[Nexus 4 Accessories] setzer715:
Found this in my search for portable storage. RavPower WiFi Disk/SDCard Reader. Has good reviews on Amazon and Newegg (note 1 of the 2 reviews is for the wrong product on Newegg). Has a 3000mah battery which can be used for self power or to charge you phone. Has an SDCard slot and USB slot which is compatible with both Thumb Drives and External Hard Drives (NOTE: Reviews state it will work with SOME HD's, ones that require lower power). Thing is only $60!!! :D I plan to get one. Check it out!

Amazon

or

Newegg

Only thing I don't see in the specs is max size SD. Trying to research now.

UPDATE! RavPower emailed me back about capacity. This reader can handle up to a 128Gb SDCard.

UPDATE - REVIEW This is preliminary just to get something out there. Will update as I test more.

Size & Weight: The size of device is about the same as the Nexus, slightly wider yet slightly shorter and slightly thicker. I do not find it too big at all but of course I purchased this for travel and not every day use. If your looking for something tiny to carry in your pocket then you might want to look at the PQI as mentioned below. The weight is very light, lighter than the phone.

Design: The box itself has a pleasing design, will finished corners, Icons, LEDs, everything is very nice considering the much lower price than anything else on the market. Build seems solid. It is all plastic, but still solid.

Setup: It is very easy to setup. Simply press the power button and it will power up. This part does take a little time. You have to wait for both RW and WiFi LED's to go solid Blue before you can connect to the device. To connect to the device you need the Application available in the Play Store locate here. It is called MobileFun (Note: search for MobileFun as one work, not 2. If you search as 2 words you won't fine it in the store). Once you have the app, you simply connect to the device via WiFi, launch the app and your off. Note: Setting up WiFi Bridge is under Settings.

USB Interface: This seems to work flawlessly. I tested it using a Micro SDCard Adapter (with a Sandisk 64Gb Class 10 UHS-1 card), a 32GB USB 3.0 Jump Drive and my USB 3.0 external Hard Drive (Orico case with WD Black 500GB drive). All 3 connect and I am able to view/access files on the drives. If you have a External Hard Drive that requires a 2nd power source it will not work for you. PLEASE NOTE: With my SDCard Reader if I had it plugged in with the device off it would erase the card. This did not happen with my Jump Drive or Hard Drive. When you plug into the USB port with the device off it provides a 5V output for charging external device. My guess is this caused my SDCard to be wiped. So a word of caution, unplug your data drive BEFORE you power it off.

SDCard Interface: I ran into issues with one of my SDCards. My Sandisk 64Gb Micro SDCard would lose formatting every time I used it in this port. NOTE: It is a standard SD slot, an adapter is required for Micro SD. I cannot figure out what is causing this. It does not happen with any of my other SD Cards. Tested with A-Data 16GB Class 6, Partriot 32Gb Class 6, Samsung 8Gb Class 2 and Kingston 8Gb Class 4. All 4 of those cards function perfectly. All of my cards are Micro SD. I apologize, I do not own a standard SD Card to test with that.

Read/Write Speeds: Still testing this, will update once finished.

Movie Performance: All of my movies are H.264 with Variable Bit Rates. Most are .mkv but some are .avi or .mp4. I test all 3 packages in both 720P and 1080P. I used VLC Player (with Hardware Acceleration off). I streamed from the USB port only (as I do not have an SDCard) but I did stream from 3 different source, Hard Drive, Jump Drive and Micro SD Card reader. I had zero issues streaming movies. All played smoothly with no hick ups. NOTE: I am running CM10.1 with Faux Kernel. When setting up Faux clock for battery life playing these movies would not work. Audio would not line up and it would be choppy/pixelated. Setting Faux Clock to performance settings everything was smooth.

WiFi Bridge: This was unfortunately a little bit of a let down, at least on the performance side. WiFi Bridge does seem to work perfectly fine. I never had an issue connecting the device to my home WiFi nor using the internet through the device. The let down part is in performance. Speed test while directly connected to my Router are 20+Mbps consistently. Speeds while bridged through the RavPower varied from 2.5Mbps-6.5Mbps. It severely hampered speeds. Good news is that it still worked fine for most tasks, bad news is if you want to download a large file while streaming music it will slow your speeds.

Battery: I was able to stream 2 complete movies (1 at 1.5 hours long and 1 at 2 hours long). After I streamed 2 movies and my phone was almost dead there was enough juice left in the device to charge my phone up an additional 30%. The purpose of this test was to simulate travel, say on a plane. I could watch 2 movies and give my phone a little extra battery boost for when landing.

I apologize, I did not test music steaming, I would imagine it would use less power. But if it did use the same power you could stream music for 4 hours and charge your phone a little afterwards. Or, you could most likely stream for 5+ hours if you didn't need to charge your phone.

Recharge time from completely dead is unknown yet. I just killed it completely this morning, it is charging now. Will update this once complete.

File Transfer: This portion is still under testing. Will update.

Recommendation: YES. Note: If you already have an external hard drive (that does not need a second power source), jump drive or SD Card for data storage and just need something to access them I highly recommend this device. If you do not you may want to look into a wireless Hard Drive (at a much higher cost) as you can carry much more space with you. I.E. Seagate GoFlex with 500Gb or 1Tb drive. But if you don't need that much space you can get this device plus a 64Gb SDCard for $100 total, or $160 total with a 128GB SDCard/Jump Drive.

A few pictures next to the N4: