I don't really understand what you're doing here since your description is sketchy, but generally speaking you simply can not safely charge a Li-Ion battery without a charger controller. The thing is voltage has to be regulated to 4.2V exactly and current has to be limited to the maximal charging rate, usually no more than 1C or one times the charge of the cell. To try and attempt this without using some kind of device that regulates voltage and current exactly is asking for trouble. If you are charging without a controller it's your prerogative to attempt this despite any advice on my part, but for anyone else don't do it.
Furthermore, the eGo type batteries don't use a direct connection to the Li-Ion cell. They use a scheme to handle the double duty performed by the atomizer connector. As such, they require a special type of Li-Ion charger that is compatible with the e-cig's electronics. So a normal Li-Ion charger will not work properly with one of these e-cigs. Specifically, the e-cig's electronics poll the connector for charging voltage which confuses a standard Li-Ion charger. The e-cig itself does not regulate charging voltage or current, it only performs the function of switching the connection between charging and vaping.
The more advanced eGo type battery units (like the variable ones) have additional safeties to protect the cell from various faults including over-voltage due to a charger fault. In that case it will disconnect the cell once charger voltage exceeds an amount over 4.2V. This is purely a safety feature to protect the cell in the event of a charger failure and is not something to be relied upon for normal charging. Also you you can't assume all e-cigs provide these safeties. The standard eGos have none of them. If you put 5V on a standard eGo 5V will be applied to the cell, then boom.