Bad Battery???

If you have a voltmeter and battery charger you can do a fairly good test yourself. First charge the battery. Use the voltmeter to monitor the voltage, if it starts greater than 14.5V, and slowly goes down to 14V, then the battery may be showing signs of sulfation. If it starts out at 11V and slowly increases to anout 14V, it may just be discharged. When you think the battery is charged, often the charge indicator drops to about 2A, and stays steady. Charge time varies with the battery capacity, charge rate, and the charge in the battery when charging started. Typically discharging a battery to 11V is considered a deep discharge, and is not good.

The next step is to remove the charger and let the battery sit unloaded, if in the car, disconnect the ground cable. After an hour measure the battery voltage. The voltage should measure about 12.6 to 12.7V for a good battery. Next step is to connect the ground cable. Rig up the meter to measure the battery voltage while cranking, if it drops below 11V, the battery has a bad or weak cell. When the car is running the voltage should be about 13.8V, but may vary a few tenths.