Prolong Battery Charger Plug

Have you looked on Amazon... I had one of the units and it seemed like a plug you could purchase online.... then splice using a continuity tester.

 

does it have pins and how many or is it female?
Picture of plug end?

Google din plugs

 

If you're just replacing the connectors on the ends, you just get a pair that match each other and have the right number of terminals (four, iirc). Then replace the old connectors with the new ones making absolutely sure you connect the two cables exactly like before. Other than the number of wires, they don't need to match the old connectors, just each other. Hence the need for the tester that @Tim Jones mentioned.

 

Something like this might work if it fits the case. You'll need to replace both parts. I'm not home, so I can't look at mine (which is VERY old). All you really need is a 4-pin connector that fits.
Perhaps this?

And, from now on, don't connect or disconnect that connector when the charger is plugged in. I did that one time, saw the spark, and said, "Not doing that anymore!" Breaking a DC connection under load makes a lot of arc which burns up the contacts. I got the same kind of arc screwing in and unscrewing the lightbulbs in the manual discharger. But light sockets and bulbs are easier to replace.

 

Must be your ad blocker. It's there. Every once in a while someone can't see the links. I don't think it's ever been anything but an ad blocker.

Sounds perfect. I wonder how it got so scorched looking.

 

I assumed you would replace both ends. I certainly would.