I have an attachment for my cordless drill so I can attach my 6" Lazer auger to it. I believe the drill is an 18 volt. I get a good number of holes out of it but nothing like the Ion drills. I know that the batteries in the Ions are different in design as they appear to not lose power when cold like my drill batteries do. However, all batteries have a finite life. Is the battery in the Ion drills replaceable as they age and lose charge faster? How much do the batteries cost?