Why does the black model say 36W and the white model say 40W? Is that an error, or is there really a difference between the two?
A: Yes there really is a difference. The white one has 4 ports all of which utilize iSmart technology. Each port is able to output at up to 2.4A but not more than 8A total at one time. You can plug 4 tablets in at one time and still achieve a charging input of 2A on all four devices at one time. It will not do 2.4A on… see more Yes there really is a difference. The white one has 4 ports all of which utilize iSmart technology. Each port is able to output at up to 2.4A but not more than 8A total at one time. You can plug 4 tablets in at one time and still achieve a charging input of 2A on all four devices at one time. It will not do 2.4A on all four in this case because it maxes out at 8A no matter what.So it will break up the 4 ports into a total of 8A giving each device as close to it's max input as it can get without going over 8A total. The iSmart technology automatically detects your plugged in devices maximum input capacity and begins charging the device at that speed. So you don't have to worry about frying anything out or overcharge. It also ensures the fastest possible charge time. This one is a 40W charging unit. The black one is a 36W and is also a 4 port but only 2 of those 4 ports have iSmart technology that will charge at up to 2.4 A. The other 2 ports are just standard ports that max charge at 1.2A no matter how many devices are connected or what the devices max input speed is. Standard ports are usually used for smaller capacity devices such as cell phones which have a typical input of around 1.2A give or take a little. Tablets are a good example of a device that can input at a much faster rate such as the 2.4A. These 2 standard ports also are unable to detect on their own what your devices max input is. With both models being offered at the same price as of today i would definitely go with the white because it is capable of so much more, including quickest possible charge time. Even if you know for sure all your devices require only 1.2A input max, the white will charge them at that input. However if you should acquire devices with higher input max later your charging unit will still be up to par and ready to meet the criteria. I hope this helped answer your question. Have a wonderful day!! see less
- See more at: http://www.ravpower.com/40w-4-port-usb-wall-charger-black.html#sthash.hYo3aD3o.dpuf