On Wednesday, October 07, 2026, at 5:20 PM, Dan Cross wrote: > I'm mystified about where you came up with the 1.5A number you mentioned earlier. It's the amperage provided by the powered port of my T420. At least, I read that somewhere, might have that wrong.
On Wednesday, October 07, 2026, at 5:20 PM, Dan Cross wrote: > Does the laptop tell you how much current the port is drawing when these things are plugged in? >From here: https://forums.linuxmint.com/viewtopic.php?t=366919 "As far as I'm aware not any system's USB-implementation has hardware to measure *actual*, live draw; this would be information unavailable to any software, be it Windows, Linux or BIOS/UEFI-based." and: "When you type usb-devices | less into a terminal you're presented with your devices' advertised *maximum* draw in the MxPwr fields." I get MxPwr=98mA, which is tiny. At least, that is the only output that is for a usb device, so.. so so much for the 1.5 number I quoted above. -_- On Wednesday, October 07, 2026, at 5:20 PM, Dan Cross wrote: > how would you know whether it was the mouse, or the adapter? This goes to show how little I thought about the problem. Reflecting on it now, I thought of the adapter as being just a bunch of wires, not an active electronic device that would actually draw power. Without the mouse attached, I assumed it would just act as an extension of the pi, with no current flowing. With no current flowing.. no power consumed. So the fact that it reacted at all with just the adapter attached was an eye-opener. ------------------------------------------ 9fans: 9fans Permalink: https://9fans.topicbox.com/groups/9fans/Td94105a3d5018162-M5c834a8ad865bcf0150d5aad Delivery options: https://9fans.topicbox.com/groups/9fans/subscription
