Mobility Digest Review: Kensington Pocket Battery for Smartphones
If you’re looking for a simple way to charge most of your mobile gadgets, the Kensington Pocket Battery might be for you. As you can see from the image, it packs both micro and mini USB connectors(both of which can be used simultaneously) for charging your electronics. The underside sports a standard USB connector for charging the battery itself. The Lithium Polymer battery has a quoted capacity of 1200mAh(see below for further elaboration). Output is rated at 5V and up to 1A. Total weight is 1.76oz. The unit retails for $39.99 but I managed to pick one up from Amazon for $13. The price has since gone up to $20.
Physically the battery is larger than internal batteries of similar capacities. But you have to keep in mind that there are charge controllers and converters inside to make this thing compatible to a variety of devices. All in all, it’s a manageable size and the weight is very light. There are two LEDs located on the front of the battery. A green one for when the battery is above 30% and red is displayed when it’s below 30%. The indicator lights are only turned on when you press the button located next to them. The case is covered in glossy plastic and becomes easily scuffed. On either side you will find a micro and mini USB cable tucked neatly into the case. They are firmly tucked away but still easily accessible, a good balance. On the underbelly is the full USB used for charging. You can plug it into any powered USB port for charging. The battery can still be used while charging, so you can hook up two devices to the battery while it’s charging and have all three devices charging at the same time from just 1 USB port.
Charging the battery from empty takes approximately 1 hour. To turn on the battery for charging, you must press the battery indicator button. After about 10 charging cycles it managed to boost my Dell Venue Pro’s battery from 14%(230mA) to a decent 63%(1024mA). I used the EM app to read the percentages and mA capacities(I should note that the full battery capacity reads as 1644mA in the app and not the 1400mA printed on the battery). That’s roughly an 800mA increase. Considering the Kensington battery is rated for 1200mAh I was slightly disappointed.
However, I noticed they never published the battery voltage used. With a little math(Watt-hours = Amp-hours * Voltage) I discovered that the only way the rated 1200mAh works with the math is if it’s paired with a 3.7V output. Since the actual output is stated as 5V(not sure how they increase the voltage on the battery as I’m not an electrical engineer) I recalculated the capacity by dividing the 4.44Watt-hours by the 5V output. This gave me a capacity of just 888mAh. This lines up almost perfectly with the charge I managed to squeeze out of the battery(the phone was on while charging). As I stated, I’m not an electrical engineer, so if anyone wants to correct me here please feel free to do so in the comments. I’m always eager to expand my knowledge!
Bottom line, with OEM batteries running around $50 a pop, if you can find this for under $20 it’s a steal. Even at $20 it’s a nice backup to have since it can juice any device with a micro or mini USB charging port.
Kensington Product Page
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Nice review. I just purchased a similar product (new Trent IMP880) but it has 8900mAh on amazon http://www.amazon.com/New-Trent-IMP880-External-Blackberry/dp/B002YFDRHW/ref=sr_1_1?ie=UTF8&qid=1305332767&sr=8-1
You can even get the IMP50D (5000 mAh) which is around $42 and still not shabby. Was in the market for these for 2 months and after reading reviews upon reviews, I finally settled on the above. So far it worked great and seemed well designed.
@James:
Forgot to mention, the IMP880 is $59 and with both device, you can charge two devices at a time.
@James: @James: whoa…that thing is massive…I was looking for something more portable and I didnt want to worry about bringing extra cables/adapters with me everywhere. Your model does offer more bang for the buck though
Dang James, that is huge. I use a DigiPower JS Dual, which has a fold out AC charger and two standard USB ports. Coupled with a 12″ USB to Micro USB cable I can walk around with phone and charger in my hand. It’s rated at 1700 mAh, with a rated output of 5.3V / 500mA. With the 500mA, I wouldn’t try charging two devices at once. I can continue to use my 1230 mAh Surround while charging and typically I will get a green light before it drains out. Measures about 2.25 x 3.75 x 0.75. Can find it at Amazon http://www.amazon.com/gp/product/B004DUMBQE/ref=pd_lpo_k2_dp_sr_2?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B003IHV326&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=136EHQ7KT9VQGZASY9J9 for $36.44.
I have another DigiPower 3000 mAh for very long days, that’s about the same size but uses a mini-USB for charging. These little things are indispensible
@Danny Lam: Yep. I have had it for about 3 weeks now and occasionally take it with me driving or just to have in case I run out of juice on my hd7. The good part of the New Trent is it charges a variety of devices and supposingly it is marketed towards the iCrowd but it works well with other devices. Lots of good reviews tho ..I was tempted for a while to get the 11000 or the 16000 mah by i.sound but I settled for the 8900mah which is actually pocketable.
@Jim Szymanski: Yours is actually not bad. However, I’m not sure if 1700mah justifies the price. I wanted something that can charge my phone say 2-3 times before calling it quit. I originally started looking for a solar charger and I ended up with a battery pack. For additional $5, you can get the New Trent IMP50D (5000 mah) and it has dual usb ports and I think it charges via a usb port as well.
@James: Understood. I really liked the fold out AC charger on this one so I can plug it in anywhere and wanted to avoid the multi-plug route as this was specific for my phone (although it will charge anything with a micro, mini or std USB). As noted, I can hold the phone and charger in my hand comfortably using the short cable. I tried a right angle USB cable but straight/straight worked best. Once I am fully charged, I plug it back into the wall and if I am down to 50% after a few hours (on a really busy day), the charger is ready to go again.
But good to see there are more choices out there. When I picked up these two DigiPower units last November I didn’t find many options in my web searches.
@James: I other neat feature i just discovered about the New Trent is if you disconnect the phone from the battery pack, after about 10-15 secs, it auto-power off. Also, when the device is fully charged, it shuts off as opposed to continuous charging.
what i like about the Kensington one is that the cables are built in, so no little bitty pieces to lose while on the go. just wish it had a little more capacity.