I know I am a bit weird, that's a given. I stared using tanks when I got my DAV batts. I tried and tried to fill like the instructions said but lost more liquid then I kept! I have been filling my tanks by taking them off the bat and removing the drip tip. Then I push down on the drip tip end and pop the cartridge inside out a bit until I can angle it down to catch the top ring (where the drip tip goes) a quick push and the ring comes off and I can fill the tank in peace. Reasemble and Bob's your Uncle it's done with out a drop spilled. I know it sounds complicated but once you do it a few times it's really fast. Now have you found a better way to fill them?