18500 1800mAh 3.7V Rechargeable Protected Li-ion Battery 2 Pcs

The voltage of the Li-ion battery is 3.7V

• It is a super 1800mAh rechargeable li-ion battery, brand new and high quality

• Rechargeable Li-ion battery has high security, pollution-free, no memory effects, which is convenient to use

• With such rechargeable li-ion battery, you always have fresh batteries for your electronics

Size in Detail:

What rechargeable battery is:

• A rechargeable battery or storage battery is a group of one or more electrochemical cells. They are known as secondary cells because their electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging anything from a button cell to megawatt systems connected to stabilize an electrical distribution network. Several different combinations of chemicals are commonly used, including: lead-acid, nickel cadmium (NiCd), nickel metal hydride (NiMH), lithium ion (Li-ion), and lithium ion polymer (Li-ion polymer)
• Rechargeable batteries have lower total cost of use and environmental impact than disposable batteries. Some rechargeable battery types are available in the same sizes as disposable types. Rechargeable batteries have higher initial cost, but can be recharged very cheaply and used many times.

Usage and applications:

• Rechargeable batteries are used for automobile starters, portable consumer devices, light vehicles (such as motorized wheelchairs, golf carts, electric bicycles, and electric forklifts), tools, and uninterruptible power supplies. Emerging applications in hybrid electric vehicles and electric vehicles are driving the technology to reduce cost and weight and increase lifetime.[1]
• Normally, new rechargeable batteries have to be charged before use; newer low self-discharge batteries hold their charge for many months, and are supplied charged to about 70% of their rated capacity.
• Grid energy storage applications use rechargeable batteries for load leveling, where they store electric energy for use during peak load periods, and for renewable energy uses, such as storing power generated from photovoltaic arrays during the day to be used at night. By charging batteries during periods of low demand and returning energy to the grid during periods of high electrical demand, load-leveling helps eliminate the need for expensive peaking power plants and helps amortize the cost of generators over more hours of operation.
• The US National Electrical Manufacturers Association has estimated that U.S. demand for rechargeable batteries is growing twice as fast as demand for nonrechargeables

Charging and discharging:

Diagram of the charging of a secondary cell battery

• During charging, the positive active material is oxidized, producing electrons, and the negative material is reduced, consuming electrons. These electrons constitute the current flow in the external circuit. The electrolyte may serve as a simple buffer for ion flow between the electrodes, as in lithium-ion and nickel-cadmium cells, or it may be an active participant in the electrochemical reaction, as in lead-acid cells.
• The energy used to charge rechargeable batteries usually comes from a battery charger using AC mains electricity. Chargers take from a few minutes (rapid chargers) to several hours to charge a battery. Most batteries are capable of being charged far faster than simple battery chargers are capable of; there are chargers that can charge consumer sizes of NiMH batteries in 15 minutes. Fast charges must have multiple ways of detecting full charge (voltage, temperature, etc.) to stop charging before onset of harmful overcharging.
• Rechargeable multi-cell batteries are susceptible to cell damage due to reverse charging if they are fully discharged. Fully integrated battery chargers that optimize the charging current are available.
• Attempting to recharge non-rechargeable batteries with unsuitable equipment may cause battery explosion.
• Flow batteries, used for specialised applications, are recharged by replacing the electrolyte liquid.
• Battery manufacturers' technical notes often refer to VPC; this is volts per cell, and refers to the individual secondary cells that make up the battery. For example, to charge a 12 V battery (containing 6 cells of 2 V each) at 2.3 VPC requires a voltage of 13.8 V across the battery's terminals.
• Non-rechargeable alkaline and zinc-carbon cells output 1.5V when new, but this voltage gradually drops with use. Most NiMH AA and AAA batteries rate their cells at 1.2 V, and can usually be used in equipment designed to use alkaline batteries up to an end-point of 0.9 to 1.2V.

Reverse charging:

• Subjecting a discharged cell to a current in the direction which tends to discharge it further, rather than charge it, is called reverse charging; this damages cells. Reverse charging can occur under a number of circumstances, the two most common being:
• When a battery or cell is connected to a charging circuit the wrong way round.
• When a battery made of several cells connected in series is deeply discharged.
• When one cell completely discharges ahead of the rest, the live cells will apply a reverse current to the discharged cell ("cell reversal"). This can happen even to a "weak" cell that is not fully discharged. If the battery drain current is high enough, the weak cell's internal resistance can experience a reverse voltage that is greater than the cell's remaining internal forward voltage. This results in the reversal of the weak cell's polarity while the current is flowing through the cells[3][4]. This can significantly shortens the life of the affected cell and therefore of the battery. The higher the discharge rate of the battery needs to be, the better matched the cells should be, both in kind of cell and state of charge. In some extreme cases, the reversed cell can begin to emit smoke or catch fire.
• In critical applications using Ni-Cad batteries, such as in aircraft, each cell is individually discharged by connecting a load clip across the terminals of each cell, thereby avoiding cell reversal, then charging the cells in series

Common rechargeable battery types:

• Graph of mass and volume energy densities of several secondary cells

Nickel-cadmium battery (NiCd):

• Created by Waldemar Jungner of Sweden in 1899, based on Thomas Edison's first alkaline battery[citation needed]. Using nickel oxide hydroxide and metallic cadmium as electrodes. Cadmium is a toxic element, and was banned for most uses by the European Union in 2004. Nickel-cadmium batteries have been almost completely superseded by nickel-metal hydride (NiMH) batteries.

Nickel-metal hydride battery (NiMH):

• First commercial types were available in 1989.[20] These are now a common consumer and industrial type. The battery has a hydrogen-absorbing alloy for the negative electrode instead of cadmium.

Lithium-ion battery:

• The technology behind lithium-ion battery has not yet fully reached maturity. However, the batteries are the type of choice in many consumer electronics and have one of the best energy-to-mass ratios and a very slow loss of charge when not in use.

Lithium-ion polymer battery:

• These batteries are light in weight and can be made in any shape desired.

Battery Capacity:

• Look for batteries with a higher milliampere hour (mAh) rating. This refers to the amount of electricity delivered at any given moment. Electronic devices can handle a range of mAh without damaging the device. So as the rechargeable batteries begin to lose power, they do no damage to the device. Batteries with a higher mAh may look exactly like a battery with a lower mAh but typically they cost more.

Battery Chargers:

• Buy the battery charger that suits your needs. In some instances you can purchase the charger and batteries as a package deal, but if you want your battery charger to maintain your rechargeable batteries properly, you may need to pay more for special features.
• Look for a battery charger that recharges a variety of battery sizes. Select a unit that has a reconditioning cycle. This keeps you from overcharging your batteries. Some models do this automatically while others have a switch you must flip to go into reconditioning mode.

Warnings:

• Do use the specialized accesory to recharge
• The input voltage of any appliance must be in the range of the output of the battery, otherwise it can do harm to the applince
• To avoid the decending capacity, the battery must not be put away over 1 year
• Away from high temperature, and kept in cool dry place

Package Included:

• 2 x Rechargeable Li-ion Battery