How many bolts per battery? Cost of batteries? Maybe I'll go poke around on the bosch site if you guys say it works that well.
Edit insert: What model full size bosch you guys using? I can't remember my model off the top of my head (not old) but the hammer blow rate seems pretty high, hard to imagine something smaller going faster. That might be an interesting spec to check out.
All I can say is our setup works for us, don't know that it's a whole lot better than others. People like the Fish seem to swear to the battery pack and extension cord. Whatever works and one is comfortable with I guess.
It's a pretty simple system really. Kind of a hybrid on the fifi approach, using the last lead bolt. Hopefully I can explain it adequately as people seem to sometimes get a little lost without seeing it in action.
First the drill has a custom made cover that can take the wear of sliding while being pulled up, or lowering. A little padding maybe as well to help protect it. I dislike any kind of pulley where the belayer winches it up to the leader, so it is pulled up by hand.
Two ropes, lead line and tag for the drill. The belayer alternates between active/passive on the ropes. At the top bolt: clip one draw for the lead line as normal. Clip a second draw for the drill (replaces fifi hook), pull an appropriate amount of tag line slack to get to the next stance and tie a knot. Clip the drill into the knot, then hang the tag line from the second draw with the knot against the biner on the up side - downside goes to the ground/belayer. The belayer can now pull the tag line tight holding the drill snugly against the biner (via knot and drill.) Belayer ties off tag line in taunt position. Leader climbs to next stance, as normal. At stance, take slack out of tag line and inform belayer ready for drill. Belayer ties off lead line (giant knot in front off ATC, Gri-gri, whatever). Belayer loosens tag line and allows the drill to be pulled up, keeping drill on belay in case it gets dropped (or leader decides they can't finish pulling and lowers it back down.) Once the leader has finished the hole and drill is on shoulder/harness (no drill belay needed anymore) the belayer switches back to lead line belaying for the bolt clip. Repeat process on each top lead bolt. If the drill needs to be ditched just tell the belayer to take in tag line and then lower it back down, with the belayer pulling it tight as it gets to the top bolt. Pretty simple stuff.
A few upside points: drill can't accidently come off the fifi and yard leader off. Drill ($$$) always has a dynamic belay as it goes up/down, static belay with no slack in system while it waits to be pulled. Drill below, or off of climber most of the time. Leader has control of how fast drill goes up/down without being pulled on (unlike pulley.)
Primary downside point: mess up the way the drill hangs from the draw (or accidently clip the drill in) and it's an "Oh, ^&%@" moment when you go to pull. It can get a bit tricky so one needs to pay attention to how it hangs, and how it will directionally pull - unless one doesn't mind jumping off or down climbing when it won't budge. Its also possible to have the drill go over/under the lead line inappropriately while pulling and cause a problem. These are the area where almost all fubar(s) occur with the system. If using a fifi already these issues shouldn't be anything new.
Like I said, it's not a perfect system or anything. Seems to work well enough though.
