I just received the unit a couple of weeks ago. Canada Post is really slow when it comes to packages from China. I did do a few test at home. I was able to run my A129 duo for over 60 hours continuously, 6 hours more in buffered parking mode. My USB tester shows around 31,000mAh or 101Wh.
To my surprise, it came with a charger, 12V, 6A with a noisy fan in a very cheesy box and a jumper cable on a EC3 connector with a diode pack. The unit draws 5A initially with flat batteries and settles to 3.5A in a few minutes, and it takes about 5 hours to fully charge the unit.
There is a EC3 connector on the box and a capacity meter that is directly connected to the battery. The 12V cigarette lighter output, binding posts and 2.1mm barrel connector goes through the BMC board.
Cannot tell what kind of batteries and capacity they are because it is shrink wrapped. But can confirm that they are LifePo4 batteries from the discharge voltage.
I would give the build quality a 5 out of 10. When I have more time I will redo the wiring and put heat shrink on all the soldered connections. Here are a couple of pictures of the unit and of the capacity meter, I had to set it to LifePo4 because it came set to lead acid giving me wrong capacity readings.