5 Devices You Should Never Put Rechargeable Batteries In

Rechargeable batteries are becoming increasingly popular, and for the right reasons. They are more powerful, economical in the long run, and easier on the environment. However, there are household devices that still need those good old disposable batteries. Using rechargeable batteries with these isn't just counterproductive but may also affect the device's functionality and lifespan. There are two main reasons for that. First, and most important, rechargeable batteries have a higher self-discharge rate. This means, even when not in use, the battery will steadily discharge and run out of power sooner than single-use batteries.

The discharge rate largely depends on the chemical composition inside the battery. For instance, NiMH (Nickel-Metal-Hydride) rechargeable batteries have a higher self-discharge rate than NiCD (Nickel-Cadmium) counterparts. Second, commonly available rechargeable batteries have a lower voltage rating of 1.2V compared to single-use alkaline batteries that can deliver 1.5V. So, many devices that require a 1.5V supply may either malfunction or fail to work with rechargeable batteries. Now that you know the common limitations of rechargeable batteries, it's time to find out devices for which they are generally not a good fit.

Security and smoke alarm systems inside your house are critical devices. They run for months without coming into use, but when the need arises, you expect them to work instantly. That's why rechargeable batteries are a poor choice for these due to their high self-discharge rate. If you use rechargeable batteries in alarm systems, they may lose power after a few months, much sooner than disposable batteries. Another reason is that these are low-energy devices, making single-use alkaline batteries a better choice.

Rechargeable batteries, on the other hand, are more suited for devices where more power directly translates into better performance, like game controllers. Keep in mind that for devices like smoke alarms and security systems, it's best to refer to the product's user manual before picking a battery. Some models even ship with built-in lithium batteries that can last for up to a decade.

Wall clocks don't need rechargeable batteries because they consume little power, something an alkaline battery can easily handle. Then, wall clocks are often hung at a height, making access slightly challenging. So you would naturally want something that runs longer, not one that loses power in a few months. With rechargeable batteries, you would have to charge them more frequently, which means you'll have to reach out to your ladder sooner than you would want to.

Then there's the cost factor. Rechargeable batteries, despite being more expensive, turn out to be a more cost-effective option because they can be recharged hundreds of times. But this only works out if they are recharged more frequently, say once every month or so, and not once every two years. With the latter, it will take much longer to recover the higher upfront cost. So, you are better off using non-rechargeable, single-use alkaline batteries in wall clocks, both from a practical and cost standpoint.

Remote controls for TVs, ACs, and similar devices use very little power. Most of the time, the remote is not even in use, sitting in a corner of the house. If we were to use rechargeable batteries here, they would lose charge over time, irrespective of how frequently the remote control is used. Additionally, remote controls may show incorrect charge levels with rechargeable batteries, since they detect battery health based on voltage curves. And since rechargeable ones operate at a lower voltage level, some remote controls, especially the ones calibrated for alkaline batteries, may show inaccurate battery charge.

Apart from that, the cost factor applies here too, making rechargeable batteries an impractical option for most. If a device runs for six months to a year without needing battery replacement, you should prioritize non-rechargeable batteries for those. Because the inconvenience of regularly recharging the battery far outweighs the little cost savings you may see in the long term.

Backup or emergency lights are another set of devices that don't benefit from rechargeable batteries. These are usually used once or twice a year, and you expect them to work instantly. Rechargeable batteries have a high self-discharge rate and experience faster voltage drop, making them unreliable for backup lights. With alkaline batteries, the voltage drop is gradual. So, even at low charge levels, they can power up emergency lights and flashlights.

For anything that sits idle for weeks or months, single-use alkaline batteries are a better choice over rechargeable batteries. With the former, the emergency light or flashlight will gradually dim as the battery level falls, but with rechargeable batteries, they may suddenly turn off when needed due to the steeper voltage drop. Keep in mind that some emergency lights ship with built-in rechargeable batteries, in which case, you can continue using them, as that's what the manufacturer recommends.

Most older battery-powered devices were designed for non-rechargeable, single-use batteries. This includes a wide array of electronic toys, like RC cars and their controllers, and even some camera models. In simple terms, they need the 1.5V output of alkaline batteries as opposed to the 1.2V of rechargeable ones. With the latter, the device may malfunction or not turn on at all. It's best to check the product's manual for the recommended battery type. If it says alkaline, switching to rechargeable batteries may not be a smart choice.

As you can see, not every device benefits from rechargeable batteries, primarily because of the high self-discharge rate, lower voltage rating, and the steep voltage drop. The list above isn't exhaustive, but it should give you a good idea of where rechargeable batteries may not be the best choice. With the right batteries, you get more convenience, better performance, and longer device life.