depends if need to disconnect
if no disconnect use quality splice
if yes look here
https://www.ebikes.ca/shop/electric-bicycle-parts/connectors.html
can use automotive bullets to match current connector
although many would not recommend
i would use anderson power pole
too bad this thread directs to bad powerwerx link
https://endless-sphere.com/forums/viewtopic.php?f=2&t=17969
read stickies and search "connectors + wire"