Review: SHALLVIO USB-A USB-C 8.4VDC 4.0mm heated vest powerbank 68Wh $38

Amazon Affiliate Link: https://amzn.to/47Utyab Price as reviewed: $38 20000mAh Heated Vest Battery Pack – Compatible with 7.4V DC 4.0mm Heated Apparel & Most USB Heated Vests, Long-Lasting Power Bank for Up to 13H Warmth From the SHALLVIO Store This powerbank has a USB-C In/Out port for charging. It appears to default to 9 volts at 2 amps (18 watt) charging rate, even if the charger supports the 12 volt level. In my test it delivered 68 watt hours out of the USB-A port at 5 volts before reaching zero and shutting down. The powerbank never got hotter than around 80F (mostly in the power electronics, the battery cells stayed cooler) while discharging at 18 watts. I suspect that if you used the 8.4 volt 4mm plug to directly access the battery at it's native voltage you would get closer to the rated 76 watt hours of capacity by bypassing the voltage conversion circuitry energy losses.] It took 88 watt hours to recharge the powerbank over 6 hours. The claimed 20 Ah (20,000 mAh) capacity (w.r.t. a 3.8 volt Li Ion battery) would be 76 watt hours, and given the charging and discharging conversion losses, I feel that the rated capacity is correct based upon my discharge and charge tests. If you are drawing 5 volts out of the USB-A port, the USB-C port also shifts to delivering 5 volts. I saw 3 amps from the USB-A port and 1.5 amps from the USB-C port at the same time, so it can charge two devices at once, but not at different voltages. The button turns on the percentage charged display, and if you are discharging will also give an "amps out" or "amps in" display and the actual battery voltage if you click it a few more times. Overall this powerbank has the rated capacity, I've seen it work at at 5 and 9 volts (and my USB-C tester got it to export 12 volts at 1.67 amps, but I didn't see any of my devices use the 12 volt level) and meets its specifications. If your heated clothing uses a 4.0mm plug at around 8 volts, it is perfect for you. Even if you are just using it to power USB-A or USB-C powered devices, it works well, although the two ports can not do independent voltages, so it's best for charging a single device at a time.