Battery level

[sm-Fifteen]

So I noticed my batteries were about to die when rumble started to make my controller disconnect. I started monitoring the battery level to see what would happen and here are the results.

• Byte 10 of the energy update is indeed estimated battery level. It changes in increments of 4. I'm not entirely sure how it's calculated, see graph.
  • Note that I slotted the batteries right before I started the recording, so if the Steam controller relies on battery history to determine the remaining percentage, that metric would be made unreliable.
• The Steam Button started blinking when the reported battery level reached 0%. It looked no different than the one it normally does when it's seeking for the receiver, despite still being connected.
• The controller worked fine up until the point where it died for the last time, at a reported 1.617V. Getting it to power on got really tricky past 2.2V, however, and anytime I tried to get the rumble emulation to work during the whole experiment (even at 2.5V at the beginning), the controller would shutdown.
  • While attempting to power on, the controller would sometime brown out midway though the power-on chirp and stay "on" (power led at full brightness, but still not connected, holding the Steam button does not turn it off)
• Note that all those measurements are in volts while what matters here is how much power (watts) the SC is able to gett from the bateries, so we're still missing half of the equation.

sc-dead-batteries.pcapng.zip