Note: Some GMDSS hand-held VHF radios com with a five-year (or similar) sealed lithium battery with an expiry date - just like an EPIRB or SART battery. That type of battery should not be used with the VHF radio for every day use, or your equipment willno longer meet SOLAS requirements. If the battery is used for some emergency or other, the date of first use should be recored and a replacement obtained at the first opportunity. A new, unused battery should supply your GMDSS hand-held radio for up to eight hours.

Other hand-held VHF/UHF radio, supplied for onboard communications , use rechargeable Nickel Cadmium (Ni-Cd) batteries. In some equipment, the hand-held set itself is kept in a charging unit when not being used. With others, the individual batteries are removed from the radio for charging. A typcal recargeable battery will supply your hand-held radio for around six hours. Some types of battery can suffer memory effect, which means  that they must be fully discharged before recharging - or they will "forget" how much capacity the should have. . The effect of recharging before discharging is that you reduce the time that battery will supply your equipment. Manufactures  instructions should be followed regarding use and charging of all portable equipment batteries.