The Lithium-ion Battery is here to stay. The 18650 the most popular style
Lithium-ion batteries are constructed from two positive and negative electrodes separated by a liquid chemical electrolyte, such as ethylene carbonate or diethyl carbonate. The chemical composition of this battery limits it to a mostly rectangular shape. Lithium-ion battery capacity decreases over charge cycles and even discharges when not in use, which isn’t ideal. The 18650 size is by far the most popular for cylindrical cells.
PROTECTED VS UNPROTECTED 18650 BATTERIES?
18650 protected batteries have an electronic circuit. The circuit is embedded in the cell packaging (battery casing) that protects the cell from “over charge”, heat or “over discharge”, over current and short circuit. A 18650 protected battery is safer than an 18650 unprotected battery (less likely to overheat, burst or start on fire).
Unprotected 18650 batteries are cheaper, but we do not recommend their use. Unprotected batteries should only be used where the load/draw and charging is externally monitored and controlled. The protected batteries normally have a “button top”, but check the specs to make sure
Batteries are assembled to achieve solutions for many projects even including electric cars. Being a electric bike enthusiast doing my research proved that the best approach for these are 18650. WHY not the LiPo battery for an electric bike? A quality 18650-cell pack will last for several years of daily use, and any cost benefit you thought LiPo had…it just doesn’t pan out. LiPo is for high performance enthusiasts, but…the charging systems are too cluttered and complex, and although many LiPo users can assemble a pack together cheaper than a pack made from 18650 cells, a LiPo pack that is used daily to a full discharge/charge cycle will likely only last for one year of riding season.
HOW FREQUENTLY SHOULD I RECHARGE MY 18650?
The way you recharge your battery impacts the life of the battery. If you can measure it, you want to deplete from 3.7v down it to about 3v before you recharge. If you are not sure, use the device until it indicates a battery needs to be replaced. For a flashlight, run it till the light is dim or goes out.
A good charger will tell you the voltage of the battery so you can eventually get a sense of the life of the battery in various devices. If you recharge too frequently you “use up” the life without a return.
Li-ion batteries require a battery management system to prevent operation outside each cell’s safe operating area (max-charge, min-charge, safe temperature range) and to balance cells to eliminate state of charge mismatches. This significantly improves battery efficiency and increases capacity. As the number of cells and load currents increase, the potential for mismatch increases