Unfortunately, the volt meter by itself will only give you the surface voltage of the battery. It will not place a load upon it which may indicate a problem if the reading drops substantially after a full charge. I've had batteries that tested over 5 volts after a full charge, but under load they dropped faster than you could keep up with. Down to below 4.7 within a minute or two. One of them caused me a bunch of ignition woe until I found the problem and replaced the battery.