I plan on buying a tk61 and was reading some of the articles about rechargabe batteries exploding and things like that. I figured since I'm going to be spending $160 on a flashlight might as well get the best batteries. So what would a great setup be for a beginner. I need 4-18650 batteries and a charger.
You need to research what the amount of room is, lengthwise and widthwise, for cells in the TK61.
Not all 18650s are the same exact size, so some tend to fit battery cradles and some don't. Protection, which is needed in a 4 cell light, adds to a cell's length and there is no standard.
We have cells approaching 70mm when protection is added and some are 18.70mm wide.
Smaller cells are the Eagle Tac 3400s, but because they're a big 'light company' they bend you over a fence, for pricing. Keeppower, Orbtronics, International, AW, Redilast, CalliesKustom, are all staggered in pricing, so look around for the better deals.
Most all of the big rebranders adding protection, are using top notch Panasonic, Samsung, LG and Sanyo cells, so if you're not sure, ask here before you buy.
There are 4 bay multi-chemistry chargers out there, that do Eneloop type NiMH batteries and lithium-ion ICR/IMR cells, but are a tad slower. If you want to kill two birds with one stone, do a search of the NiteCore i4 v.2, Xtar 4 Panzer, Thrunite MCC-4 and the Fenix ARE C2 chargers.
For dedicated lithium-ion charging, but having mostly two bays, I went with the Xtar line, which gets good reviews up until their latest VP2 that I bought and which was recalled last month due to a brittle plastic formula.
It's a nice charger while I used it and is quite flexible, but still only two independent slots, so buy two!
Chris