Saturday, January 18, 2014

Product review: ARCTIC Power Bank 4000 Ultra-Slim 2.0A Output 4000mAh Backup Battery/Charger

Artic 4000mAh battery is very compact. It is 2.125" wide, 4.5" long, and 0.375" thick. It weighs 3.9oz. It is small enough to carry with you without feeling like you have a brick in your purse or pocket.

The charger comes with 2 eight inch cables: 1 micro USB and 1 mini USB. True to its name the battery pack remained very cool even when it was charging my tablet. The "on" buttons looks like a second micro USB charging port. The little light within it does not stay on, so I took me a few seconds to find the switch the first time I wanted to turn it on. Since the light does not stay on all the time and there is no other charge level indicator it is hard to tell when the charger is out of juice without pressing on the button.

I tested this pack with Nexus Galaxy Phone and Galaxy 7.7 tablet with both a current monitor and using a 10 minute charging test. I always run these test so I can compare different chargers to each other based on the results of the same tests. This gives me an unbiased way of measuring how each external battery performs.

Summarizing the results I can say that it charged my phone extremely fast (among the fastest I have tested), but performed below average for my tablet. Given its capacity and size it is best suited for the use with the phone.
If you are interested in the details of the tests I am including them below.

➨ How I tested this battery pack:

To test this battery pack I used a current monitor. In addition to the current monitor I also used a 10 minute charging test which is less abstract than the measurements of current and voltage.

I have been testing chargers and batteries for a long time and people often ask me why results on different ports of the same unit or similar units are different. The results are different because they are affected by a number of factors. To help with a numerical explanation of a differences I began using a USB current monitor which shows the voltage and the current flowing between the battery and the device.

Most of the batteries are 5V devices and most devices show the voltage very close to 5V. If the voltage is higher it can damage a device and I will report higher than expected voltage if I see it. The intersting number is the current as it varies from port to port and from unit to unit. The amount of energy transferred from the charger to the device is calculated by multiplying voltage and current.

The current varies based on what the device requires and what battery provides. This communication happens using different protocols depending on OS. Newer Android OS versions have adapted their protocols to get better performance from ports aimed at Apple devices. An addition variable that effects performance is whether a data cable or charging cable is used to charge the device. The charging cables short the two data connections together (rendering them useless for data transfer), but this fools devices to see the cable as an AC power connection, and thus accept the higher current of the charging source.

The 10 minutes test consists of charging each mobile device on each port of the battery pack for 10 minutes and measure how much each unit was charge in that 10 minute period. Since the charging speed is non-linear I start charging each device from approximately the same charge level. I use Battery App by Elvison to determine how each device recognized the charging source. 'AC' status means the charging is at full charging rate. 'USB' status indicates charging at a lower charging rate. 'Discharging' status means that the charging rate is below the power that the device is consuming so it slows down the discharge rate but does not re-charge.

➨ Test Results:
✔ Samsung Galaxy 7.7 tablet
Charge at AC rate ~~~~~~ 2% change in charge in 10 minutes
Current monitor: ~~~ 1.07A, 5.07V

✔ Galaxy Nexus Phone
Charge at AC rate ~~~~~~ 8% change in charge in 10 minutes
Current monitor: ~~~ 0.97A, 5.07V

I found this external pack performed very well with the phone and I liked its compact size.

You can find it on Amazon by following this link.

Ali Julia review ★★★★★

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