I only tested at 5V but it put out 3A for the life of the battery! the quality of the 3D print was decent, a bit warped but totally functional the design is pretty good, could probably be more compact, but I really wish the USB jack had some more protection, it might get damaged in my tool-bag. I've looked at all the options on the web and this is the best. an excellent addition to the huge variety of ryobi 18v tools! FYI I also use my ryobi batteries to run LED lighting projects for festivals and other things with a 10A 12v adapter I made, and have been dreaming of an e-bike build :) thanks for making this! PS there was no documentation and no communication needed for my order, but I could not leave those ratings blank or N/A (fix it tindie!) so I put 5 stars.