The output should be listed on the charger. It generally takes about 15 hours to charge a dead pack. Buy an extended volt meter. The meter comes with great tips on maintaining and monitoring the condition of your batteries. NiCads are great batteries. But you need to understand how they discharge. And you need to know how your particular packs discharge. You can plot the graphs using the expanded voltmeter and take much better care of your batteries and therefore your investment.