BEVDiag: EV Battery Health

Check the state of health (SOH), capacity and degradation of your electric car's traction battery with an OBD2 ELM327 or STN adapter. BEV Diag shows what the battery management system reports: state of charge, health, capacity in Ah, temperatures and the voltage of every cell, so you can spot a weak cell before it costs you range.

WHAT IT IS FOR
• Before buying a used EV: check the battery before you pay.
• When range drops: see whether it is the whole pack or a single cell.
• When selling your car: the battery card is a clear proof of its condition for the buyer.
• Every day: track battery degradation over time and record your drives.

FREE
• Connect your adapter and check that it talks to your car.
• Live: state of charge (SOC), state of health (SOH), pack voltage and current, and odometer.

FULL VERSION (one-time purchase, no subscription)
• BEVCloud - detailed AI report about battery condition in PDF.
• Cell voltages: every cell on a chart, with the lowest, highest and the spread.
• Capacity (Ah), module temperatures and counters from the battery controller (Hx on the Nissan Leaf too).
• A dashboard laid out separately for each car, with gauges and charts.
• Road test: a guided 20 to 80 km/h acceleration test with charts of power and voltage sag under load.
• Session recording: drives logged with GPS, the route on a map, export to CSV or JSON.
• Battery card: a shareable summary of the battery's condition, handy when buying or selling a used car.
The purchase comes back by itself after a reinstall or on a new phone with the same Google account.

SUPPORTED CARS
• Nissan Leaf AZE0 (2013–2017), 24 kWh
• Nissan Leaf ZE1 (2018+), 40 kWh and Leaf e+ 62 kWh
• Nissan Leaf AZE0 (2013–2017), 30 kWh
• Nissan Leaf ZE0 (2011–2013), 24 kWh
• Renault ZOE ZE20 & ZE40

EXPERIMENTAL SUPPORT:
• Kia e-Soul (2019+),
• Kia e-Niro,
• Hyundai Kona Electric, 39 and 64 kWh

TESTED ADAPTERS
• Konnwei KW905 (Bluetooth LE and Classic)
• Vgate iCar Pro (Bluetooth 4.0, Bluetooth 3.0, WiFi)
• ELM327 v1.5 adapters ("BT mini", "OBDII")
• Other ELM327 and STN adapters, such as OBDLink, should work.
Connects over Bluetooth LE, Bluetooth Classic or WiFi. Not every adapter works with every car, so check yours in the free version before you buy.

PRIVACY AND SAFETY
• The app only reads data from the car. It changes nothing in it.
• No account, no ads, no tracking. Recordings stay on your phone until you share them.
• Do not use your phone while driving.

BEV Diag is not affiliated with Nissan, Kia or Hyundai. Nissan, LEAF, Kia and Hyundai are trademarks of their respective owners.

Recent changes:
- Nissan Leaf: corrected battery history; history and identity listed on the Data tab.
- Renault ZOE: profile corrected using data from the first real cars.
- Battery card headline now fits each car.