Asking for tips and ideas to check the car before buying

Hello and welcome to PriusChat!

Usually you would need a dealer to check out the battery health using diagnostic tools but there are a few things you could use as a proxy for a dying battery.

1. When the car is running, check to see that the battery maintains a charge. Toyota hybrids like to keep it around 60% for maximum longevity. On the battery meter in the car, that also roughly translate to 60% of the icon (note that a full charge in the battery display in the car is actually only 80% and an empty battery is actually only 20%. Again, this to maximise longevity). See if the battery meter stays steady as you test drive the car and it doesn't constantly drain to low charge and then back up again. The engine will also run more frequently than normal and won't shut down as often when stopped at a traffic light
2. Check the battery air filter. A well maintained car should have the filter cleaned or replaced. If it's dirty, then air hasn't been able to go into cool the battery and it could shorten the life

It depends on how the previous owner(s) treated the car but typically, under normal operations, Toyota hybrids should be able to run over 200,000km. My 2005 Prius lasted 245,000km before needing a new battery for example. Prius taxis run to 400,000-500,000km before needing a new battery but you can see, it depends on the operations.