You can also get yourself a smart charger. Most of the newer chargers will tell you how long the charge cycle lasted, and knowing the charge rate, you can determine how many milliamps you put into the battery. If you check the voltage at the start of the charge cycle and look at the amount of current put into the battery, you can get a rough estimate of the health of your battery.

If you're concerned, using an expanded scale volt meter or a dummy load on a standard volt meter is your best option, as long as you know where the cutoff voltage should be.

Brad