TI has a FAQ on their site:
How long does the charge last on the TI Rechargeable Battery?
For student use, the TI Rechargeable Battery is expected to last up to two weeks of normal use on a single charge. For classroom use,
the TI Rechargeable Battery is expected to last up to five days of normal use on a single charge.
All I want is realtime alarms sent when a log entry matches a pattern.
SEC simple event correlator might be what you're looking for.
It is masked but always present. I don't know who built to it. It came before the first kernel.