Not a hub, but a 4 port wall wart.
Unless the hub is externally powered, it's likely not going to provide enough power to charge more than one at a time anyway. PC specs define the USB2 port as 5 volt - not problem there - and about 500 mA. And ego charger can go as high at 450 (well, the only ones I've seen), so one would top it out.
Over driving the port or hub could be catastrophic to your PC. That could be from too many devices on the hub, or a failure in either the charger or battery.