You can get a small unit that plugs into the cars ODB diagnostics port and lets you see the cars health information on your smartphone.
We recommend doing this before buying so that you know the battery health.
Buying a Leaf is more about battery health than it is about mileage.
A 30,000km leaf with 100% battery is better than a 10,000 leaf with 80% battery.
Leaf Spy units come in WiFi or Bluetooth variants.
The WiFI units seems to be reliable.... WiFi Units on Trademe, They show up as a WiFi unit and you connect to them from your phones settings menu.
More info at the US EV Wiki
The app has built-in help text, which is also available as a PDF file. Separate help is available for iOS and Android. The latest version of the PDF manual is available by emailing the app's author. That email address and the required email subject line are given at the start of the in-app help text.
Cell Voltage Loss Inspection
In certain circumstances, Leaf Spy will perform a Cell Voltage Loss Inspection test for you. The test is based on a 2011 publication by Nissan, and evaluates whether the battery has any officially weak cell pairs. When it's performed, you can see the result in screen 1, which is the main famous Leaf Spy screen with the histogram of 96 cell pair voltages. The result message is either "All Cells OK" in green, or "Weak cells:" followed by a list in red. This replaces the line of battery temperature readings near the bottom of the screen.
The test is done when:
- the car is On, not just in Accessories mode, and
- the state of charge is down below the low battery warning level, and
- there is a spread of at least 200mV between the cell pair voltages.