I use rechargeable energiser lithium AAs as even the strongest alkaline batteries by the top brands last maybe one hour at best with my Casio PX S3000. The lithium last at least 4-8 hours, I’ve noticed it makes a difference how long the keyboard is on for, if I play half an hour once a day they’ll last for weeks but if I play for two hours straight it’ll be starting to give the low battery warning light and will die within ten minutes after that. But if you teak a half hour break then play again it’ll probably be good for an hour, so it’s risky for long gigs but handy for outside choir rehearsals etc of course you can always have a spare set of batteries to swap over. I wish they’d put rechargeable lithium built in like some cheap foldable pianos are doing now, that would be so handy
