JoeLee
Joe,
Battery life depends on a lot of things. If you’re in a low signal area, batteries deplete faster. If you get more night pics, the flash depletes the batteries faster. I don’t recall whether you said what model you are running, but if it’s on older model that runs real time, that depletes batteries faster.
Is your solar setup for a feeder, by any chance, or is it with a largish panel (5 or 10 watt) on a decent-capacity battery (12 mAh) or larger? If it’s one designed for a feeder, that’s not going to be adequate for a camera unless it takes a couple of pics a day, and even then it’s questionable.
Is it possible that the external battery wasn’t plugged in securely or that it came loose or that the leads to the battery weren’t secure. There are all sorts of things that can go wrong with an external setup (personal experience there, lots of user error on my part at times).