Be extremely careful with that trustfire charger , it's probably not an intelligent charger and can overcharge your batteries leading to a very bad situation as in batteries go boom and set fire to your residence , I would replace it with a nitecore or pila intelligent charger as soon as possible and monitor your batteries carefully for voltage with a multimeter when charging .
I am new to vapeing, but have a strong fixation with high powered flashlights. Over 3400 mAh is generally more power than I would want to mess around with in a handheld device. Is your cell a "high drain"? That is the type of cell that strong Mod's need to satisfy the current demands. AW IMR cells are a good safe bet. I use his protected cells for most of my lights and trust their quality. When it comes to mAh I value quality over quantity. I avoid anything with fire in it's name. For what it's worth the best charger I know of for Li-Ion's is the Pila IBC. Mine has worked flawlessly for the past four years.
If not why not get a nice flashlight to use it in? Never know when a good quality light may be needed. Off the top of my head this one for about $65 comes to mind;
