I believe the input voltage for a CT1/2 head is about 450V. There is a third contact wire that I think is used to quench the flash capacitor dump in the pack after enough light is sensed by the head. It allows a faster recycle. The flash capacitor is in the pack, not the head on a Metz CT60
The dryfit sold for the ct60 pack is a speciallized contact type of Absorbed Glass Mat lead acid battery. Non speciallized AGM batteries are easier for me to find, and cost half as much, and recycle just fine.
I use conventional UPS style AGM batteries with theterminal tabs bent back in themselves to put the contact in the right place to meet the pack's contact fingers. I had to shave a couple of spacer ribs out of the bottom of the pack to let the somewhat taller battery fit. Be sure to write on the correct side of the battery so you don't put it in backwards.
I have used a 5V comupter p/s connected to the chassis of a dead dryfit to use this CT60 pack in the studio with no batteries. It worked quite well. Others from my past posting here on Metx CT60's have adapted golf cart batteries to feed their packs, and report they work fine as well.