Plugs

The original chargers used the Lester 21486 connector. This connector has three pins, and is really smart:

• Positive
• Negative
• Charge enable - AND IT IS SHORTER!!!

That way it will only charge if the connector is properly in.

It plugs in under the seat:

It is available for purchase on this eBay shop (non-original):

https://www.ebay.com/usr/rcfuther/

Also the female socket is available.

Part nr. to look for is 101828901.