answered
2014-02-01 21:30:26 +0200
According to the USB standard designated chargers (plugged to AC line) identify themselfes by the data lines (D+ D-) shortend together or connected with a resistor smaller than 200R (200 Ohm).
This behaviour protects the USB (2.0) ports in a PC that are limited to max 0.5A. The connected device will not draw more than 0.5A charging current.
Depending on the quality of the USB plug/cable and your personal "plugging skills" it could happen that the device will recognize connection to the powerlines first or only. The device then thinks it it connected to a USB port and will limit the charging current.
For an easy fix just plug the USB cable to the Jolla first, then plug the charger to AC line (just like martti has suggested, see above)
I checked with different chargers/cables and I got mixed results. Sometimes the Jolla asks for connection mode, sometimes it just starts charging so it correctly recognized the connection as connection to an AC charger.
I did same tests with my N9 and it always recognized the AC charger connection correctly.
I'm not sure about the following, but here are my two cents:
When you plug in the phone and it recognizes a current on the USB port a script is triggered. This script checks the connection of the USB datalines. Based on this the phone asks you to choose connection mode (happens when plugged to a PC) or directly starts charging.
So basically this way:
PLUG IN-->CONNECTION DETECTED-->TRIGGER SCRIPT-->CHOOSE CONNECTION.
But maybe it should look like this:
PLUG IN-->CONNECTION DETECTED-->TRIGGER SCRIPT-->TIME DELAY-->CHOOSE CONNECTION
Adding/increasing a time delay before triggered script checks dataline connection should always correctly identify the connection regardless of your plugging skills.
I'm not quite the hardware expert. I think this is, when the charger "identifies" as a PC or something, then the phone tries to request more power of it which the charger does not understand. Hopefully someone with more in-depth knowledge can explain better.
Venty ( 2014-01-03 15:22:32 +0200 )editYou need to insert the charger correctly. If you don't plug it in right (especially when really slow) it can sometimes cause some electrical gremlins which will cause it to be wrongly detected at first. It does start charging but it takes more time before it does in that case.
Philippe De Swert ( 2014-01-03 15:43:59 +0200 )editI've had this as well; my workaround is to just connect the micro USB to the phone before hooking it up to the AC mains.
martti ( 2014-01-05 00:02:25 +0200 )editI'm also familiar with this charging issue but the solution that @martti suggested has worked out quite nice though.
TimTTK ( 2014-02-02 14:59:54 +0200 )editThis happens to me quiet a lot with the original Jolla wallcharger/cable. Reconnecting solves this but anyway I've never experienced this with the N9 charger/cable.
Alex ( 2014-02-02 16:50:14 +0200 )edit