Bringing the cooker up to temperature saves some battery life on the PartyQ, I bet the kamado style cooker makes the batteries last longer than on my UDS, but normally after a long pork butt or brisket cook, I change the batteries. It has a battery % left feature, but it can be misleading, because the battery draw is only a concern when the fan is running, so if you check it while the fan is not running, it will read high, but when the fan is running, it will be much lower. I bought two sets of rechargeable batteries for my PartyQ and I think that is a good way to go. I put a fresh set in each cook and don't worry about it anymore.
XL Big Green Egg, Weber Performer Platinum, WSM 22.5"