The only way to know for sure that your batteries are still reliable is to run a controlled cycle. That means charging for 16 hours at 0.1C (you do not have to discharge first) then discharging at a controlled rate of not greater than .25C (preferably at .2C) down to 0.9 volts/cell. If the resulting value is at least 80% of the rated battery capacity, you are relatively safe to continue using them. If the batteries have been dormant for an extended period of time, you may have to repeat this slow charge/discharge procedure two or three times to bring the batteries up to full capacity. Check out www.rcbatteryclinic.com or www.batteryuniversity.com/parttwo-33htm and/or http://members.aol.com/davthacker/balancecharging.htm for some good reliable info on the care of your batteries.