I had the same basic experience with my AT Max, which I used exclusively between March 2018 and November 2018. My previous detector had been an Ace 400, and while I expected there would be a difference, I was surprised to notice a significant decrease in run time when I switched to the Max. I had already made the switch to rechargeables when I bought the Max, and I was using Eneloop Pro AAs at the time. On my Ace, I was getting 10-15 hours with the Eneloops. I seriously didn't get much more than 5 or 6 hours out of the Eneloops on the Max. I quickly relegated those to "backup" duty, and bought an RNB Innovations power pack. Things improved enough to be manageable with the RNB - I was getting 10-12 hours of hunt time consistently, so I didn't feel like I necessarily had to recharge after every hunt. I never tried traditional alkaline or lithium AAs in the AT Max to compare, but there was no doubt in my mind that the Max was more of a power hog, in general. I always used the wireless headphones, so the internal z-lynk was always active - I'm sure that played a role in the reduced battery life.