Sent a photo with K9 at night. Not sure if it was the culprit but it did send the photo, apparently. Woke up this am to find the full charge was gone and phone dead. Plugging it in resulted in the phone rebooting a dozen times. Fortunately a long battery pull got the phone to start up.
I only have weatherbug in there (which many are using successfully) mylock beta (which works most of the time) and ring guard. I do notice that some apps grab services even when totally unusued. e.g. cragscherkerservice, financewidgetupdateservice, screebl (turned off), quoteupdater, gtalkservice.
I wonder whether any of these unused background apps are causing crashes and I find it alarming so many operate almost secretly... need to find the cause to this so it doesn't happen again.