Mary, By design, the battery in the standard Sonicare cannot be replaced. For the consumer and the planet, that's a pretty crummy design. To Sonicare's defense however, it probably is easier to design a reliably water tight product if providing internal access isn't something that has to be figured in.

Replacements -- Actually, if you'll Google some more, you find some eBay stores and no doubt additional websites that offer replacement batteries and/or the service of replacing yours. We have no first hand experience about these services other than they exist.

Good luck.