Have had a search on the fora & not found anything useful on this topic, so thought I'd try asking direct - just in case my Google-fu is failing me
I've recently been doing occastional 2-gang replacements around the house to have USB ports available in various rooms; this is the one I've been using : 2-gang with USB I've finally got around to doing one of those in my study & thought I'd use it to power a Pi while I'm working on it (ie before I push it into service), but am a trifle puzzled with what I'm seeing ...
According to the 2-gang specs, this is supposed to have a 5v supply of shared 3.1A to the USB ports, but shared only if both sockets are used - ie only use a single device and you get 3.1A if the device wants to pull that much. To my recollection, (first question) this should be fine for a Pi3 B+, yes ? What I'm seeing, however, is the yellow spark symbol top-right of the Pi's display so it's not happy with what's being delivered.
My second question - can I (easily) find out from the Pi how much voltage / amperage it's actually pulling / getting ? The Pi works fine, of course, if I plug in a PSU or phone charger - but I'm trying to get awy from these in the various rooms.