MagCable

This small piece can be used as a cable ending. It holds two 2x3mm neodym magnets (which I had laying around) to quickly connect a cable to a battery. You may have to scale it up or down by 1 or 2 percent for the magnets to fit as tight as possible. (no big deal as it usually prints in less than five minutes)
The top magnet might come loose while sticking to a battery sometimes. If it really bothers you, use some glue to fix it. I used a strong pliers to compress the solder drop at the end of the cable to a flat disc. Make it as thin as possible. That disc goes between the two magnets and holds the cable in place aswell. Have fun ...

https://www.amazon.de/dp/B07JHT1B9W?ref_=cm_sw_r_cp_ud_dp_D7E52DHQTKNH4KK5C9F8&pldnSite=1

The *.blend file is included in case you have different magnets at hand.