Yeah I've got one of those. I tried pumping up my gun with it running off a NiCD drill battery. It made a lot of noise but wouldn't pump up. I assume the current draw was too high for the batteries. You can get those cheap at bunnings, I saw a transparent blue one today.
Thanks for the sprinkler valve pressure tip. I wasn't sure about those ratings. The plastic is really, really thick though so I assumed it could handle a fair bit.