USB battery box 6x18650 Qidian


I got this box from fasttech.

Official specifications

How does it look

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I got the box in a retail package, labeled in Chinese (I suppose).


Because it is for 6 batteries, the box is fairly long.


The box has 3 output, two USB and on DC connector output with selectable voltage (5V/9V/12V).
The input is a also a DC connector.
The DC output connector is outer 4 mm and inner 1.6 mm, 11mm long.


The leds has a couple of functions: they show selected output voltage and battery charge state.


The switch is not a on/off switch as labeled, but a auto/manual power off switch.
In the off position the box must be manually turned off, in the on position it will turn off when load is removed.

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It is a bit difficult to load the box with 6 batteries, due to the pressure from the 6 springs, the minus rail has a tendency to slide up.
Due to this it is best to use unprotected flat top batteries.


Removing two screws and it is possible to remove the electronic. There are two push button on the electronic board, not only the one on the outside of the box. There is also a reset switch, that is used to reconnected the batteries when they are replaced (A charger will also do that).

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The 5 volt output is rated for 2A, but does not turn off, even at 4A. At 2A and below the output voltage is within specifications.


The 9V output is rated at 1.5A and does easily deliver that.


12V output is only rated for 1A, but again it can deliver considerable more.


The sweep looked nice, what about constant load? Here I have tested at 2A and it hold the 5 volt output voltage for nearly 6 hours.
It also has a good efficiency for a 2A output.


With 9 volt and 1.5A the DC output can hold 9 volt for more than 3 hours, but it does not turn off when the batteries are low!
At 220 minutes the output voltage drops down to 3 volt and it continues to supply power at 3 volt and 0.5A, until the battery voltage is down to about 2.5 volt, where the battery is disconnected.
The current draw might look huge at 5A, but with 6 batteries it is a light load for the batteries.
Because the voltage drops down to 2.5 volt, it is best to use Panasonic 2900/3100/3400 mAh batteries, that are rated for discharge down to 2.5 volt.


With 12 volt and 1A the time is around 4 hours. Again it does not turn on when the batteries are low.


With a single battery the efficiency is above 90% and it turns off the usb output at 3 volt.


3400mAh gives a bit extra runtime.


2600mAh gives a bit less runtime.


The output noise is very low on this box, even at 2A (27mV).


At 0.5A it is even lower (9mV).


9 volt does have more noise, but it is still very good (81mV).


12 volt is nearly the same as 9 volt (74mV).


When testing charging I am using a big power supply with enough current, but the box would not charge with the rated 2A current.
It took 12.5h to charge all 6 batteries.


But it can charge faster, if I uses a cheaper power supply. To simulate that, I added 0.1 ohm in series with the charge input and as can be seen it now chargers at 2A, most of the time. The charger time is reduced to 10 hour.


This box has a very good converter, that can deliver a lot of current with little noise. I am not that impressed with the constant power on the DC output, I would have prefered it turned off like the USB output.
The on/off (auto/manual) switch is a good idea, but the marking is useless.
If you need this amount of energy or the higher voltage, the box is good, but for most usage I will prefer a smaller box.


Read more about how I test USB power supplies and chargers