Wednesday, January 22, 2014

Product review: Sabrent 3-Port USB Portable Charging Station


Sabrent charger has 3 ports (two on top, one on the side) and AC cord which is 56 inches long and ends with a regular small AC plug. I like corded USB chargers because they tape up only one slot on any power strip and the long cord gives me a lot of flexibility of where to place it. The 3 ports are labelled: 1A, 1A, 2A. I tested Sabrent 3 port 3 Amps Charger with Samsung Galaxy 7.7 Tablet (ICS 4.0.4), Samsung Galaxy Nexus cell phone (JellyBean 4.2.2), iPadMini, and SanDisk Sansa Clip+ player.

I own several wall chargers and power bricks and 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 results as the numbers speak for the performance of each unit. To test Sabrent 3 port charger I ran a large number of tests using 3 mobile devices on each of 4 ports. I also tested charging the tablet and the phone at the same time. For those who are interested in the details I am including them at the end of this review. To summarize the results of the tests I can say that its performance falls in the middle of the pack among the chargers I tested over the last year. Overall I like this charging station because it performed well and has extras that make it convinient to use: on/off switch and a long cord with a small plug.

➨ How I tested this wall charger:
======================

I have been testing various chargers for a long time, and people often ask me why results differ so much from charger to charger and often port to port. The results are different because they are affected by a number of factors. To help with a numerical explanation of the differences I began using a USB current monitor which 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 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 Nexus Phone
--------------------------
Port 1A (top): AC ----- 7% change in charge in 10 minutes
Port 1A (top): current monitor: ~~~~~ 0.94A and 5.08V

Port 1A (side): AC ----- 5% change in charge in 10 minutes
Port 1A (side): current monitor: ~~~~~ 0.84A and 5.09V

Port 2A:------ AC ----- 6% change in charge in 10 minutes
Port 2A: current monitor: ~~~~~ 0.90A and 5.08V

✔ Samsung Galaxy Tablet 7.7
--------------------------
Port 1A (top): AC ----- 3% change in charge in 10 minutes
Port 1A (top): current monitor: ~~~~~ 1.14A and 5.06V

Port 1A (side): AC ----- 2% change in charge in 10 minutes
Port 1A (side): current monitor: ~~~~~ 0.86A and 5.06V

Port 2A:------ AC ----- 3% change in charge in 10 minutes
Port 2A: current monitor: ~~~~~ 1.19A and 5.06V

✔ iPad Mini
--------------------------
Port 1A (top): AC ----- 3% change in charge in 10 minutes
Port 1A (top): current monitor: ~~~~~ 0.93A and 5.08V

Port 1A (side): AC ----- 1% change in charge in 10 minutes
Port 1A (side): current monitor: ~~~~~ 0.93A and 5.07V

Port 2A:------ AC ----- 1% change in charge in 10 minutes
Port 2A: current monitor: ~~~~~ 0.93A and 5.08V

✔ Samsung Galaxy Tablet & Samsung Galaxy Nexus Phone at the same time
--------------
Port 1A (top): AC ----- 2% change in charge in 10 minutes (Galaxy tablet)
Port 1A (top): current monitor: ~~~~~ 0.82A and 5.08V (Galaxy tablet)

Port 2A:------ AC ----- 4% change in charge in 10 minutes (Nexus phone)
Port 2A: current monitor: ~~~~~ 0.82A and 5.08V (Nexus phone)

The MP3 player worked on all ports.

To summarize all three ports worked. Overall I like this charging station because it performed respectably in my tests, small plug takes up just one slot on the power strip, long cord gives me flexibility in where I put it, and on/off switch allows me to save power.

You can find it on Amazon by following this link.



Ali Julia review ★★★★★

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