Thanks I think I found them - New 20C MaxAmps Lipo 4000HV 5S 18.5V Pack

But I´m still not sure - Do I need 2 of those ? won´t that give me a lot of volts ? 1 seems to give me decent volts but less runtime ?? to be true - I´m confused as hell :-)

And can these packs take the amps from my system ?

Please help here :-)