Definitely test with a multimeter but it's likely that the two red wires are just to carry extra current - ie they're both positive.
It's actually possible they go to different cells - in this way you can get more current (less internal resistance) by paralleling them up or greater voltage by putting them in series; or even split supplies (+ and -).
You can determine this (as Matt says) with a meter but test for continuity between the red pair and the black pair (but not a red and a black because that might make magic smoke come out of your meter).
Take everything I say with a pinch of salt, I might be wrong!
@marcdraco yes I've tested and both red wires are positive and both black being negative. Thank you all!
Luckily there's no smoke yet...
That is the standard colour code - even the Chinese use that thankfully! 🙂
What I meant was are the two banks of cells isolated so you can get 7.4V at low current or 3.7 at a much higher current or + and - 3.7V.
Doesn't matter, I'm just curios as I've not seen on like that before.
No magic smoke is good. I did that to my ex wife's Karcher window vac while replacing the LiPo and hit the wrong pair (damn careless of me, no excuse) and I think the Genie hid behind the smokescreen while the neighbour called the fire brigade.
Still works though.
Take everything I say with a pinch of salt, I might be wrong!