Read about both here -

http://media.hyperion.hk/dn/eos/


Basically, the Net3-AD is an AC/DC powered moderate powered charger. Charger power output on AC is 90watts with a 20amp max charge rate. The power output will substantially limit actual charge current (if were trying to charge a 4S lipo at 20amps, charger would limit this to 90w/16.8v = 5.4amps, so its not as great a it sounds uinless you're charging low voltage, 2S lipos). It will charge 150watts running on DC power.

The Net3 is a DC powered charger, it requires a separate power supply. This is a more powerful charger having 250watts of charger output power as long as the power supply is adequate. It also has a max charge rate of 20amps, but with the 250watts, that 20amps is more useable than with the AD. You will need PS to run the Net3 charger.