Updated almost 4 years ago on .
Tip for Users of DeWalt 18V XRP Tools ...
DeWalt's 18V XRP batteries are NiCads and, as such, exhibit all the usual NiCad issues such as "memory" and self-discharge. They're getting to be a bit hard to find as replacements, also.
3rd parties make an 18V NiMH battery which fits the tools nicely, but does NOT fit in the DeWalt charger for NiCads. If you order the NiMH batteroies, be sure to order the matching charger at the same time. It appears to also charge the NiCad batteries, but I have not yet confirmed this.
Newer DeWalt tools use a 20V Lithium Ion battery. DeWalt also has an adapter to allow the older 18V tools to use the newer batteries. The caveat with the adapter is that it fits quite snugly into the tool and can be difficult to extract. So, attempting to move one adapter from tool to tool may be inconvenient, at best. Fortunately, the adapter is cheaper than the NiCad batteries - about $30, +/-. So, order one for each tool you want to adapt to the newer 20V batteries.
DeWalt sells a 20V "Starter Kit" with two batteries and a charger. The kit does NOT, however, include an 18V adapter. The adapter(s) needs to be ordered separately, usually from the same supplier.
Hope this helps ...