The balance wire pulled out, so my friend gave it to me. I was wondering if I could still charge it and just not balance it.

You could. I would try to fix it. Open it up and solder accordingly.

I wouldn't worry about it honestly. I almost never ballence my lipos. Though I do check them from time to time and they are almost always withing a hundreth or two. I also run higher end lipos. I'd say if its free run it and have fun. When it puffs you know its out of ballance too far and done.

Opening it up you could cut into the pack and cause a fire so if you do it do it outside at least and be careful. Have a flower pot full of dirt ready and be prepared to burry the battery.. better yet dig a small hole and have some dirt handy to bury it with. fire extinguishers dont work well on lipo fires.

Yeah, I'm not a fan of opening it up. I just haven't charged a lipo without balancing them. I'm assuming you don't need to plug in the balance wire to just plain charge it. Which I like, cause I'm going to give it to my little brother to use with his slash 2wd so he can have fun.

Like you said, its a free battery. Just use it until its toast.

If it is only 1 wire that is pulled out all you need to do is measure the voltage on the power connection ( big plug) Then measure the voltage on the 2 good wires on the balance plug.

Subtract the voltage of the balance plug from the pack voltage.
That will give you the voltage of the cell that is disconnected from the balance plug.

Then you will know the individual voltage of the 2 cells.

I had this happen a week or so ago. I had a 2yr old Checkpoint 5000mah that broke internally after I nosed on a big double. I have opened them before to repair a connection but this time I punctured a cell and up it went. 30 plus foot smoke cloud for a good ten minutes. If your gonna attempt it definitely do it outdoors.

What did your niehbors do?!? LOL

Free is a good price to pay, & if battery does fail, cut the both ends off and save.
Never open a Lipo till you understand the dangers, get some one to assist with knowledge or read up before you attempt to open. I can tell you that the plastic film that separates the battery material is thin & if damaged allowing the two internal cells to short, It's Flower Pot Time, as this lithium material is volatile.
If your not so great a solder I would ask some one local who is to help. You will get more life from a battery balanced. Typically new you get 500 charges, that's running once a day for almost a year and a half. Charging, storage voltage, never venturing below 3.0v or 6v for a 2 cell, are all important factors to a Lipo's life span as well.