Charger barrel - making sure the polarity is correct?

[netrate]

Two questions surrounding the charger and the polarity.

1) Ok, I ordered a new charger for my Gio escooter/ebike - it is arriving today (at some point). The polarity of the new charger seems to be the exact polarity of the old charger (see first 2 pics - first pic is the new charger, the second pic is the old charger).

2) The wires connecting to the barrel end of the charger came loose and I am not sure which end/lead the red wire goes to and which the black goes to the barrel (I do have pics that I took, but I am paranoid and want to be doubly sure). I don't want to short out the batteries when I get the new charger - so is there a way to tell which is which? (Pics attached of the piece and my reconnecting of the wire temporarily)

 

[netrate]

I figured it out. The charger I bought with the bike was the culprit. I lined up the red with positive and the black with negative on the barrel socket connector and used the new charger - worked perfect!