charging Samsung galaxy s4 ?

i have purchased galaxy S4 recently , but the problem i have is that the charger i got does not sit in the outlet in my home , but i already have an MP3 AC to USB adapter and its output is rated

5.5 V , 800 mA , can i use it to charge my S4 safely ? or it's better to charge it via PC USB port ?

here is a link to the adapter i have :

http://www.ecvv.com/product/2387173.html

this gives 5V , 700mA , while the one i have gives 5.5 V , 800 mA , is it ok ? this charger can be used for Li - ion batteries as said.

thanks