Mike, I suspect it varies with the brand of supply some are better than others, I use mine for running a computerized Hyperion charger for RC NiCad Lipo cells etc , its a cheap source of 12v at about 7 amps, I also use it to charge 20v battery packs for my workshop hand tools, the Hyperion gives a much better charge and full control of all the options, and can be displayed on a graph on your pc, way better than the rubbish chargers supplied with the tools