Battery life is an interesting one. Motorola has reduced the battery from 3,510 mAh to 3,000 mAh in the Moto Z2 Play, while opting for largely the same SoC and display. While I don't have any battery data to form a direct comparison, compared to the Moto Z Play there's no doubt the Z2 Play will produce downgraded battery life.
From the above battery results, the Moto Z2 Play isn't particularly amazing. It performs well in mostly SoC-limited workloads like PCMark and Basemark Web, because the S626 is slower and consumers less power than the S835 in flagships like the OnePlus 5 and Xiaomi Mi 6.
However when moving to web browsing tests, and any situation where the modem has to be utilized, the Moto Z2 Play falls back into the middle of the pack. The Xiaomi Mi 6 and OnePlus 5 either outperform or match the Z2 Play, which is disappointing as mid-range phones typically pack better battery life relative to their battery capacity.
I'm left a bit puzzled here. If Motorola had utilized the same battery size as the Z Play - in other words, if the battery was 17 percent larger, the battery life would be a real winner, outperforming most flagships on the market. But because Motorola went and shrunk the battery capacity for the sake of making the phone slimmer, battery life has suffered and it's not the standout option it could have been.