Duracell Mobile Charger doesn't work with my USB devices

changcl

Newly Enlightened
Joined
Sep 25, 2008
Messages
16
I just got myself a Duracell Mobile Charger due to it's USB charging capability. However, I've tried my two main USB devices, a Motorola Raze from Verizon and a Ativa MP3 player.

The Raze would reject the charger as an "unauthorized" charger and the MP3 player simply didn't detect the charger at all.

I've checked the voltage from the USB port and it was putting out around 5V.

Any ideas? Do I have to modify the cable to make them to work with the charger? All reviews said good thing about this charger but I just couldn't make it to work for me.:mecry:

Thanks
 

VidPro

Flashlight Enthusiast
Joined
Apr 7, 2004
Messages
5,441
Location
Lost In Space
i have so MANY of these things now, i started turning them into Lights :)
here is what i have seen so far.

output to low for device to initiate charging
no visable resistance to initiate auto turn on
output to HIGH (on the one i bought because the other was to low) so the charge stops as "done" because of a voltage peaking.

then there is (aparentally) 2 ways to connect power to the USB small input pin, Me THINKS that depending on the PIN they connect some hot lead to, the devices can function differentally
AKA a wall power device might be seen different from a computer USB connected device, due to the computer is only supposed to have a .5A load max, and some wall chargers go over that.

round and round, this is some of what i found.

a too low power device can act different depending on the state of the battery
a device that uses AAs can require wery expencive Lithium AAs , because the alkaline drops in voltage from the load to much, even a ni-mhy can be to low of voltage for the boost curcuit to kick in.
(which would include a disclaimer that there probably is devices that would overheat with a lithium)

a too HIGH powered device was fixable (amasingly enough) by adding a usb extention of the cheap variety (rollup) it lowered the total output through wire resistance, and then it wasnt so hard on it.

so far i havent DESTROYED any of the multiple usb connecting devices with them , YET , thank goodness, but EVERY different one , and every different device has acted different.
Each of the charge items had different levels of output, and each of the electronic gadgets i connected had a different curcuit for doing the charging and charge stop and recognition, one combo would work with one device and not another, only ONE of the 5 will work properly with many different devices, without any special problems.

Variations included output voltage variations 5 no 5.5 ?
input voltage (battery) variations , determine if the boost curcuit functions and how. (voltage and current)
variations in total current output from 100ma to almost an amp

so i guess you just keep trying, and , taking them back, when they CLAIMED it would work with some specific device.

Someday Standard will have meaning.
 
Last edited:

shadowjk

Enlightened
Joined
Oct 21, 2007
Messages
451
Some devices that charge from USB these days will not take any power, or will not take more than 100mA, before it has negotiated with the computer at the other end that it is okay to increase consumption to 500mA. (there's a new spec that will let devices request more than this). Of course, those devices don't work very well if you just give them a USB cable with power and no computer to talk to on the other end :) Some devices do both the above, and also have a simpler method, where their supplied charger will have its datapins shorted with a resistor, so that the device will know it can pull full power from it even if nobody is responding on the other side. And of course, it isn't standardised at all, so it's difficult to make a generic charger that works with all the devices in the world :)
 

Marduke

Flashaholic
Joined
Jun 19, 2007
Messages
10,110
Location
Huntsville, AL
Motorola is picky about USB charge cables you are allowed to use. To use a generic USB charger, you have to get a special cable to enable charging the Razr phone.
 

tslrc

Newly Enlightened
Joined
Nov 6, 2004
Messages
193
Location
Ohio
Changcl - the thread here goes into a little more detail on the Duracell Mobile charger and cable I use for my Razor, starting around post 42 or so.
 
Top