Batteries have different capacities at different C rate discharge. 1C is the amperage listed as the battery amp hours, but at higher discharge, batteries have a lower capacity. Some batteries handle higher discharge better than others (closer to the rated capacity). You can of course estimate the battery capacity in watt hours, but it’s not how the battery is classified (eg in a data sheet)
Sort of. C rate discharge is just another (confusing) way of state CDR. You might as well just say the CDR in amps. C rate is really just to give a comparison on battery chemistries to illustrate how performant different chemistries can deliver power at a normalized value (to illustrate how the battery chemistry could in theory scale up)
For example, 1C is rated continuous discharge amps, which means a 1C rated battery will provide 1 * Ah. So if a 20,000 mAh battery is rated for 20,000 mAh @ 1C, it will (in theory) discharge 20,000 mAh at 20A in one hour.
> You can of course estimate the battery capacity in watt hours, but it’s not how the battery is classified (eg in a data sheet)
You're right but this is irrelevant because real life usage highly varies. Data sheets are just guides.