kindle d graphite sudden battery discharge - help

[man1337]

Hello everyone, since I jailbraked my kindle and installed kindlepdfviewer my kindle started with this problem. The battery drain is normal, up until 60% then randomly when I start it in the morning the battery is drained, sometimes it happens even when I'm reading. I don't use it really that much, it gets a full charge usually once a month (when this happens). And I always shut it down completely even when I stop for just 1 hour or so. When I use kindlepdfviewer it frequently crashes. Hope you can help