I agree with Ed.. I am curious if the lifepo4 battery was giving 100w RF power in the past or never did? If not then you can parallel in more battery and save a little $. if it did give more power then there maybe some deterioration of the battery but "a bad cell" should show up as a drop in voltage of around 3.2volts..? your asking too much of that battery on transmit IMHO
73
KD9MDL?
Bill Lamm