I have new Li-ion batteries for my mac but i wasn't completely sure on how to wire it up to the old circuitry. I know that "vg" is the ground and the "vp" is the positive. I am assuming "vl" goes to the wire "vl" i dont know what that is thought. But there is a "vh" spot on the new battery but on the old circuitry there was no wire going to there? Do I solder that wire there? There is also two very thin wires labeled ntc, i can not find a spot on the old circuitry for that is it necessary?