Charging the MiFi

shahidhaque · EVDO Newbie Joined: 26 Nov 2009 Posts: 2

Well, I decided to give the Tekkeon cables with my battery. I've purchased them from the company website and will report my results with batteries that otherwise wouldn't charge the Mifi.

arizonauser · EVDO User Joined: 17 Nov 2006 Posts: 26

I have the Verizon MiFi. I am using the latest firmware update.

From here http://en.wikipedia.org/wiki/Enhanced_mini-USB
and else where, you can read:

...having colluded with Motorola to put an arbitrary 1.4 volts on pin X. This voltage violates the USB-IF standards, as pin X should either be tied to ground or not connected at all. Without this connection, the phone will refuse to charge, displaying "unauthorized charger" despite receiving the proper current. The phone will charge while connected to a personal computer only if the PC is running a special device driver...

This is the answer that all of you need to get past wondering why the MiFi sometimes charges and sometimes not. The MiFi must either have that Motorola circuit built into the end of the connector, OR, have the drivers installed on the laptop to charge. It is that simple. The stock MiFi charger includes this circuit in the connector.

This is so simple it is a joke. The "circuit" is just a 160K or sometimes a 200K resistor between pin X and pin Ground... A drawing is on http://pinouts.ru/Devices/mini-USB_pinout.shtml

Why does the Tekkeon MP1800 work?? Because the adapters that come with it have that circuit (resistor) built into the connector. (That is why the Tekkeon MP1800 can charge Motorola phones.)

Now go back and experiment some more and return here to post your results.

I have tested the MiFi and only know two things for certain: It draws more than 800mA when turned on plus charging... It charges just fine from 500mA supply if off (new firmware required for this option) and charging.

If you are wondering, I have tried removing all wires except pin 1 and pin Ground from the USB cables (which leaves only 5 volts and Ground) and the MiFi will not charge... but it will IF pin X has a resistor to Ground.

Pin X is the fourth pin on the connector, so some people call it pin 4, others refer to it as pin X.