Qi-Infinity™ Surface Pro 4 External Battery - 35,000 mAH Extended Pack for Windows Microsoft Tablet Surface Pro 1 2 3 4 & Surface Book - Includes 4 USB Ports, AC Adapter & Accessories in Bundle

TL;DR: Good product. Great battery. SP4 cable is not as heavy duty as it feels/seems. Purchase from Amazon for a hassle free experience. Will not charge low-drawing electronicsPros:* Good Battery* Small and light for its capacity* Comes with Surface Connector* 4 USB Ports!Cons:* Qi-Infinity claims there are 2 x QC2.0 Ports, but these ports did not quick charge a Samsung Note 4, Samsung S6, and Samsung S6 Edge - which are all QC2.0 compatible phones* Charging port for the PowerBank (the port to charge your PB) uses the same size barrel as the output port. This may cause confusion where people trying to charge their PowerBanks may accidentally plug into the output port instead. Not sure what would happen.* SP4 charge cable is not as heavy duty. Weakest point is where the cable meets the cable plug. Picture attached.* Will NOT charge small USB devices like my FitBit Charge HR since I believe the PowerBank doesn't detect a device connected if it just sips electricity when charging.Review (Updates are after initial review):I purchased this product directly from their website since Amazon stated that it was going to come after the holidays. After purchasing, I received a shipping confirmation six days after I purchased. After another week has gone by, I had to inquire about my purchase since I did not receive the Powerbank yet (asked for tracking number). I got a reply that day stating that they are checking the warehouse for the tracking number. Two days later, I get a tracking number and found it the item actually shipped that day. Makes me wonder what would've happened if I didn't inquire on it.. I received the Powerbank yesterday.Anyway, received the product and there were some things that surprised me. First, this comes with an AC adapter that charges your Powerbank and the Powerbank has a LED light that you can turn on and use as a flashlight. This features were not mentioned before but has been updated.The AC adapter also has a USB port for charging. It is a 2.0A charger, which is way better than the 1.0A USB charger the Surface Pro 4 AC adapter comes with (although the Surface charger is a LOT smaller). The AC adapter and all the cables that plug into it (110v cable and the Powerbank charging cable) are all white in color. Cable quality seems high. I did notice that the charging port and the 12v-15v port are of the same size. This means that you can connect the AC adapter to the output port of the PowerBank. Not sure what this will do, but I don't want to find out.The Powerbank also comes with 3 black cables:1 x USB (M) to USB Type C (M) for newer phones1 x USB (M) to Surface Pro 3/41 x USB (M) to Micro USB (M)All cables were high quality. There is a light that lights up on the Surface Pro cable, but this is to indicate that there is power in that cable as opposed to a charging / connected indicator like how the OEM Surface connector.As I have only had this Powerbank for one day, I haven't tested out it's capacity just yet. That will come later. The Powerbank came to me charged up and ready to go.I did notice that when I plug my Galaxy Note 4 into the QC charging port of the PowerBank, it does NOT say that I have plugged into a Quick Charger, like how it usually does when I plug into the Samsung AC adapter. Because of this reason, I have docked off one star. I will bring this up with tech support and see what they say.I have given it three stars since I have not tested the capacity of this battery just yet. I will update this review in a few days to give my impressions of the battery.But as for now, the non detection of a quick charge when plugged into a QC port was one of the features I was excited about, and I am disappointed to see that my phone is not detecting it.Update 12/27/2015:My review stands as a three star product after reviewing the product. I am considering returning this item back. Do note that this review is based on plugging into a Surface Pro 4 device.I have used my SP4 until the battery reported it hit around 8%. This is when I plugged in the PowerBank and let it do the charging. Here is the report:Day One - I wanted to test the battery when my Surface Pro was on and while I was using it. I plugged in the PowerBank and it detected and started charging. However, when the PowerBank got to around 50% (2 dots out of the 4 on the battery indicator), I noticed that the charge animation stopped and there was no charge icon on the battery. I look at the PowerBank and noticed it turned off! I turned it back on, and the plug icon came on, but Windows did not do the charging animation. When I mouse over the icon, it states, "Plugged, but not charging." I played with the connector for a little bit and at that point, it stayed on "Plugged, but not charging."Oh, the PowerBank charged my Note 4 today too, but it was not a QuickCharge. It took 5 hours to charge from drained battery (and yes, it was plugged into the QC port).Day One: The PowerBank made my SP4 last the whole day, with some qualms.Day Two: So, today, I made it a point to make sure the SP4 will plug into the PowerBank only when the SP4 is shut down (as opposed to sleep/hibernation/etc). I did not plug any other devices to the PowerBank today.The PowerBank fully charged my SP4 the first time, but the second time is different. The PowerBank turned off when the SP4 was only half charged. The PowerBank is blinking 2 LED lights indicating that the PowerBank is half capacity. I turn on my SP4 and there is no charge indicator in the battery icon. I turn on the PowerBank a few times, only to have it turn off again. I guess the PowerBank does not think anything is plugged into it?Day Two: PowerBank charged my SP4 to 100% the first time, but gave up charging the second time, even when the PowerBank reports half capacity.My theory (and this is only my theory), is that the "Smart Charging" algorithm. The same algorithm that knows how much voltage to send to your device, fails when the PowerBank's battery is not at full, or near full capacity. Once the PowerBank capacity reaches half way, it will not the SP4 anymore.Either that, or the LED battery indicator light is misreporting the capacity remaining in the PowerBank.Because of the fact that the PowerBank consistently turned off while trying to charge my SP4 a second time, I have to dock off a star. The reason for me buying this product is so my SP4 would charge up, worry free. But I feel it is a hassle to have to monitor whether or not the SP4 is charging or not, or if the PowerBank has turned off unexpectly. This is especially true, since the SP4 does not have a charging indicator while the SP4 is shut down.Maybe I got a defective unit? I will bring this up to Qi-Infinity and let you know, but for now, my review of this product is 3-stars until further notice.Update 1/9/2016:I am confirming that I received a defective unit. My new unit charges my SP4 even with two LED lights flashing. Because of this, I am upping my review to 4 stars, docking 1 star because of the lack of QC2.0 compatible. My new unit charges my SP4 a total of 2 times, while charging my SP4 about 70% on the 3rd charge. Because of the high number of times I can recharge my SP4, I decided that I am going to keep the item and not return it, even though this is not a USB quick charger.I did not buy this on Amazon, but rather from their direct website. Because of this, when I contacted them for a replacement, they wanted me to create a video of the fact that the PowerBank would not charge my SP4 when it was half full. They wanted a video of the PB not quick charging my Note 4, and they wanted a video of the PB turning off when it was suppose to charge at half capacity. My SP4 cable is also coming apart. I have used this cable exclusively since I wanted to follow up on this review and also test the battery out so I was heavily using the PB and the cable. The cable is already coming out of the connector head. I am going to bring this up to Qi-Infinity directly since I have picture (which I have included in this review).I thought that was waaaayyyyyy too much of a hassle and just decided to buy another one on Amazon, and that is the unit that I tested. This new item worked as expected, except for the fact that it does not quick charge any QC2.0 phones. I kept the unit for a few days, and returned it. Because of the proof that I need to furnish in returning the PB to Qi-Infinity, I STRONGLY recommend that you purchase this PowerBank from Amazon for their convenient return policy, if you decide to buy one of these.Update 2/25/2016Qi-Infinity replaced my defective SP4 cable by making me purchase their cable on Amazon and later refunded me the cost of the order. I just had to give them the invoice number. Nice and quick customer service for the cable issue.Also, one last note. The PowerBank only detects devices that are high drawing. That means, if you plug in a laptop, SP4, Kindle, anything that draws some power, the PowerBank will know that something is plugged in and stay on. However, I wanted to charge my FitBit and my Bluetooth headset, and after a minute, the USB ports on the PowerBank turned off. I think it's because the FitBit and Bluetooth headset only draws a little bit of power so the PowerBank doesn't think anything is connected for charging and turns itself off.Because of this, I have docked another star. This is only good for charging high draw electronics.

If we're just talking about the usability of the product, Qi Infinity is spot on. I Bought it specifically to charge a Surface Pro 4 while on the god and it does exactly that (Surface Pro 4 adapter included) so it's pretty good that way.The downsides:(a) They can do with a better written manual. I don't know what kind of English was used but honestly, for a company that distributes products internationally, they could have at least hired someone to type a better written manual. I'm not normally picky about this but frankly, you have to guess half the time what the manual is trying to say! It's that bad!(b) I don't know if it's charging most times. I plug it in and the manual says the LED lights automatically turn red if it's charging but it never does.It's always green for me until I press some buttons. So confusing.(c) My best guess is the product is useful only on a 1-charge basis. I say this because just to charge the product, there's a separate adapter altogether (similar to the ones you have for laptops--that big!!) so if you don't have space in your bag for your own laptop's charger, I doubt you'd have space for this battery's charger. It would have been nice if this came with a simple cable that you just plugged in direct to the socket. I know this is technology driven but hopefully at some point this aspect can be improved.

This battery is jam packed with so much goodness I don't know where to begin. Even the AC adapter is stellar. I have far too many batteries from various companies such as Bixpower, Anker, Goalzero, Intocircuit, Zerolemon, and many more. They all offer great battery solutions but this is THE battery to have for your Microsoft Surface devices, yet, it is useful for practically any modern netbook, smartphone, or laptop... even solar battery banks.Let's start with the premium AC to DC power adapter.. It provides 12-24 volts via auto voltage sensing circuitry. This means that whatever you plug it into, it will autodetect the voltage requirements and provide it. The AC adapter dimensions are 5.75" x 2.75" x .75" (LxWxH) which is a very portable formfactor. On one end it has a female receptacle for a 2-Slot nonpolarized AC power cord, and on the other end it has a proprietary female receptacle for the DC output cable. The DC cable has a common Male 5.5 x 2.5mm Barrel Connector for power output. This is important because there are countless barrel connector adapters on the market for whatever device you need to plug this AC adapter into. Additionally, it also has a USB port that provides 2.1amps of power. Using my DC Barrel Connector tips, this AC adapter powered my MacBook Pro, Surface Pro 3, and charged my Surface 3 via the USB port. My Surface Pro 3 and my Surface 3 are my daily computing units and this AC adapter powers both of them simultaneously by itself. This is the way the Surface Pro power adapters should have been designed in the first place. All cables can be disconnected for easy storage in a bag.Moving on to the battery. It is also a neat work of art. The battery is very small for the 35000mah of power it packs. It is definitely constructed with high-end 18500 cells. It measures 7.5" x 3.5" x 1" (LxWxH). Whenever it stops holding a charge, I'll crack it open and see how it ticks. It's all about the charge controller that is built into these battery units and this particular unit was truly designed for mobile computing. There are a lot of fancy names out there for charge capabilities but I like to measure by good old amps, volts, and watts. I'm not going to write the specifications sheet again, I'm just going to comment on the most impressive features to me. It has a USB port with autosensing voltage capability that can provide 40 watts at 5v, 9v, or 12v. I haven't seen one on the market yet that is designed this way besides Apple's USB-C AC charger. Anyways, it charged my 2015 macbook via USB-C cable at full speed. For those of you out there that complain about "fast charge" speeds. There truly isn't such a thing. It's all about battery quality, how the cells are wired, and how quickly the medium can absorb electrons. In short, if your 1 year old cellphone isn't "fast charging" anymore, replace the battery in your phone and try again. It is hardly ever the charger that is the issue. This battery has 2 female 2.5" barrel connectors for power input and output. Again, like the AC adapter, this is important to me because I can use barrel connector adapters to charge whatever I want. Even more importantly, I can daisy chain multiples of these units together to create a "bank" of batteries because the unit can charge while it is in use. This makes this battery a stellar candidate for solar applications.I'd also like to mention that this battery can power your surface pro 3/4 via the surface dock if you wish. Just purchase a proper 2.5" barrel adapter and away you go. The surface pro 3/4 power cable that ships with this battery is also stellar. It appears to be the exact same construct as the manufacturers. However, I prefer to use the Surface Dock.I plan to purchase several more of these. Qi-infinity definitely put their best into this product and it is worth the cost.

For the Surface pro, there's really no other option and this does the job very well. I'd give it 5 stars, but just some weeks of using it, the power cable for the Surface pro 4 stopped working. I had to get a replacement cable urgently from Amazon as I was travelling, which is very annoying. I previously ordered an Aukey power pack which only delivered a fraction of the advertised capacity, but this one has all the charge that it says it has. Wish it could be a bit lighter, but even as such it's one of the lightest for its capacity.