Batteries are a necessity; no portable device can work without batteries. It is frustrating to be out of battery and it usually happens at the worst time. Although battery technology has evolved over the years the batteries today are still quite limited in their capacity. In order to make sure you rarely find yourself out of battery it is important to understand what the different battery technologies are, what they mean to you and how you can get more out of your batteries.

There are two main types of batteries, disposable and rechargeable. Disposable batteries are used once and as their name suggested are disposed when they run dry. Rechargeable batteries on the other hand can be used over and over again by simply reloading them with energy in a process called recharging.

Rechargeable batteries use a variety of technologies. Their chemical ingredients used to build up the battery are different. Each technology has its advantages and disadvantages. The two main types of rechargeable batteries on the market today are NiMH (nickel metal hybrid) and Lithium-Ion. Any battery will have NiMH or Lithium-Ion written on it. The Sanyo 2700mAh NiMH as the name suggests is a nickel metal based battery.

One important different between nickel metal and lithium-ion that is good to remember is what is known as battery memory. Nickel metal batteries have what is called a recharge memory. Lets say that the battery is fully charged, if you use half of it and then recharge it the battery will not recharge to its fullest capacity. The way in which nickel metal batteries should be charged is by first discharging them completely empty and only then charging them. Many modern nickel metal charges will do that for you ? they will start by discharging. You should check if your charger supports that. If not it is usually good practice to just use the battery until it is empty or if you need to fully charge it to first just put it in the device, such as a camera, and just play with it until the battery runs dry. Lithium-ion on the other hand do not have a memory. There is no need to discharge them before they can be fully charged.

The other parameter printed on the battery is its capacity. For example the Sanyo 2700mAh NiMH capacity is 2700mAh. The capacity is measured in mAh which stands for miliamper hour. Miliamper is an electrical current unit. 2700 miliamper hour is a battery capacity that can supply 2700 miliamper for exactly one hour. So for example if your device consumers 1350 miliamper a 2700 miliamper hour battery can power it for two hours before it runs dry.

So what does it mean if your device requires four batteries? Is four batteries capacity four time each battery's capacity? The answer is yes and no. It depends on how the batteries are set up. In most devices the batteries are connected in serial since each battery supplies about 1.5V putting four in series supplies the needed 6V or so to run the device. When connected in serial the capacity of the four is the same as the capacity of one battery. When connected in parallel however the capacity is the sum of all batteries.

It is good to know your battery capacity for qualitative comparison ? if one battery has a bigger mAh number it will in principal last longer. It is however impossible to actually calculate how long that will be since the device consumption changes all the time ? it is not steady.

So to summarize the Sanyo 2700mAh NiMH is a nickel metal kind of battery and its capacity is 2700mAh.