The 18650 is a conventional ICR Lithium Cobalt dioxide Round battery, available in various capacities including: 2300, 2600, 2900, 3100 and 3400 mAH.
Can buy directly from:
AW at
http://www.cpfmarketplace.com/mp/showthread.php?230876-AW-s-LiIon-Batteries-Sales-Thread-*Part-12*
Redilast at
http://www.cpfmarketplace.com/mp/sh...ttery-sales!-High-quality-Made-in-Japan-Korea!
[Can register using the same username, but must create a separate password to use CPF Marketplace].
Eagletac and several others also make very good batteries.
Callieskustoms too.
All are based on the Japanese Panasonic cell, with a Japanese IC safety circuit attached inside the tubing to prevent overcharging and overdischarging.
Other commonly used rechargeable battery types include:
1) the IMR Lithium Manganese oxide Round battery: these have a very fast discharge rate for a high amperage [not needed in H600], but that fast discharge rate/hi amperage comes at the expense of a much reduced mAH capacity for a much shorter run time.
2) there is also the rare IFR Lithium Ferrous phosphate Round battery: this chemistry gives a reduced voltage of 3.0 volts, to mimick primary disposable CR123 batteries which are also 3 volts, because some light are only designed to handle the disposable 3 volts, and these batteries require a special 3 volt recharger.
Because Power = Voltage multiplied by Amperage, these regular lithium rechargeables at 3.7 volts, or even the disposable 3 volts from the CR123 will generally give the light more power than NiMH chemistry which only delivers a puny 1.2 volts.
Also note that when batteries are added in "series", the voltage adds up, but he mAH capacity stays the same.
When the batteries are aligned in parallel, the voltage stays the same, but the mAH adds up.
A decent and very cheap charger at $15 is the Ultrafire WF-138/139; it will charge the most popular 16340, 18350 and 18650's.
A Jetbeam/Nitecore i2 2-channel or i4 4-channel Intellicharger at less than $24, and capable of charging up to 4 batteries, including AA/AAA Ni-MH and NiCad is also very good; a good compromise!
If you want outright quality, get a Pila 2-channel charger for around $50; can be hard to find...