Pirl Charger 4x2.7A usb


Official specifications: This is a pre-release model, I got it from the developer (It is supposed to launch on Kickstarter in April 2018).
Being a prerelease model there was no box or accessories, I do not know if any will be included on Kickstarter.


The top and bottom is aluminium.



The box is built from layers of circuit board.




There is an indicator for each usb output, it is lit when it is delivering power and red if there is a fault.
The display shows total output power and there is a button beside it to adjust brightness of the display: off, low, medium, high.



Rating is 2.7A and overload protection trips at 2.8A, this is fine. The above curve is done at minimum input voltage.


Minimum voltage in a car.
The output voltage will increase with load, but it hits maximum increase at around 0.8A, then dropping output voltage at higher current is mostly due to connection and cable resistance.


Maximum voltage in a car.


Maximum rated input voltage.
There is not much different on the output with varying input voltage.



All outputs with maximum input voltage.


Input current will depend on input voltage, at this low load it can maintain output voltage at slightly lower than rated minimum voltage.



At full power it need 7V input to maintain output voltage.


Testing with all outputs at the same time.
Efficiency is slightly better than my curve shows, I have some looses in the cables and connectors.


Running 1 hour at 10.8A, display on charger shows 51 Watt (It was more like 53 Watt).
The temperature photos below are taken between 30 minutes and 60 minutes into the one hour test.


M1: 60,5C, HS1: 75,9C
With an aluminium top the temperature is fairly uniform, notice the input cable it is hot due to power loss in it and the connector.


HS1: 83,4C
At full power the bottom gets very hot (In real usage this power level will seldom or never be reached).


M1: 99,4C, M2: 98,1C, M3: 83,9C, HS1: 100,7C
After the above boring pictures, I did a test more with it open. 100C may sound bad, but the chips are rated for 150C inside, i.e. it is not too hot for the chips.


Noise is 11mV rms and 83mVpp


Noise is 10mV rms and 107mVpp


Noise is 3mV rms and 57mVpp


Noise is 3mV rms and 58mVpp

Noise is 2mV rms and 58mVpp


Noise is 8mV rms and 94mVpp, all tests show very low noise.

Tear down


Four screws and it was open.


The top has light pipes for all the indicators.


At the input is a high current power mos (RS1E200) and a sense resistor (R010) with a current sense chip (Probably ZXCT1022). For showing power is a microprocessor (ATTINY84A) with its own power supply chip (Maybe TPS715).
Each channel has a buck converter (AP65453) and a usb charge controller chip (TPS2549) that handles increasing voltage, protocol and overcurrent. The is also a small chip, I believe it is a voltage monitor (Maybe X6101 series). There is both a white and a red led for each channel (No multicolor led).


DSC_6655 DSC_6657


Sorry, no pictures from the bottom, the circuit board and the bottom aluminium plate would not easily part.


This is a very powerful usb charger, has auto coding, very low noise and individual port protection. The high temperature at full load is not really an issue, no standard usb devices will get it that hot.
I like a display showing output current or in this case output power (The processor must be doing some math with the sense resistor on the input).
The question is where to use it? In the car with a cable to the car battery, in the house with a external mains power supply (Sadly it cannot be used with a typical laptop supply).

I will rate it as a good usb charger.


The charger was supplied by pirlcharger for review.

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