Unprotected Li_ion Cells
Unprotected Li-Ion cells should only be used by people who are versed in all aspects of handling them as improper use can render them dangerous. If stored, charged and handled properly, and used in single cell lights or power packs that have protection circuits built into them, these cells can be used safely. If you are new to using Li-Ion cells you should spend time researching the subject. A good starting point would be reading these precautions from one of the manufacturers.
However, the reason this battery chemistry is popular is because you get higher voltages and the most capacity for the amount of weight with Li-Ion, almost double that of NiMh. If you are going to use one of the Power Packs to charge your 18650 cells and also to charge your USB equipment such as phone, GPS, etc., then you will need to use the unprotected cells, therefore all the Power Pack/Chargers we sell have protection circuits. It is considered safe to use these cells in the Spark headlamps because the headlamps all have protection circuits built into them. In spite of this, many users also prefer the added redundancy of the safety margin afforded by using protected cells. We use unprotected cells daily, and follow the safety procedures to avoid mishaps.
Panasonic NCR18650BD 3.7V 3200mAh Rechargeable Li-Ion Batteries: $12.95 USD (each)
You may be aware of these batteries already, because Dyson uses them in their cordless vacumns. The reason these are special is their ability to sustain continuous current discharge of 10amps. Weight 48g. Capacity 3100mAh
Panasonic NCR18650B Rechargeable 3400mAh 3.7V: $8.95 USD (each)
These are the Ferrari of cells, about the best money can buy. They have the highest mAh capacity currently available. These are what we run in our eNB power pack and carry on multi day backcountry trips. Weight: 46g.
GP Unprotected 18650 Cells: $2.95 USD
These are 2200mah cells and weigh 42g. Thier best use is for EDC (every day carry) when you are going to be recharging almost every day, such as an evening run or walking the dog, working around the house, etc.
Data Sheet: (Click to open in new window)
Samsung ICR18650 4.35v 2800mAh $7.95 USD
This 46g cell is the sought-after cell that Flashaholics use to squeeze maximum brightness in terms of boosted lumen output from their lights when they charge it in a charger that can charge to 4.35v instead of 4.2v. However, even if you don't have a special charger and charge it in your regular charger, it will have an extended lifetime several times over because you are limiting your charge depths just like vehicle manufacturers do to extend battery life. The best use of this is if you want a cell that is going to last you for years, or if you have the correct charger: a cell that will give you brightest possible output your light's circuit will allow.
Sanyo UR14500P 14500 840mAh Li-ion Battery (unprotected) $5.95 USD
Use in devices that take AA format. Note this cell is 4.2V, when used in Wouxun battery pack or Spark SD53 requires the use of 'dummy' spacer cells.
UltraFire 10440 3.6V 600mAh $6.95 USD (pair)
These are AAA format Li-Ion rechargeable cells. Good for use in Wouxun KG-816 radio, and Spark SD73 headlamps.