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Tuesday, January 14, 2014

Product review: TopG Smart Mini Dual USB Car Charger 5V 3.1Amp 15.5W Android Apple


Welcome my new favorite car charger - TopG Smart Mini Dual USB Car Charger. This little car charger is super fast. Over the last year I have tested quite a large number of chargers and this has been the fastest I have tested thus far. The speed of charging in a car charger is quite important to us because we use Nexus 7 for navigation. If the charger cannot keep up with a power hungry Sygic nav app during a long trip we are in trouble as we have grown totally dependent on GPS taking us places.

TopG Dual USB Car charger is compact (1.2" x 2.4") and provides up to 3.1Amps the combined power between two USB slots. The slots are labelled 1A and 2.1A. The front of the panel lights up to indicate that the charger is working. It fit the car port very firmly and did not get dislodged even on rough roads.

For those who are interested in detail of how I tested this charger I am including them below.

➨ How I tested this car 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 Nexus Phone
Port 2.1A: 10 minute test: ~~~~~~ AC rate ~~~ 11% in 10 minutes (charging cable)
Port 2.1A: current monitor: ~~~~~ 1.02A and 5.14V (charging cable)

Port 1A: 10 minute test: ~~~~~~~~ AC rate ~~~ 10% in 10 minutes (charging cable)
Port 1A: current monitor: ~~~~~~~ 0.98A and 5.14V (charging cable)

I received this charger from the manufacturer for an honest review be it positive or negative. I like its compact size and fast charging.

You can find it on Amazon by following this link.

Ali Julia review ★★★★★

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