Cigar lighter polarity question

[eucharistos]

I am trying to make a cigar lighter attachment for my battery tender (’02 RT/10). Can someone tell me if the center of the socket is positive and the side collar negative? Thanks in advance for the help

p.s. have really enjoyed reading the various posts – educational and entertaining

 

[1932highboy]

center is postive.

 

[Vic]

that's right!

 

[eucharistos]

Thanks for the help, didn't want a "what's that burning smell?" moment