Ryobi 18V Lithium Ion Battery

I purchased this battery to run the Ryobi fan. I have never used Ryobi tools before. I fully charged the battery, tested it, and everything seemed fine. Two days later when I went to use the fan, the battery was completely drained and would not even turn the fan on. I contacted the company, and was told that the battery should hold a charge for at least four weeks, even when plugged into the device. The seller asked me to try one more time, so I charged it up and then monitored battery status. It went down 25% every 2-3 days, and had lost all power this time within two weeks. We all decided that the battery had to be defective, and I was told to return it. I packaged it back up and took it to the post office, intending to send it Priority Mail as instructed by the seller. The post office asked me to sign a statement that said, among other things, that my package did not contain a Lithium battery. Since this is a lithium battery, I told them I couldn't sign the statement, and they explained that I couldn't send the battery Priority Mail (or any other way that involved flying); there were special instructions for how the battery had to be packaged, information that had to be included on the outside of the package (which Amazon supplied), and information about the battery itself that I pretty much ended up having to guess at as it was too technical for me. I was eventually able to send the battery back, but the entire experience was so negative that I ended up returning the fan and charger, and decided to go in a different direction. BTW, I was also unhappy with the company not being able to tell me how long any of their batteries might last running their fan. When I called customer service initially to try to figure out which battery to buy, they told me that one of their other batteries would last for 16 hours. When I mentioned that they should add that information to their web site, she said that's where she found it. When I rechecked, I realized she was reading information from a customer review, and that other reviews had quoted widely different times. You'd think the company would be able to tell you how long each of their batteries would last for each of their tools so that one could make an informed decision, but that was not the case. It doesn't really help to know that one battery will last twice as long as another when you have no idea whatsoever how long that is. The only reason I'm giving this 3 stars instead of 1 is that I know other people who use this fan (and battery) and have been happy with it. The company was also willing to take responsibility for the battery I got being defective. If I ever buy a lithium battery again, however, I'm going to do it locally so I don't have to worry about problems trying to ship it back.