My home security system, a DSC PC500, was on the fritz. Battery kept dying every few months. These are specialty batteries that aren’t cheap ($30-40). And a service call to the security company would’ve broken the bank. So I ordered a Battery Tender Jr. from Amazon.com. Now, every few months, I charge up the battery overnight and I’m good to go by morning. Yeah, it’s another thing to do, but it beats shelling out to the security company.