Unfortunately, there are a lot of fake
batteries around. There are a lot of disreputal manufacturers who are re-wrapping used lap top
batteries to make them look like a coveted brand name. Many of the batteries offered on Ebay and Amazon happen to be fake batteries, especially the more popular brand names (AW and Sony).
I'd stay far away from generic, no-name brand batteries. Also stay away from any brand name with "fire" in its name.
It's always recommended to purchase your mod batteries from the likes of RTD Vapor, Illumination Supply, Lighthound, Orbtronics, etc; who verifiy that they receive their supply directly from the main manufacturer.
The VTR has been known to be "picky" about the batteries that it will accept. Some of the 18650 batteries are a little too long to fit. I don't remember which batteries these are (you might find a thread on this if you do a search). I'm quite certain that the red
AW IMR batteries will fit the VTR, one of the most popular brands for years.
When choosing batteries for any mod, be sure that they are of IMR chemistry (and not ICR).
Battery Basics for Mods: IMR or protected ICR?
Deeper Understanding of Mod Batteries
For a battery charger, the most trusted name brands are Xtar, Pila, and Nitecore.