I've had my EE XXL for almost 3 months. It doesn't see a lot of use and has been working perfectly....Until tonight! All of a sudden, it wont work. It has an almost a full charge and the blue LED light comes on, but it totally doesn't work. I tried several different cartos and tried same on other types of PV's, so it isn't them. I also tried gently prying up the connection center post on the battery (as well as cartos) to no avail Can anybody offer and explanation or help?