I'm looking at buying the Hyperion 615i duo charger. Do I need to buy a seperate power supply for this charger? Also I plan on using this at the track so I will be charging at the track off my battery I take with me. Will this charger work on DC power? I plan on charging 5S 5000mah batteries. I don't want to take forever to charge them at the track. Thats why I was looking at this particular charger due to it's high output.