Hi
Yes it is two cell (7.4v) 20c is the disharge rate,5c is the maximum charge rate
which means 5times the capacity which is 4000mah x5=20 amps
If you charge at this im not sure how long it would last
i personally only charge @2c which would be 8 amps
but if youve only got one,and you pushed for time
you might have to charge higher
HTH
