Project: Cordless SDS Drill Battery Refresh Part 1

I love cordless drills!   I hate cordless drill batteries….   They never seemed to hold a good charge and always died at the wrong time.   But since buying myself a Milwaukee kit containing a combi drill with an 18V Lithium Ion pack that has become a distant memory.   Except for my cordless SDS drill.

Now combi drills are a nice idea.   A clutch so you don’t destroy screws with them and a hammer mode so you can poke holes in bricks.   The Milwaukee kit came with an 18V 1/4″ impact driver so I never use the combi drill for screws.   And I live in a house built in 1890-something from proper bricks and the hammer action on the combi drill makes a lot of noise and gently tickles the brick rather than making a hole.

I had to drill a big hole for a water pipe so I borrowed the cordless Dewalt SDS from work and WOW, I HAD TO HAVE ONE!!   A quick search showed a good few (it was 2009, they were not as common then) but blimey the prices!   Off to ebay, lets see what can be found second hand…. This!


A second hand and slightly battered (now more battered) Ryobi CRH-240RE.   The 2 joule impact knocks holes in bricks REALLY nicely!   The downside… it came with old Nickel Cadmium batteries…   It would drill a couple of 6mm holes and then die. *sigh*

I sourced some replacement packs from ebay which came with Nickel-metal Hydride cells instead of NiCad and they worked really well.   I used this drill to put a 4″ hole in concrete with a diamond core drill.   I was swapping the packs on and off the drill and charger with almost no rest time.

Skip forward 7 years and the packs are not holding charge any more…   Time for some investigation!


Each pack has 20 cells each.   I think they are ‘half C’.   Marked ‘Panasonic’ but I’m doubtful as they came from China.   Note that I put the NiMH cells in the old cases as the Chinese replacement packs would not latch properly!


Portly!   Nearly 1.5kg per pack!


Hmm… quite a bit of space in there… I wonder what will fit?