It looks like brute force wins over high-tech. The three-cell ESP is still going strong, with a lot of headroom left from the batteries. My two-cell ESP with fancy boost converter used up its 2nd set of batteries already. I blame the standby current of leaving the boost converter powered up 24×7 while the esp sleeps (my theory at least.)
![](https://sp-ao.shortpixel.ai/client/to_webp,q_lossless,ret_img,w_530,h_352/https://everythingesp.com/wp-content/uploads/2019/03/esp12_bats.png)