Quoted:
Where would the best deal be found on this?
I need probably up to 10 batteries and 1 charger.
Thanks to all the flashlight junkies who chime in.
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First off, I'll once again sound like a broken record, but so be it.
Never go cheap with Lithium-Ion cells and chargers and make sure you HAVE a decent digital multi-meter handy before you start playing with them.
If you have to go cheap on something, buy cheap NiMH batteries, cheap beer or cheap toilet paper, not Li-Ions.
TelephoneMan uses the same guy I've used for 19 months and he's now a very experienced seller, thanks to the the boom in E-cigarettes, which make Li-Ion cells/chargers almost ubiquitous these days.
If you just need to charge up lithium-cobalt, or lithium-manganese 3.7v cells, which are common in high end lights, then Xtar is the de facto king of chargers these days. You can get easily get the dethroned king--the Italian Pila, but it's a bit slower in charging, is expensive at ~$50 and specifically built for Pila designed batteries, although that latter point is less of an issue in reality.
Xtar makes the WP2 II 2 bay charger, which is the one I have. $21 shipped if you don't 'make an offer' and get it for less. It's a safe charger that charges at 500mA and 1A, plus it has a USB out at 5v-500mA, so you can charge up most USB devices, with an already charged up cell, if you need to. Finally, it, like the other Xtar chargers, comes with a 12v cigarette adapter.
500mA and 1A are two rates that cover most Li-Ion sizes, but not all. 500mA is a little too hot for those using the AAA size 10440 (and smaller) cells and current 18650 cells can take a 2A charge, but suffice it to say, the 500mA and 1A rates are right in the sweet spot, IMO .
Xtar makes the newer XP2s, SP2 and VP1 chargers that have either higher, or lower rates (2A vs. 250mA,) which allow you to have a bit more flexibility if you use smaller cells, which I don't. The RCR123/16340 (CR123A size) is the smallest I use and 500mA is borderline, but sufficient.
You'd always rather charge a cell up to 'just under full capacity' than to go over, which can be dangerous and this is where cheaper chargers fail. There's is a certain 'cc/cv' algorithm that 'should be followed' for Li-Ions and problems can occur if you fail in this regard. The cheaply made shit couldn't care less about this algorithm.
Anyhow, see my guy here: R-Lsales and you can click on 'other items' to see his cell choices:
r-lsales on Ebay Xtar WP2 II and cells
If anything, you can start researching some of the things that I discuss here and see what you see for pricing.
If your lights are high drain/high current draws, you might want to consider the Sanyo 2600s, which he has, as they handle 3+ amp loads better than the protected Panasonic 2900s, 3100s and the 3400s, but since they're unprotected, you wouldn't want to use the naked Sanyos in a multi-cell light. Other people add protection to the cell, but the price goes up, FWIW.
Chris