Battery Terms

Voltage - The number of volts providing the pressure behind the electric current.

Amp Hours - A measurement of battery capacity, obtained by multiplying the current (in amperes) by the

hours during which the battery is discharging.  The more amp hours, the longer the run time.

Mil Ampere Hour (mAh) - One 1/1000 of an Amp Hour.

Rated Capacity - Usually measured in either “Amps” or “Milliamps”, the rated capacity is determined by the

cell manufacturer.  This number is then used to determine run time and is also used for warranty purposes.

Capacity - The amount of energy available in a battery, usually expressed in Amp Hours or Milliamp Hours.

Cell - A container that holds all the chemicals and components necessary to produce an electric current.

Technically, a battery consists of two or more cells, although a single cell is sometimes referred to as a battery.

Shelf Life - The amount of time a battery can be stored before it discharges.

Self Discharge - The discharge that occurs in a battery while it is not in use.

Charge - To restore the capacity of a cell by means of an electric current.

Condition - To restore the capacity to a battery by cycling the battery three times.

Cycle Life - The total number of cycles a battery can undergo before it must be replaced.

Discharge - The conversion of the chemical energy stored in a battery to electrical energy.

Memory Effect - When a battery, especially a NiCad, loses some capacity from undergoing partial instead of

complete charges and discharges.

UPS - Uninterrupted Power Supply.

Ways to Connect Batteries

Series - The positive terminal of the 1st battery is connected to the negative terminal of the 2nd battery.

The voltage becomes the sum of the individual batteries. The capacity of the battery is unchanged.

Parallel - The positive terminal of the 1st battery is connected to the positive terminal of the 2nd battery.

The capacity is the sum of the individual batteries and the voltage is unchanged.

Primary Batteries

A battery that is not rechargeable.

• Voltage:  1.3V-1.5V per cell.

• Alkaline / Manganese - AA, AAA, C, D & 9V

• Mercuric Oxide (HgO) - Medical, Military & 9v

• Silver Oxide (Ag2O) - Coin Cells & Organizers

Secondary Cell Batteries

A battery that is rechargeable and used many times.

• Nicd/Nimh – 1.25V

• Lithium Ion – 3.6V

• Sealed Lead Acid – 2.0V

Nickel-Cadmium (NiCad)

• Length of constant use between charges is less than two hours.

• Will only charge to the level at which the battery was last discharged. This is known as the “memory effect.”

• Life cycle of 750 to 1000 charges.

• Primary uses are portable 2-way radio and pager.

Nickel-Metal Hydride (NiMH)

• Known as the memory free battery, which offers higher capacity.

• Lasts 30% longer between charges than NiCad batteries.

• Life cycle of 500 to 750 charges.

• Primarily uses are cellular, camcorder and 2-way radio.

Lithium-Ion (LiIon)

• The newest and lightest batteries for laptops, camcorder and cellular.

• Life cycle of 500-750 charges.

• Currently the most expensive option on the market.

Sealed Lead Acid

• Batteries’ electrolyte is in gelatin form and is absorbed into the plates.

• Battery uses are UPS, emergency lights and camcorders.

• Batteries are 2 volts per cell so the common batteries are 4, 6, and 12 volt.

Voltage

• Lithium Cell  (Non-rechargeable)  1.5 Volts, 3.0-3.9 Volts

• Lithium-Ion  3.6 Volts

• Primary Cell (Non-rechargeable)  1.3-1.5 Volts

• Sealed Lead Acid/Gel Cell  2.0 Volts

• NiCad/NiMH  1.20-1.25 Volts

Proper Charging Techniques

NiCads - The initialization process should be slow and long. The battery should receive a slow, trickle charge for

as long as 16 hours, depending on capacity. This initial slow charge process allows for the new cells to form properly.

After initialization, a NiCad battery may be rapidly charged for the rest of its life.  Studies has shown that the life

cycle a slowly charged battery is generally longer than a rapidly charged battery.

Nickel-Metal Hydride - For Nickel Metal, the opposite is true. Because these batteries become hot while charging,

it is always best to rapid charge a Nickel Metal battery to prevent damage to the cells. For this you will need a

rapid charger.

Lithium-Ion - A Li-Ion battery should be charged at a set current level (typically from 1 to 1.5 amperes) until it

reaches its final voltage. At this point the charger circuitry should switch over to constant voltage mode. The

charger must be capable of providing stable control loops for maintaining either current or voltage at a constant

value, depending on the state of the battery.