Batteries:

 Battery voltage (V) is determined by the number of cells in the battery pack. Multiply the number of cells by 1.2 volts to get the pack's voltage, e.g. 7 cells X 1.2V = 8.4V, 8 cells X 1.2V = 9.6V. The amount of voltage determines the rate of fire of the gun and how strong a spring you can install in the gun.

 Battery milli-amperage (mah) should be printed on the battery cells. The amount of mah indicates how long you can fire your battery-powered gun for, and how long you will need to charge your battery.

  There are two types of rechargeable batteries suitable for Airsoft electric gun usage, nickel cadmium (NiCad) and nickel metal hydride (Nimh) batteries. The following is a comparison between the two battery types:

A nickel-metal hydride cell, abbreviated Ni-MH, is a type of rechargeable battery similar to the nickel-cadmium cell. The Ni-MH battery uses a hydrogen-absorbing alloy for the negative electrode instead of cadmium. As in Ni-Cd cells, the positive electrode is nickel oxyhydroxide (NiOOH). A Ni-MH battery can have two to three times the capacity of an equivalent size nickel-cadmium battery. Compared to the lithium-ion cell, the volumetric energy density is similar but self-discharge is higher.   

 Never pull batteries by their plugs and be careful not to damage the wiring insulation.

 Exposing the battery wires to contact with another battery wire or other metallic objects can cause the battery to short out and create a potential fire hazard.

 Unplug batteries from your Airsoft gun whenever it is not in use.

 Store batteries in a cool, dry place when not being used.

 Never expose batteries to open flame or break open the cells.     

 Be sure to dispose of batteries in the proper manner.

Charging batteries: 

*WARNING*: Do not overcharge batteries! If they overheat, you could cause damage to the battery and create a potential fire hazard!

Be sure to read the charger instructions thoroughly before charging your battery. 

Not all chargers are created equal. Please use the proper charger, which is intended for your battery type, i.e. if you are charging a 9.6V Nimh battery, be sure your charger can charge 9.6V batteries and Nimh batteries.

Be sure to use the proper connectors to connect your battery to the charger.

Calculate the proper amount of time required to charge a battery by dividing the battery's milliamp capacity by the chargers charge rate, e.g. it would take a 250 mah rate charger 6 hours to charge a completely drained 1500 mah battery. Every charger is different, so be certain to read your chargers manual thoroughly before charging your battery. 

If you are not certain of a battery's remaining charge and you wish to charge it, place the battery on the charger and check it every 5-10 minutes. If the battery is warm to the touch, assume it is fully charged. If it is hot to the touch, remove the battery from the charger immediately! ·

 Remember, NiCad batteries must be completely discharged before charging again. Use the appropriate discharger to discharge the battery, or completely drain the battery through normal use before charging again.