After 4.5 years, I’ve just seen my highest estimated EV range: 65.5 kilometres (40.9 miles). While I do only have 25,000 kilometres on the odometer, I would have thought that age of the battery alone would have meant at least some range loss at this point. Thoughts?
Estimated range is a fictitious and overly generous and optimistic estimated value. In summer our range is estimated at 72km, in winter drops to 60-65km depending on the garage temperature. In reality I'm lucky to actually drive 7-8km for every 10km shown of estimated range in summer. Bottom line is don't trust the fuel economy computer for fuel economy or electric range. There is a reason why the trip meter graph only displays a range of 0-30 L/100km even when your car averages 4-5 L/100km - it makes the variability in the number less obvious for consumers to whine to their dealers about.
There is also the buffer in capacity to contend with. It's possible for the software to release some of that locked up capacity to compensate for loss in useable capacity.
You can expect some battery degradation over time but that rate is a function of charge/discharge cycles, age, and environment. Since you only have a 8kh/h battery you are not subjected to the additional fast-charge rate degradation that every is not worried about (yet...) 20-25 miles ain't nothing - and you have effectively unlimited ICE range. Best!
Without knowing the actual capacity when "fully charged" now versus when it was new, it's hard to go off the estimated range. I was getting similar numbers after 40,000km and 3 years back then before I traded it in. I was taking full advantage of the EV range so the engine really only ran on road trips. Toyota is also super conservative so there's a decent buffer on these batteries. I believe fully charged is only 81 or 82% true SOC.