Hi, I have a similar problem; bought a combo pack (H-Drill, C-Saw & J-saw) from B&Q a couple of years back. I have two batteries with the pack one which is not holding charge at all and the other has a very low lifespan (compared to how long they did last).
The chargers (PP Pro) can still be bought from a few B&Q stores, but none are stocking replacement batteries (these are the 18V with 4 prong connection in a shielded housing). It seems the design of battery pack has changed, and worse still these are being phased out for the new Li-Ion reachable packs.
My local B&Q in Wigan is selling of some old battery packs for a reduced price; these however have a different connection but are same voltage and type (N-Cad). If they still have some reduced ones this weekend Im going to get one to see if the physical bat pack (inside the case) can be modified to suit the required connection.
(Being technical: the bat cells are connected by metal strips which are spot-welded to the terminals – I know this because one of my bat packs stopped working and after opening the problem was found to be a broken metal strip – this was relatively easy to fix by soldering a new wire connection)
Dave T: it may be worth you opening the bat case to have a look – assuming that is you have a dodgy bat rather then actually need one!!
Jamie, October 2008
