Capacity is measured a number of different ways.
CCA are completely irrelevant in our EVs. Crank starting a conventional car requires very large current flow (many hundreds on a cold day) for brief time periods, just a few seconds typically. That is a very different requirement from what our cars need. CCA is defined as the number of amps a battery can supply, in theory, at 0 degrees F for 30 seconds without dropping below a set voltage. I mention it here for newbies who are dealing with EVs for the first time. Clearly not relevant to our needs.
Batteries built to supply large CCA values are physically different from batteries optimized for sustaining output under lower loads for longer time periods. The latter batteries are a better fit for our cars.
Look instead for "reserve time", usually quoted in minutes, or amp hours (Ah). Reserve time is defined as the number of minutes the battery can supply 25 amps before dropping below a set voltage at 80 degrees F. Amp hours are usually quoted at the "C20" rate, meaning the number of amps the battery can supply for 20 hours before dropping below a set voltage at 80 degrees F. Lower CCA, however, is not a bad thing.
Capacity is not a fixed, linear thing - higher loads draw down a battery disproportionately faster than small loads do - it's not linear. Furthermore, the same battery tested under lab conditions will perform differently from charge to charge. So it pays to understand what standard capacity is being rated for when considering different batteries, and also to recognize that batteries are not so deterministic as one might expect.
Empty-nesters - NW Denver-Boulder Area
2019 Leaf SL Plus
2015 Audi Q5 TDI
2007 BMW Z4 3.0Si
2012 VW GTI