Those are not the QR Codes from the battery manufacturers. The real REPT QR code is under that black top cover by the negative terminal etched into the case. The QR Code will be scratched out but with luck there will be some numbers. Mine said REPT 3.20V 704Wh - a bit of math will give you the...
That is only a 20 Amp unit and requires a dc supply. I have modified a mains PSU 60 Amp 5 Volt unit to 3.65V by replacing the 1K pot with a 5K. You will need to measure volts and amps. I suggest a non contact ammeter to avoid volt drop. Good practice says the volt sensing should be brought...
The original post concerned the PSU charging voltage dropping lower than the no load set point. You are taking 10.3 Amps from a 10 Amp supply. It is hardly surprising the PSU is in current limit and the voltage has dropped. That is how CC charging works. You are getting more than you paid for ...