Popular Mobile Batteries on Amazon Japan, Do they really work? We put the 10,000mAh capacity Batteries to the test
As the Smartphone became the universal cellular device, users came to realize the failing battery life their devices offered. Naturally the demand for a solution was inevitable; the emergence of the mobile battery. There are various types of mobile batteries currently on the market. Some mobile batteries released even exceed 10,000mAh. If you were to search mobile batteries on Amazon, the top selling mobile batteries are the ones with the highest capacity. Some being cheaper than others might make someone wonder, do they really work? It is only natural to assume the worst.
So let’s do the test!
We tested 5 products: 3 best-selling models from Amazon Japan and 2 cheaper large capacity models from retail stores in Akihabara (8,000mAh +). Is the Amazon ranking really accurate? Or is it the same if you purchase a cheaper model from retail stores?
We put these products to the ultimate test, so you can choose the right battery!
[Products we tested]
・Product 1 “cheero Power Plus 3″ 13,400mAh（Very popular on Amazon）
・Product 2 “GSK mobile battery” 12,000mAh（Very popular on Amazon）
・Product 3 “Anker Astro M3″ 13,000mAh（Very popular on Amazon）
・Product 4 “KMB-88 Series” 8,800mAh（Extremely cheap one from retail store）
・Product 5 “POWER BANK” 9,000mAh（Extremely cheap one from retail store）
[Test 1 Stress Test]
How much electricity (A) can they provide? It is better having a bigger current capacity. However, even if it has a high current capacity, there is a limit to the amount of electricity that can be used to charge a device. If the current is too big, it will just take up space. The electrical current should be the same or more than the charging device capacity. For example, if there is a 1.0A and a 2.0A, the ideal would be 3.0A or more.
[Test 2 Capacity test]
How long can they supply 2A current? The longer they last, the bigger the capacity. There is a variance between the rating and the battery capacity due to the DC-DC converter efficiency of each device.
[Test 3 Taking it apart]
We examined the structure and parts of the batteries. Are there cheap parts? How is the wiring? Is the micro-USB connector firmly attached? Micro-USB connector are small and have a specific placement. If excess force is applied, the solder wear away and falls apart, making the parts loose.
The graph above shows the voltage discharge under load 2.5Ω（5V 2.0A). We kept a steady 2.0A current flowing from the battery to see the stability of the Voltage and how long it took to comes below 4.0V.
Product 1 “cheero Power Plus 3″（＝7.4V Battery type) had a stable voltage (a slight increase and decreasing variance) and was able to supply an electrical charge for a long time. However, the other devices (3.7V Battery type) had a much larger variance.
So, let’s get started!
[Product 1 cheero Power Plus 3 （13,400mAh） JPY \3,480]
Score ★★★★★（5 out of 5 points）
Results from the stress test
The voltage is stable up to 5A. Even supplying a high amount of current of 2.5A on each port, it stay stable.
Out of the 5 products we tested, this was the model with a series circuit battery (7.4V) (*). Output control (DC-DC converter) converts 7.4V to 5V. It stood strong against high voltage and yielded the most stable results. It can handle quick charges found in Apple devices with ease. The micro-USB connectors that came off easily was soldered in place using 4 solders and 2 through holes in the device. The strength was average. As long as you handle it in a gentle manner, the chances of the connector coming loose are significantly lower.
* About the series circuit: You need a 5.0V to charge your device. If you are using a 3.7V (voltage of 1 Li-Ion cell) battery, you would use a booster pack DC-DC converter. With a 7.4V series circuit battery, you would use a step down DC-DC converter to lower the voltage to 5.0V. The efficiency depends on how good the circuits are, but generally are easier and more efficient to step-down the voltage. However, when charging a 7.4V battery, you need to boost it from a 5.0; you would need 2 DC-DC converter circuits increasing your out of pocket expense.
[Product 3 【Amazon.co.jp limited product】Anker Astro M3（13,000mAh）JPY \3,499]
Score ★★★☆☆（3 out of 5 points）
This product enters the oscillated state under high stress. Inside the battery there is a booster to raise 3.7V circuits to 5V, but as soon as the circuit runs out of room, it becomes saturated and oscillated (use it near the limit). 4 solders for micro-USB, but the surface of the base copper is not big. I’d say medium strength.
[Hands down, our vote goes to “cheero Power Plus 3”!]
No wonder it’s the best-seller on Amazon Japan. Product 1 “cheero Power Plus 3″（13,400mAh *Measured capacity 8,374mAh）is JPY \3,480（Amazon price). It is not cheap, but it provides a stable supply of electricity and capacity. You can use it for quick charge on an Apple devices like iPhones. A most reliable mobile battery at a reasonable price, give it a try.