What type of batteries do two-way radios use?
Lower-end FRS/GMRS walkie-talkies might use AA or AAA batteries, but most two-way radios use one of 3 types of batteries: NiCad, NiMH or Li-Ion.
Ni-Cad or nickel-cadmium batteries have been around the longest. They have a long life expectancy and are less prone to the problems associated with overcharging. They are the cheapest battery chemistry of the three. However, they are also the heaviest and tend to be susceptible to 'memory burn.'
Memory Burn occurs when a battery is recharged before it's fully discharged. The battery will 'remember' the partial charge and only fill up that far the next time it is being recharged. This shortens the power potential of the battery to that smaller, partial amount. To avoid memory burn, it's best to fully discharge your batteries before recharging them. If proper care is taken, Ni-Cad batteries can last 2-3 years.
Nickel Metal Hydride batteries share some chemistry with Ni-Cad batteries, but don't share their vulnerability to memory burn. Nickel Metal Hydride batteries are a bit more expensive and are more susceptible to overcharging issues, but they are smaller and lighter. They typically last 1-2 years.
Li-Ion batteries are the most expensive of the three. They don't get memory burn and are the smallest and lightest of the bunch. However, they are limited to a specific number of charging cycles and once that number is reached (500, 750, 1000) they won't take another charge. Also, their advanced chemistry means they require a special type of charger, but it can have them up and running in as little as an hour. Batteries are built on a basic calculation of 5/5/90. Battery manufacturers assume the battery will have a duty cycle of 5% talk-time, 5% listening time, 90% standby. References you may see as to the battery duration of X number of hours are typically based on the 5/5/90 assumed usage.
BATTERY LIFE: STAY SAFE OUT THERE!
Hardcore hikers, workers in remote locations, workers using heavy talk-time, or people working for more than an 8-hour shift should review and carefully consider battery life when buying two-way radios. You don't want to get cut-off from communications if your battery dies. If you live and work in remote and/or heavy battery use situations, you will want to have additional, fully charged batteries handy. When things get crazy, waiting to charge your only battery is not what you want to be doing.
It's important to note that the higher the wattage of your walkie-talkie, the more quickly it drains power. Look for two-way radios that switch to a power saver mode in between broadcasts. Most radios offer a battery indicator light or meter to signal how much power is left. Some vibrate or emit a low tone when battery levels drop. Another good feature to look for if your walkie-talkie uses a Ni-Cad battery is a rapid discharge button. Rapid discharge helps condition your battery, to avoid memory burn and extends its life expectancy. The two-way radio reviews and articles available on this site will help you determine if any of this is a danger.
Walkie-talkies used on a job site work well with built-in rechargeable batteries that are charged overnight. An overnight charge usually allows the radio to run for a full shift depending on the age of the battery.