Which terminal is positive and negative on a plug like this?
Came off of a older battery tender wire.

 

If this is the pigtail connected to the battery, the exposed metal prong should be negative. If you flip it over it may be labeled.

 

Depending on what's on the other end battery or tender?

 

If it is connected to a battery, the exposed terminal is negative.

If it is connected to a battery tender, it is the positive side.

You cannot use this pigtail to jumpstart the bike, in case you were wondering.

 

On mine once cable is grooved, the other plan. The grooved one is "+" on the HD Charger.

 

FWIW, the wiring going to the plug/terminal has one wire is smooth ( that’s usually +) and the other has ribs along the side( that’s usually -). Just my observation. 110v 2/ wire extension cords have the same ,one smooth (+) and one ribbed (-) wire.

 

Sounds like you know this from personal experience?

 

Sorry, no funny story here.

I know it because I understand how the bikes and these components are wired.

 

First pic is something that looks like it might have gone to heated gear or something else with that plug configuration. Second pic is a generic trickle charger plug. That one fits my Deltran battery tenders, TecMate Optimate, my black and decker battery tender (yup they made em and it still works), and the overpriced HD ones which I think are just Deltrans with a HD logo on them.

 

There is only one picture, I think you got on this thread by mistake...