Re: MiFi and Charging
mikebob
Newbie

I finally managed to figure out the proper cabling to get the Verizon Mifi 2200 to charge using a generic USB charger. To recap the problem... The mifi device will only charge when using the supplied micro usb charger, or when connected to a computer USB port using the supplied micro USB cable. When connected to a computer, the device reverts to it's connected data mode, which turns off the wifi ssid broadcast and requires the Verizon access manager application to be launched. Most third party chargers will not work... including most 12V lighter to USB adapters, and most backup battery solutions.

 

Here is what is going on... Per the USB specification, Pins 1 and 4 are 5V power and ground respectively. Pins 2 and 3 are data+ and data-. In most chargers, pins two and three are tied via a pullup resistor to the 5V line. If you measure the voltage on 2 and 3 you will see around 3V, equivalent to a logic high state. This has something to do with allowing the device being charged to identify whether it should be in a fast or slow charging mode. More importantly, it is what the Apple iPod expects to see . So, anyone wanting to build generic USB chargers will probably implement this way in order to tap into the single largest device market around. Unfortunately, the mifi does not like the logic high on pins 2 and 3. I haven't yet sorted out why, but when it sees logic high on pins two and three, it refuses to go into charging mode.

 

The solution is to use a cable where pins 1 and 4 (5V and GND) are carried straight through. Pins 2 and 3 need to be disconnected from the charging source and shorted together at the Mifi end. If this was a miniUSB instead of a microUSB, it would be what is called a "charge only" cable. I have not found any vendors yet for a charge only microUSB cable so I went ahead and performed surgery on a standard microUSB cable. I took a standard USB cable, cut it and then connected it to a microUSB connector from an old Motorola bluetooth headset charger.   Interestingly, the microUSB connector from the Moto charger  already has pins 2 and 3 shorted together internally so all I had to do was connect 5V and ground and heat shrink tube the whole thing. With this cable I can charge the mifi from any generic USB port, including those on 12V lighter adapters, and rechargeable backup batteries. In addition, I can also connect the Mifi to my laptop to charge while continuing to access the Mifi via wifi. 

 

Only word of caution...  You really need to connect the Mifi to your computer using the standard data cable on occasion, say once per month.  The reason is that it is only in this mode that you will receive notifications of S/W updates and/or the need to update your PRL. (preferred roaming list).

 

 

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Re: MiFi and Charging
rachelami
Newbie

Thanks so much for sharing this. The USB charging issue has been driving me nuts ever since I bought this thing. Sadly, I had already spent close to $50 (excluding a second MiFi battery) on micro USB cables and USB car chargers for this thing before I came across your post. So far, the only non-OEM device I had found that charges the MiFi is a $30 Verizon-branded car charger with a retractable micro USB connector.

 

Does charging via computer take substantially longer than using the supplied AC adapter? I left the MiFi connected to the PC via the supplied cable and after a few hours it showed no indication that it had charged at all. For the record, the charge indicator on the power button seems very unreliable, but thankfully, someone had the foresight to include the battery level indicator on the MiFi's admin page (192.168.1.1).

 

Today it finally dawned on me to try connecting the MiFi (and power source) to this little electricity usage monitor I have (called the Kill-a-Watt). With a low battery, I connected the MiFi to the supplied AC charger and connected that to the Kill-a-Watt. It showed that the charger was drawing 0.11 amps. Next I tried charging with a standard micro USB cable connected to an iPhone charger. This time the Kill-a-Watt showed Zero amps, but would jump to 0.05 amps whenever data was being sent/received.

 

It's interesting that your Motorola cable already had pins 2 and 3 shorted. I once tried charging my wife's Motorola phone using a USB mini cable connected to the PC and it did absolutely nothing.

 

Thanks again!

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Re: MiFi and Charging
rulerofthemoon

I've had excellent results using an iGo charger with the microUSB tip.  It charges perfect every time AND it allows rebroadcast (wifi) while it is charging.  I've only used the car charger but am considering getting the wall charger since the included wall charger is not reliable.

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Re: MiFi and Charging
rachelami
Newbie

I should have known the iGo tip would work. I almost bought one to try but decided instead to play it safe and order another battery. :smileymad:

 

It really is a shame that such a great little device is plagued by issues like these.

You can't shut it off while it's being charged.

You have to drill down into the configuration settings via WiFi from a browser just to change the standby settings.

The charge indicator on the power button is dang near useless. It would be like replacing the fuel gauge in your car with two idiot lamps that alternate between 'empty' and 'not empty'.

Charging options are hit and miss. It's like what happened when Apple first dropped support for 12 volt chargers - you didn't know what would work until after you bought the charger and tried it out.

 

The one thing that's still unclear at this point is whether the MiFi charges in tethering mode. The Access Manager software displays a battery icon but doesn't seem to indicate whether it's charging or not. Oh well, it doesn't matter much now that I've followed MikeBob's cable modding tip. Any ideas for a standalone charger for a spare battery?

 

It would be nice if someone could develop an app for the iPod Touch that would make the configuration page more accessible from a small screen device.

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Re: MiFi and Charging
bmclaurin
Newbie

*** Make Your Own Custom Mifi 2200 Charging Cable ***

 

Just wanted to pass along that mikebob's solution worked for me as well. It really is *very* easy to make your own micro USB charge-only cable that will work with your Mifi 2200. I used a spare Blackberry micro USB data cable. There are at least two approaches you can take to accomplish this.

 

1. The Quick and Dirty Way - Find a spare micro USB cable lying somewhere around your house, apartment, office, etc. Use a utility knife to carefully cut a ~1" slit running lengthwise through one side of the insulation. Cut just deep enough to expose the 4 colored wires inside. Your cable might also have an inner shielding material (usually a wire mesh type material), and you'll need to cut through this layer to expose the 4 colored wires. Find the white and green wires, and cut both of them completely through. Leave the red and black wires uncut. Then strip away a small amount of the insulation from the white and green wires *on the micro USB connector side of the cable* and connect those two wires together, thus basically shorting them together. The shortcut way is to just twist them together and maybe wrap a tiny piece of electrical tape around the newly created junction. Better still would be to solder the wires together. Leave the white and green wires on the standard connector side of the cable cut completely through (i.e., do not connect them). Now firmly wrap some electrical tape around the outer insulation of the sliced section of the cable. That's it, you're done.

 

2. The Slightly Better Way - My original Blackberry data cable was about 3-4 feet long, and I wanted to shorten it to ~18", so this was a great solution for me. For this method, I recommend soldering the new connections together for better conductivity and durability. But don't be scared away by the soldering--no expertise is necessary for this procedure. I'm just a hack when it comes to soldering, and my "skills" were more than adequate for this job (and so are yours). Here are the steps:

 

a. Cut the original cable completely through in two places (I cut ~9" from each end, but choose your own preferred length). Toss the middle section aside, as you won't be needing it anymore. You'll be using the two end pieces to construct your custom cable--one of these ends has a standard Type A connector, and the other end obviously has the micro USB connector.

 

b. Strip away ~1" of the outer insulation, as well as the inner shielding material, from where you just cut on both pieces of cable, to expose the 4 colored wires (red, black, green, and white) on each section of cable.

 

c. On the micro USB connector side of the cable, strip away a small amount of insulation from all 4 wires. Solder the white and green wires together, thus shorting them together. Put a tiny piece of electrical tape around the new junction to insulate it.

 

d. On the standard Type A connector side, snip the exposed portion of the white and green wires completely through, as you won't be using the white and green wires on the standard Type A connector side of the cable. So just leave the white and green wires disconnected on this side of the cable. That should leave you with just the red and black wires, from which you should then strip a small amount of insultation.

 

e. (Optional) Slide a ~2" piece of heat shrink tubing over one of the two sections of the cable (doesn't matter which section). This will be used to cover the "surgical scars" once you are done, as well as to provide some strength and durability to the finished cable.

 

f. Join the two ends of the cable together by soldering red-to-red and black-to-black. Put a tiny piece of electrical tape around each of the new junctions (separately) to insulate them from each other.

 

g. Firmly wrap some electrical tape around the entire "surgical area" of the cable to hold it all together.

 

h. (Assuming you followed optional step e) Slide the heat shrink tubing over the electrical tape and apply heat to shrink it to the form of the cable.

 

i. Congratulations...you're done with your custom charging cable.

 

I am now able to use this cable to charge the Mifi 2200 with an external battery (or any other standard USB power source for that matter). Please note, though, that this cable will no longer be compatible with most of your other micro USB devices. For example, even though I used a spare Blackberry cable that charged my Blackberry perfectly fine before the modification, it no longer charges my Blackberry. Thus, this cable is a dedicated Mifi 2200 charging cable. I labeled mine to that effect so I wouldn't forget in the future.

 

Hope this helps anyone that is as frustrated by the charging idiosyncracies of the Mifi 2200 as I was. Thanks, mikebob, for the research into this problem that has presented a very workable solution.

 

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Re: MiFi and Charging
MrElvey
Enthusiast - Level 2

Not true.  Mine doesn't turn itself back on if I use the supplied charger, and turn if off after plugging it in. I may have to do it twice or hold the button down for half a second before letting go, but not more than that.  I'm assuming this old thread is about the Verizon MiFi 2200 (there are so many now...)

It's only if I use something else to try and charge it that I find it will always turn itself back on - such as any of the half dozen USB car or wall chargers I have tried. 

On the other hand I had a Virgin MiFi 2200, and it would turn itself on no matter what, so it's probably software or version dependent.

I'm looking for a charger for my car that, unlike the ones I've tried so far, will work well.

  • allow me to shut it off while it's being charged
  • put out enough power that it can charge the MiFi while in use...
  • be available for < $5 or so

Extra batteries are cheap now ($4 at amazon), so I may just go that route - buy 3 or 4...

And yeah, I know tis is an old thread...

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