It is not a good idea to mix new and old batteries

 

What do you do when the batteries in your electronic device finally give out? Do you replace each and every battery in it? Or do you only replace one battery, hoping that it will save you money in the long run?

If you’ve chosen the latter, you’ve made the wrong decision. Mixing old and new batteries doesn’t save you money; in fact, it could cost you more money and potentially damage your device!

Batteries are rated by their capacity, or the quantity of electricity delivered. Battery capacity is usually expressed in ampere-hours (Ah) or milliampere-hours (MAh). When mixing a new battery at full capacity and a used battery at a diminished capacity can cause harm to the batteries or the device. Let’s look at an example.

Suppose your pocket radio took two AAA batteries to run. You’re relaxing in the backyard listening to the ballgame when the radio suddenly dies. You go inside and search through the supply cabinet for a new pack of batteries. Thinking nothing of it, you pull out one dead battery and replace it with a new one.

It may look like there’s no problem on the outside, but on the inside, your radio is going through power faster. Chances are, your radio’s power circuit has the batteries connected in series. When this happens and a new battery is mixed with the old, the voltage increases, but the capacity remains the same. If your radio’s power circuit is connected in parallel, then the capacity increases, but the voltage stays the same. Some devices even contain a sensor to halt operation when voltage drops to a certain level. Devices require a certain voltage to function, and their lifespan is determined by a battery’s capacity. Shortchanging either only causes your device to fail faster.

In other words, your new battery isn’t functioning at its maximum potential because the old battery is dragging it down. Think of your batteries as tires on a car. Car tires generally have a running life of a certain number of miles. If one tire is older than the others, then it will inevitably fail quicker than the others. When it fails, there is further stress placed on your other tires until you have the opportunity to replace it. And if you only replace that one failed tire, the other three will most likely need replacing relatively soon. While it may seem like you’re saving money and time by only replacing one tire, you’ll actually wind up spending more of both by eventually replacing each individual tire.

Let’s look at a twist at our example. If your radio was powered by rechargeable batteries and had a low voltage detector, then the radio would die before either battery could be fully drained. If your radio did not have a low voltage detector, then one – or both – of your batteries runs the risk of being over-discharged. Over-discharging occurs when a rechargeable battery continues to be tapped for power after it runs out of voltage and capacity. After over-discharging, the battery’s polarities are reversed and it cannot be recharged. Furthermore, an over-discharged battery runs the risk of exploding.
Certain battery chargers face the same risks when mixing newer and used batteries. Battery chargers come in either series or parallel circuits. Series circuits run the batteries in line through the same charge channel. Since the newer battery and the older battery use the same channel, they are continuously charged until both reach capacity. In this case, the newer battery becomes over-charged. Over-charging a battery causes damage by increasing internal pressure and causing internal chemical leakage. This leads to decreased capacity.

Whether you’re using single-use or rechargeable batteries, it’s recommended that you do not mix old and new batteries. Your device will run longer, you’ll save money, and you’ll avoid the risks that come with mixing batteries. For more information, contact the experts at AmondoTech or visit AmondoTech discussion forum.

 

Source AmondoTech.Com