[kevamiga]

Have noticed, that both my 6220 classic and 5800XM have the same problems on USB Charge.

Using a CA-100 USB > Nokia power convertor.

1. It never charges fully...

2. If the charge in the phone is low, it wont start charging, but gives the Charging > Not Charging problem.

Im guessing USB @ 500MA isnt enough power to get the ball rolling, perhaps the nokia has some sort of "charge me as fast as you can" mode when the power is low on the phone.... grim.

Oh well... works well as a "Saver" rather than a "Charger"...

So to add... is the Charging / Not Charging error caused by the phone not detecting enough juice from the charger... hmmm 

[grschinon]

Some USB ports are able to give off more juice than others - it's pretty random in fact. If your phone refuses to charge using a USB-to-2mm adapter such as the CA-100 it's because the rating of the USB port you're using is just a little low. It's not "wrong", just at the lower end of the tolerance.

Phones that are designed to be charged off USB ports from the outset (N85, N97, 8800a/sa/ca etc.) are more aware of the tolerances involved and account for them in the electronics.

[kevamiga]

Tried loads of different PC's... its always the same. Got 2 CA-100's here too.

Odd how it works fine if i start the charge when the phone has over say 40% left in it though? 

[el_loco]

This is in a way "normal"

The max. current that a USB 2.0 can provide are 500 mA, the typical normal current is 150 mA.

A normal wall charger provides about 800 mA.

So the USB charging option at best is what used to be called a trickle charge or slow charger. When the phone is doing almost anything like turning up the screen it consumes more than 150 mA, so the USB charge can't keep up.

If the battery is flat you should USB charge with the phone OFF or in idle not running anything else. Even USB mass storage will drain the battery.

Also the time it takes to reach full charge is much longer than with a wall charger. 

The BATTERY FULL message appears at about 85-90% of the battery capacity, I don't know why this is the reason but I think if you leave it after it gave the message it will reach full charge.