Sunday, February 16, 2014

Product review: OXA 3000mAh Perfume Ultrathin Mini Stylish Power Bank

The first thing I noticed about this power bank is how small and light it is. The OXA 3000mAh battery pack is 4.25" long, 1.5" tall, and 0.375" thick. I like its form factor. It weighs 2.6 oz. Because it is small and light I keep it in my purse as emergency power in case my phone dies. It comes with a strap, which I was able to hook to a carabineer inside my purse. It means I don't have to fish for it among the other stuff.

This power bank has one USB port. It comes with a charging cord and several charging tips: micro USB, munu USB, Apple connector among them.

The Amazon description mentions perfume smell. I did not detect any scent, which is a good thing. I really don't want my battery to smell.

I tested OXA 3000mAh external battery pack with Samsung Nexus phone, Samsung Galaxy Tablet and iPadMini. The battery very well charging the phone. It worked with the Galaxy tablet but a below average speed. It did not charge iPadMini at all (but kept it from discharging). So this power pack best suited for phones and MP3 players, which is reasonable given its capacity and size.

I own a number of external batteries and to compare them I run the same set on tests on each of them, so they can be compared to each other using "apples to apples" comparison. This set of tests allows me to provide unbiased comparisons between different external batteries. For those who are interested in the details of the tests I include the details below.

★ How I tested this battery pack

I use a USB current monitor and a charging test to test each port. The current monitor shows the voltage and the current flowing between the battery and the device.

The amount of energy transferred from the charger to the device is calculated by multiplying voltage and current. Most of the chargers are 5V devices and most devices show the voltage very close to 5V. The interesting number is the current as it varies from unit to unit and from port to port.

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 for Android devices 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 Nexus Phone
AC charging ----- 8% change in charge in 10 minutes
current monitor: ~~~~~ 0.93A and 4.79V

✔ Samsung Galaxy 7.7 Tablet
AC charging ----- 2% change in charge in 10 minutes
current monitor: ~~~~~ 0.88A and 4.81V

✔ iPadMini
AC charging ----- 0% change in charge in 10 minutes (did not charge but kept from discharging)
current monitor: ~~~~~ 0.93A and 4.79V

★ Summary
This pack showed very impressive performance with Nexus phone, it is not the best charger for the tablets which is not surprising given its capacity and size.

You can find it on Amazon by following this link

Ali Julia review ★★★★☆

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