For bikes, I just connector pins and sockets, and don't bother with connector housings/shells.
It tends to look like this after some heatshrink tubing is put over the pin and socket...
These connector pins and sockets are from Amphenol, and the part number is shown in the photo. I know they can be purchased from Digi-key (digikey.com).
These are used in construction equipment and are pretty reliable. The nickel plating makes them resistant to corrosion and fairly tough.
If you want to use a proper connector housing, Amphenol makes a somewhat smaller series of connectors called ATM that will save a little space...
http://www.amphenol-sine.com/pdf/cat...SERIES-ATM.pdf
These are also available from Digi-key. For instance, this is the kit for the two pin plug...
https://www.digikey.com/product-deta...216-ND/4415000
Steve in Peoria