I was most Disappointed with these Panasonic replacement batteries for my cordless phones. I followed the charging instructions, and let them charge completely before using the phones. The charge lasts just as long as the original batteries that I was replacing. NOT LONG at all. So it seems, the new batteries don't hold their charge well. Even in stand-by when not in use. I love Panasonic products, but these batteries are the very first time that I've been let down by the brand. I should have ordered the generic replacement batteries for $4.00 and saved myself some cash.