Best 18350 ptotected batteries for shorty Convoy S2+ and Astrolux S1

LED Flashlights – General Info 18650 Flashlights
3

since those lights have low voltage protection, you might go with

Test/Review of Windyfire IMR18350 850mAh (Red)

Mtnelectronics has them (and provides a link to the review by HKJ)

Else try protected 18350 - Google Search (and set the search tool to “verbatim”)