--- a/pirelli/battery	Sun Mar 15 09:00:05 2020 +0000
+++ b/pirelli/battery	Wed Oct 21 22:40:28 2020 +0000
@@ -25,3 +25,16 @@
 3663	10
 3539	5
 3370	0
+
+Apparent voltage thresholds for UI battery icon change, determined by powering
+a decased phone from a bench power supply, turning the voltage knob, rebooting
+the phone each time and observing the battery icon:
+
+from 3 to 4 bars:      between 3.88 and 3.89 V
+from 2 to 3 bars:      between 3.77 and 3.78 V
+from 1 to 2 bars:      between 3.72 and 3.73 V
+from 0 to 1 bar:       between 3.52 and 3.53 V
+"Battery Low" on boot: between 3.51 and 3.52 V
+
+Below 3.37 V Pirelli's fw refuses to boot: starts, but then immediately powers
+off.