These are the "BulkHead" Connectors I have in use.
Links (Amazon.com) & Notes provided.
Fastronix Premium High Current 3/8" Thru Panel Battery Terminal Connectors
Link for the pair
These are large (1-1/4" - 35mm) width & Bolt is (2-1/16" - 55mm) long
You can twist the copper through the "grommet".
13 mOhm resistance through the terminal.
These re somewhat awkward and depending on the "box" being used may not be suitable.
Blue Sea Systems Terminal Feed Through Connectors 3/8
the Plastic barrel is 7/8" - 25mm wide, Bolt is (3-1/8" - 80mm) long
Red Connector Link
Black Connector Link
14 mOhm resistance through the terminal
These are much easier to use and the wide face has 2 screw holes for attachment. Contact Surface for the terminals is excellent.
3/8" Copper Battery Terminal Stud Connector, Ampper Remote Battery Binding Post Junction Post Block Terminal Kit, Pack of 2 (Red and Black)
Link to set
Similar are installed in my Samlex Inverter/Charger (supplemental input NOT the primary DC Cable input). I cannot provide measurement or Resistance values. ! Best Bang per Dollar.
They are very solid and secure, excellent for a thinner casing material (metal, ABS etc) These are ideal for Battery Boxes, see the link for more details AND look at the price, an excellent value !
Hope it helps, Good Luck.
Steve_S