Let's review your charging situation.
What are you plugging the chargers into?
If you are using an AC to USB adapter it has to provide a minimum output current of 500 mA. (Or 0.5 A - same thing.) More current is fine - it just means the AC adapter is capable of providing more current than the eGo charger will ever draw from it. BUT under powering an eGo charger with a low capacity AC to USB adapter does cause problems and the charger cannot work properly. There are some low power adapters out there for older cell phones and all sorts of cheap electronics that only provide 300 mA current, some even less than that.
The other thing you want to look at is if the adapter says "Input AC 120 volts" or not. A while ago there was a run of knockoff eGo batteries being delivered to US vendors with AC adapters designed to work at 220 volts. And a subsequent run of charging complaints reported on ECF. There is no surprise here - if you got one of the 220 volt AC adapters it will say so on the ratings plate.
So please check that bitty writing on that tiny plate on your AC to USB adapter as seen what you got.
On the eGo charger dongle itself that ratings plate should read:
Input: DC 5 volts, 500 mA
Output: DC 4.2 volts, 420 mA
Always keep your 510 connector on your batteries and charger connection clean and dry. (Q-tip works fine.) E-liquids are actually non conductive and liquid in the connection to the charger is also known to interfere with charging.
As an aside it will also interfere with your vape experience. Having a 'meh' eGo experience? Remove your device, swab any liquid out of the 510 connector on the battery and the clearo and see what a difference that makes.