If I ever suspect one of my packs is n/g, I throw it on the triron charger, peak it up, check to see how much it took initially and then discharge it on the charger at a rate of 20%, it gets warm, but after cooling, I recharge it and get a real # of what it can take, plus my charger can record all of this info for me to review, so if it took a long time to accept the charge and peaks out  well before the rated capacity and drains fairly fast for the rate, the chemistry inside the pack is deterioating to the point of just throw it out. Yhe old saying holds true, when in doubt, chuck it out.