PSA: do add a strap around your downtube battery : r/ebikes
E-bike Battery hailong Base Mount Plate Bracket Holder Downtube electric Bicycle | eBay
Hailong 36V 48V Battery Base New version 5pin round Connector for Electric Bike | eBay
Electric Bike Battery Bottom Base GPS Tracker 5PIN Hailong Battery Holder E-Bike Bicycle Frame Downtube
DRIFT MANIAC Ebike Coversion Tool For HaiLong 24V/36V Bicycle Frame Battery Mount For Changing Handlebars On Bike Components 230907 From Heng06, $17.73 | DHgate.Com