This battery lasts the life of the router under the operating environmental conditions specified for the router, and is not field-replaceable.
But who determines its lifespan?
Knowing there is a battery set to fail and I can’t simply replace it makes me physically uncomfortable. Enough so that I’d rather it not have RTC.
Thanks Cisco.
Generally the chemistry and any features of the battery.
https://wikipedia.org/wiki/Button_cell#Type_designation
C means Lithium. The R means Round.
The IS IEC spec that defines the coding is 60086-3