As @Tam mentioned... those should not be used together in the same mod because they are two different batteries (amp limits, and capacity). One looks like a Samsung 30Q, and the other could be a Samsung 25R, but could also be a Sony VT series (4, 5, or 6)? Using them together will cause one to eventually fail, catastrophically. As for the fraying wraps, they can be re-wrapped, but I would honestly recycle them and pick up two NEW pairs of matching batteries. Label them A1, A2, B1, B2, and use them in matched pairs, rotating their position in the mod each time you change batteries. They will last longer and be more reliable that way.