Friday, December 20, 2013

Product review: LOFTEK® EP4 4 Port USB Wall Charger Station

Loftek 4 port charger comes with a 44 inch cord and a regular sized plug. I was able to replace two dual chargers that took up three slots on my power strip with one regular size plug which is connected to this 4 port USB charger.  I am always running out of slots on my power strips so this charging station a big space saver for me.

The charger has two 5 volt 2.1 Amp ports and two 5 volt 1 Amp valts.

The unit's size is 4.5"L x 3.5"W x 1.25"H. It weights 8.2 oz (including the cord).

I charged my Galaxy Tablet on each of the slots and I measure the current with a current monitor to see what power is delivered on each port.  Results are pretty good and consistent!

➨ How I tested this charging station:

I have been testing 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 Tablet

Port 1: 5V ~ 2.1A ~~~ 10 minute test: ~~~~~~ AC rate ~~~ 4% in 10 minutes (charging cable)
Port 1: 5V ~ 2.1A ~~  current monitor: ~~~~~ 1.65A, 5.07V (charging cable)

Port 2: 5V ~ 2.1A ~~~ 10 minute test: ~~~~~~ AC rate ~~~ 4% in 10 minutes (charging cable)
Port 2: 5V ~ 2.1A ~~  current monitor: ~~~~~ 1.59A, 5.03V (charging cable)

Port 3: 5V ~ 1A ~~~~~ 10 minute test: ~~~~~~ AC rate ~~~ 4% in 10 minutes (charging cable)
Port 3: 5V ~ 1A ~~~~  current monitor: ~~~~~ 1.57A, 5.03V (charging cable)

Port 4: 5V ~ 1A ~~~~~ 10 minute test: ~~~~~~ AC rate ~~~ 4% in 10 minutes (charging cable)
Port 4: 5V ~ 1A ~~~~  current monitor: ~~~~~ 1.61A, 5.10V (charging cable)

I really like this charger.  It charges quickly and I like that it takes up just one slot on my power strip.

You can find it on Amazon by following this link.

Ali Julia review ★★★★★

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