):
State of Health (SOH)
A higher percentage means the battery is closer to its original condition
A critical factor in vehicle value, range, and long-term reliability
Number of Slow Charges
Slow charging is much gentler on the battery
Helps preserve battery health over time
Number of Fast Charges
Frequent fast charging places greater stress on the battery
Can contribute to faster long-term degradation
Wh / Mile (Energy Usage)
A higher Wh/mile figure suggests more overall usage and increased stress on the battery.
Cell Imbalance
Healthy batteries have low imbalance
High imbalance (over 40 mV) can indicate battery degradation.
What this may mean:
Module Replacement
If certain columns consistently show higher values, it may indicate one or more battery modules were replaced. This causes some imbalance but is usually less severe.
Faulty Cells
If one or more columns are significantly lower than average, this often indicates faulty cells. These can negatively impact performance and reliability — vehicles with this issue are best avoided.
✔ Ideal for used EV & PHEV buyers
✔ Increases transparency in vehicle sales
✔ Supports accurate vehicle appraisals
✔ Perfect for fleet operators
✔ Peace of mind for EV owners
✔ Provides a realistic driving range mileage based on the battery’s current health
Battery condition can vary significantly between vehicles of the same age, this test removes the guesswork.
Our testing solution supports a wide and growing range of electric and plug-in hybrid vehicles.
View the latest supported vehicle list.
(Availability may vary by model and year, please contact us if you’re unsure.)
Get a professional battery health assessment in minutes, with a certificate you can trust.
Contact us today to find out more about an EV or PHEV battery test.
(Certificates provided on completion)
