[jwatte]

There are many lithium chemistries, and variations within chemistries.

My Nissan has over 30% loss after four and a half years. They clearly use lithium ion/polymer, the lightest but least durable chemistry.

Meanwhile, I have a lithium ferrous phosphate battery pack for a robot that has lost very little capacity over the same time.

It's pretty clear that different manufacturers use different design margins already.