Timcredible

Having rebuilt my old black and decker 18v nicad lawn tools with 4200mah nimh cells a while ago, I'm used to much longer runtime that 1.5ah provides. So after buying a set of the 20v lawn tools (trimmer, edger, blower), I checked to see what would be a decent upgrade to the cells in here, and I found that Sanyo sells another battery with the exact same dimensions that are 3.0ah (probably what is in the dewalt 3.0ah pack - Li ion 18650 Battery Cell Sanyo UR18650ZTA 3000mAh). But, before I break out my soldering kit, I thought I'd ask if anyone has replaced these battery cells yet? If so, anything to watch out for? It looks like since there is already circuitry for making sure overcharging doesn't happen, that the upgrade would be very straightforward. Any info appreciated. Thanks.