Does the jobAwsome chargerThe advertised and rated charge voltage these units are supposed to provide is not met by the units I purchased. The voltage rating on the unit label is 54.6V, and when I checked the output, with no load, the voltage was only 52.4V, so these chargers will not bring my Li-Ion batteries up to full charge. I checked the voltage with a calibrated FLUKE multi-meter, so I know my measurement is correct. The quality control at the Chinese factory is bad or non-existent...as usual. As an Electrical Engineer with Quality Assurance background, this is unacceptable. I will have to to pen the unit to see if there is an output voltage adjustment, and determine its range of adjustability...again, IF there is an adjustment. The ripple seemed acceptable, at just a few millivolts, but the DCV level is clearly not good. I would not mind a couple tenths of a volt off, but but 2.2V is too great a difference.Oh, and my supply AC voltage is good, in case they would try to blame the supply side. It is exactly 120VAC from a power conditioner, clean sine wave.Fan is a little on the loud side.When I first got this product it worked great charged my e-bike batteries up real fast . But as I used it more it eventually started charging at a slower and slower pace to the point where my cheap chargers were outpacing it in its charge time. Finally last night I was trying to use it ,it must overheat it and a capacitor blew because I heard snap crackle coming from inside the controller unplugged it.What can I say , this item charges my 48 volt batteries . Time will tell but I think I made a good choice.This machine replaces a competitor's cheaper 48V charger w/o cooling fan that gave out on me. This machine is built right and the cooling fan will extend the life I am sure. Came with some extra fuses, and a tool that appears to be a fuse puller/installer.This is a big upgrade from the cheap chargers that often come with ebikes, which don't have fuses and can damage or brick your battery. This charger has a fan, replacement fuses, and overall nice build. Worth the upgrade.