ORIGINAL: Kaos Rulz

Your battery is looking good if your getting an initial voltage reading of over 6v for a 4.8v battery. It is not uncommon to lose a few tenths of a volt initially, and after a couple of flights the volatge should read at, or above, the battery's rating. In this case 4.8v. In fact you should be able to fly after the voltage dropps to 4.6v. With a good battery, properly charged, you will notice its voltage will stay at the 4.8v for a good while before dropping below 4.8v.
Now the main thing I noticed with your post is you're not getting the best charge for your batttery by charging at the 125 ma rate. Even for an onernight charge you should be at least at a c-10 charge rate. In this case 240 ma. I usually charge at the c-10 rate plus 10%. That equates to about 265-275 ma, depending on how accurate your charger is. These batteries can take a higher charge rate, but I like to baby my batteries and charge slow in hopes of battery longivety.