I have one of those in-line USB meters on one of the ports of my 6-port USB chargers. The charger is one of the Blitzwolf ones that sits flat and has flip-up covers over the USB ports.
I have one phone (actually I haven’t tried others), an Elephone P3000S, that, when I charge it on the USB port that has the in-line meter, if I go back and check, the phone is down to 0. If I put the phone on one of other ports on the same USB charger, it charges to 100.
I think this same thing happened when I had that USB meter on another USB charger I have.
Anyone seen anything like that? Is it possible that the USB charger would cause the phone to drain like that?
I think that you’re saying that the battery itself has a protection circuit, like we have in the batteries we use for our lights, and that the meter is somehow causing the batteries protection circuit to trip?
I think that when this happened, the phone wouldn’t even turn on (i.e., it actually thought that there was not enough power). Then, when I moved the phone (and the battery) to a different micro-usb cable (that had no meter on it), it would start charging at low % and increase from there. If it was the protection circuit tripping, and I plugged into another non-metered port, wouldn’t the starting voltage in the battery have been, for example, maybe like 50% or something?
I guess the bottom line is I can’t charge the phone with that particular meter on the charge port?
Actually, I was thinking that the meter measures both voltage and current (voltage and amps), so maybe it was sucking the power out of the battery?