It's important to know which type of battery your walkie-talkies are using. Some walkie-talkies use AA or AAA batteries, but most two-way radios are powered by one of three types: NiCad, NiMH, and Li-ion. Ni-Cads (Nickel-Cadmium) are long-lasting and less likely to overcharge and overheat the battery. However, memory burn is a common issue with these batteries. It occurs when you recharge them before they are completely drained, and this damages the memory of your battery, so it lasts for shorter periods than usual. To avoid this problem, always let batteries fully discharge before recharging them again. NiMH (Nickel Metal Hydride) batteries offer many benefits over their Nickel-Cad counterparts, such as being more resistant to memory burn and not suffering from the long-term effects. However, these advantages come at a price. NiMH's typically last 1-2 years before needing replacement. The Lithium-ion battery is the most expensive of all three types and has a limited number of charging cycles. Once it reaches for example 500 or 750 charges, you'll no longer be able to charge them. Therefore, these battery types need specific chargers.