I try to boot a Zero W with LiPo Modul https://shop.pimoroni.de/products/zero-lipo
When I connect a Battery or a Power Supply to LiPo Modul Zero start to boot but at one point (I guess when starting WLAN) it reboot. This behavior loops endless.
When powering Zero W with USB Power (Powerbank or Power Supply) it is booting fine.
Most likely the undervoltage lockout on the Zero Lipo triggers as the input voltage drops during larger current spikes. Try using shorter / thicker battery wiring or a bigger battery, that might fix it.
I’m using 0,5mm wiring which is enough for 12A. I’m using 4,7V from a constant powersupply so I can deliver more than 50W of Power. My Powersupply is designed for 100W.
As you see in my video voltage is never below than 4,7V.