To first judge the performance of the NuPower 60W USB-C power adapter I tested it out by charging a Nexus 5X which comes with a USB Type-C charging port. Over the course of several nights I observed the charging rate of the stock LG charger. With this charger we typically saw about a 1% increase in capacity per minute. The lowest we saw was 0.93%/min and the highest was 1.09%/min. I assume some of this variation is due to apps running in the background and during some of the tests we did get some text messages so the phone wasn't completely idle. Below is a screen capture showing a fairly typical charge rate of 1%/min.
Over the next few days I did the same thing but with the NewerTech NuPower delivering the charge. Surprisingly this charger was able to charge the Nexus 5X anywhere from 1.1%/min to a high of 1.18%/min. Below are two screen caps showing the phones charge at 7:06 to be 42%, then at 7:48 is was 88%, this is a gain of 46% in capacity in just 42 minutes. To rule out an issue with the stock chargers cable I used that with the NewerTech NuPower and found no difference in charging speeds.
Based on these observed charging rates we were able to decrease typical charging times by about 10% all without creating any noticeable heat in the NuPower device or the Nexus 5X.
Next up was testing the standard USB Type-A port to charge a Moto G3. Using a micro USB cable that came with the OEM charger I saw anywhere from 0.71-0.74%/min as can be seen in the screen capture below. While this is considerably slower than the USB Type-C results we saw previously, this is actually better than the OEM charger. The best rate I was able to get out of the OEM charger was 0.61%/min and in the screen capture below it is more like 0.56%/min. So given these observed charge rates I would expect the NuPower to recharge the Moto G3 about 20 minutes faster after a typical day's use.
I also did a test with both the Nexus 5X and Moto G3 connected. In this test both devices were less than 45% battery charge remaining and I saw the same charging rates noted above. I did not notice any heat issues with the NuPower or the devices themselves during the entire charge cycle.