Hey everyone, I picked up the Kmashi external battery pack that was featured here on Android Central, and thought I'd put it through the wringer. I have several external battery packs (because I like playing with them), and I like knowing how they behave before getting in a critical situation. The Kmashi caught my eye because it was bigger than all my other batteries, both physically and in capacity. When I say this thing is big, I mean BIG. As in you could use it as a personal defense weapon. I've got a couple 10,000 mAh external batteries, and they are downright slim in comparison. I'd give other chargers to my wife on trips, but I fear this one at a full 16 ounces would strain her purse. It is a decent looking cell that feels nice and resembles a book, so it gets points for being a well thought out design. I do wish it had a simple LED flashlight feature like some of my smaller cells though.
On the bright side, it is a well made device with a smart layout and better than typical status lights. The power/status button is easy to find, and having the input power port for recharging the battery pack at the top of the long side works very well for me. I also have to mention that the packaging and instructions are far better than what you get with other external batteries. In the box you get the battery, a welcome card, separate instructions (in English for the US and UK markets), and a short USB to micro-USB cable.
For the testing, I decided to do a simple real-world usage test instead of just lab results. Having a spreadsheet is nice, but just seeing what it will do can be more beneficial. I started with the Kmashi battery topped off, then charged the phone from it, then topped the Kmashi off again before starting the test. I just used the battery to charge the phone as needed, but I have to say that I got almost abusive with the phone itself, with marathon gaming sessions and falling asleep watching stupid YouTube videos. The phone is a daily driver, so it was also used for work email and movies and everything else. Average screen on time was about 5 hours per day, as documented by GSam battery monitor. On to the test!
Kamashi model K-MP836
Phone: HTC One Model M8 smartphone with 2,600 mAh battery.
Battery age and health of Kamashi unit: New, good.
Battery age and health of phone: 1 year, good.
Goal: Test endurance with external battery pack as the only source of power.
Usage Restrictions: None.
External battery reliably charges phone to 100%: Yes.
External battery disconnects after phone reaches 100%: No.
Behavior when external battery can no longer charge phone: Disconnect
Test begins: 11/21/2015
First charge Saturday night: 32 to 100% (68%)
Battery status after charge: 4 bars
Second charge Monday morning: 25 to 100% (75%)
Battery status after charge: 4 bars
Third charge, Monday night: 22 to 100% (78%)
Battery status after charge: 3 bars
Fourth charge, Tuesday night: 16 to 100% (84%)
Battery Status after charge: 2 bars
Fifth charge, Thursday morning: 21 to 96% (75%)
Battery Status after charge: 0 bars
Total actual charge = 380%, or 3.8 full charges.
During testing the external battery did not exhibit anything in terms of getting the slightest bit warm. The battery turns on automatically when the phone is plugged into it. There were no complications or misfires, and when the Kmashi battery was depleted, it simply turned off. I would be completely confident that this cell would perform without causing any problems. However, there is one shortcoming, and that is the number of charges for a cell of this size. A 15,000 mAh battery should be able to charge the 2,600 mAh battery in the test phone from 0 to 100% a total of 5.7 times. Instead, we got the equivalent of 3.8 full charges. I know the charge process is not 100% efficient on any device, but only getting 9,880 mAh delivered from a cell rated at 15,000 mAh was a slight letdown. However, I'm glad I made the purchase, and would buy one again in a heartbeat.
On the bright side, it is a well made device with a smart layout and better than typical status lights. The power/status button is easy to find, and having the input power port for recharging the battery pack at the top of the long side works very well for me. I also have to mention that the packaging and instructions are far better than what you get with other external batteries. In the box you get the battery, a welcome card, separate instructions (in English for the US and UK markets), and a short USB to micro-USB cable.
For the testing, I decided to do a simple real-world usage test instead of just lab results. Having a spreadsheet is nice, but just seeing what it will do can be more beneficial. I started with the Kmashi battery topped off, then charged the phone from it, then topped the Kmashi off again before starting the test. I just used the battery to charge the phone as needed, but I have to say that I got almost abusive with the phone itself, with marathon gaming sessions and falling asleep watching stupid YouTube videos. The phone is a daily driver, so it was also used for work email and movies and everything else. Average screen on time was about 5 hours per day, as documented by GSam battery monitor. On to the test!
Kamashi model K-MP836
Phone: HTC One Model M8 smartphone with 2,600 mAh battery.
Battery age and health of Kamashi unit: New, good.
Battery age and health of phone: 1 year, good.
Goal: Test endurance with external battery pack as the only source of power.
Usage Restrictions: None.
External battery reliably charges phone to 100%: Yes.
External battery disconnects after phone reaches 100%: No.
Behavior when external battery can no longer charge phone: Disconnect
Test begins: 11/21/2015
First charge Saturday night: 32 to 100% (68%)
Battery status after charge: 4 bars
Second charge Monday morning: 25 to 100% (75%)
Battery status after charge: 4 bars
Third charge, Monday night: 22 to 100% (78%)
Battery status after charge: 3 bars
Fourth charge, Tuesday night: 16 to 100% (84%)
Battery Status after charge: 2 bars
Fifth charge, Thursday morning: 21 to 96% (75%)
Battery Status after charge: 0 bars
Total actual charge = 380%, or 3.8 full charges.
During testing the external battery did not exhibit anything in terms of getting the slightest bit warm. The battery turns on automatically when the phone is plugged into it. There were no complications or misfires, and when the Kmashi battery was depleted, it simply turned off. I would be completely confident that this cell would perform without causing any problems. However, there is one shortcoming, and that is the number of charges for a cell of this size. A 15,000 mAh battery should be able to charge the 2,600 mAh battery in the test phone from 0 to 100% a total of 5.7 times. Instead, we got the equivalent of 3.8 full charges. I know the charge process is not 100% efficient on any device, but only getting 9,880 mAh delivered from a cell rated at 15,000 mAh was a slight letdown. However, I'm glad I made the purchase, and would buy one again in a heartbeat.
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