Rechargeable batteries are more beneficial to both the environment and your wallet than standard batteries. But how do they work? If you’ve ever been curious about how rechargeable batteries work or why you should switch from standard, we’ve got you covered.
There are a few key differences between a rechargeable battery and its standard cousin, but the core process required for a battery to power a device is the same. Those few differences, however, make rechargeable batteries way more efficient, energy-conscious, and cheaper in the long run.
To understand how rechargeable batteries work, you first have to know how a standard (one-time use) battery works. If you already know how regular batteries work, you can skip ahead a little bit; if not, check out this short explanation.
Going back to very basic science, a battery, like everything else in life, is made up of atoms. Then, an atom is made up of particles called protons, neutrons, and electrons. Although it seems like protons, electrons, and neutrons were defined multiple times throughout grade school, here’s a refresher. Protons are positive particles, electrons are negative particles, and neutrons are neutral particles with no charge.
If you grab a AA battery and take a close look at it, you’ll see a positive symbol (+) on one end and a negative symbol (-) on the other. These positive and negative indicators represent a positive electrode and a negative electrode inside the battery, separated by an electrolyte solution that controls the electric current between both ends of the battery.
The positive electrode, called the cathode, has a positive charge because it has way more protons than electrons. Then, the negative electrode, called the anode, has a surplus of electrons that don’t match its number of protons.
Both the cathode and the anode want to get to a state of equilibrium where they have equal numbers of protons and electrons. To do this, electrons travel from the anode (the negative end) to the cathode (the positive end) using the electrolyte solution, which only lets electrons through when a battery is connected to a device.
When all the excess electrons from the anode have made their way to the cathode, the battery is dead and can no longer power any of your electronics. On the other hand, rechargeable batteries can use a charger to reverse electron flow so that the anode once again has a ton of electrons to give off and allow an electric current.
This electron reversal process allows rechargeable batteries to be used again and again. Now, that’s not to say that you can buy a pack of rechargeable batteries and have it last you for life. Just like your smartphone battery life gets worse over time, rechargeable AA or AAA batteries will lose their ability to hold a full charge. If you’re maintaining and using your rechargeable batteries properly, they can last you up to five to seven years.
Rechargeable batteries have to be made of certain elements, like lithium, to allow for a safe recharging process. Non-rechargeable batteries are typically called alkaline batteries, with zinc and manganese dioxide as electrodes and either potassium or sodium hydroxide as the electrolyte solution dividing the two. Alkaline batteries can’t be recharged and, in fact, can even be dangerous and sometimes explosive.
If you decide to invest in rechargeable batteries, you’ll need to be sure you get the right charger for the batteries you purchase. There are three main types of rechargeable batteries: Li-ion (Lithium-ion), NiMH (Nickel-Metal Hydride), and NiCd (Nickel-Cadmium).
Getting a NiMH charger for Li-ion batteries or any other mismatched combination is a bad idea. So be sure to recognize what your rechargeable batteries are made of and find a proper charger for that specific battery type.
There are both environmental and financial benefits to using rechargeable batteries in lieu of standard batteries. Because rechargeable batteries allow you to buy less of them over time, you’re creating less waste, both from dead batteries and packaging from new packs of batteries. Plus, although you have to spend a bit more upfront for rechargeable batteries, you’ll save money over time. All battery brands differ in price and estimated charge length, so let’s take a look at Duracell’s batteries for a closer comparison.
A 4-pack of Duracell’s Standard AA Batteries retails for about $6, while a 4-pack of Duracell’s Rechargeable Batteries retails for about $16. Then, you’ll also need to buy a charger for the rechargeable batteries, or you can snag a value pack with batteries and a charger.
While you’d save $10 right away by sticking with standard batteries, consider how much you’d save with rechargeable batteries over 400 total recharges. It’s impossible to know whether you’d get exactly 400 recharges out of each battery, but that’s what Duracell boasts its rechargeable batteries are capable of. If you’re recharging your batteries instead of buying new ones—400 times over—that’s a huge amount of money saved.
Don’t forget about the environmental implications either! With Duracell’s rechargeable batteries, that’s about 400 packages of standard batteries (and ~1600 actual batteries) that you’re saving from the trash.
Of course, these are estimates that are just there to suggest the possibilities. As mentioned above, every battery brand boasts a different number of recharges, a different price difference, and sometimes even different types of rechargeable batteries. Duracell’s 400 recharges guarantee is also likely based on properly maintaining your batteries over the years.
As mentioned earlier, make sure you purchase the correct type of charger for the kind of rechargeable battery you bought. For example, if you go with Lithium rechargeable batteries, make sure you buy a Lithium-specific charger. Although your batteries might charge in a non-Lithium charger, it’s not as efficient and certainly not as safe.
Speaking of chargers, try to get a smart charger that will prevent overcharging. Smart chargers recognize when the battery is full and either cut off charging or switch to trickle charging until you can take them out of the charger. Even if you have a smart charger, you should still take your batteries out when you realize they’re fully charged, or even better, almost fully charged.
Charging a rechargeable battery follows a lot of the same protocols as charging a smartphone. You might’ve heard that letting your phone die or overcharging your phone can lead to the battery losing its ability to hold a charge as well. The same concept can be applied to rechargeable batteries. It’s better if you charge them when they hit about 20% capacity rather than waiting until they fully run out of juice.
You’ll also want to constantly use your rechargeable batteries. Without fairly regular use, rechargeable batteries won’t be able to function as well. This might mean rotating out your batteries every month, even if they’re still at a 50% charge.
Make sure you monitor the heat of your batteries while charging, or better yet, get a smart charger that comes with some sort of cooling feature or heat-absorbing material. Heat is detrimental to rechargeable batteries, so be sure to also store them away from sunlight when not in use.
For the most part, yes. Rechargeable batteries will last you anywhere from two to seven years, depending on the brand you choose and how well you maintain them. They’ll save you money, help the environment, and they’re just cooler. Even without the recharging feature, rechargeable batteries typically last longer than standard batteries because of what they’re made of.
That said, there’s certainly nothing wrong with keeping both standard and rechargeable batteries on hand. After all, rechargeable batteries require power from an outlet to recharge them. So if you’re in the middle of an emergency, like a power outage from a storm, and your rechargeable batteries aren’t charged, you’ll be thankful for your stash of standard batteries. Alkaline batteries also have a significantly longer shelf life than rechargeable batteries, making them a better pick for emergency kits.
There’s another instance where alkaline batteries win out over rechargeable batteries. Alkaline batteries are the better choice if you have electronics that need a constant draw of low power, like a wall clock, bike light, or head lamp. These batteries start out at a higher voltage and drain at a consistently predictable rate.
Rechargeable batteries, on the other hand, start at a lower voltage and maintain that low output for longer, which can result in weird or inconsistent performance in a device. Also, rechargeable batteries lose total capacity the more times they’re recharged. So when using a device that’s constantly using power, you might find yourself recharging the batteries more often than you’d like.
It’s also worth thinking about what items in your home currently require batteries. Do you remember when the last time was you had to change the batteries in your remote? Many devices nowadays come with a built-in battery that recharges via a USB cord and a wall outlet. Before you get consumed with choosing between standard and rechargeable batteries, think about how much you use them in general.
If you want to make the switch and invest in some rechargeable batteries, we can help. We’ve done all the research for you if you just want to browse through our picks, but we also cover what you should look for in a rechargeable battery in case you want to search on your own.
Panasonic BK-3HCCA4BA eneloop pro AA High-Capacity Ni-MH Pre-Charged Rechargeable Batteries, 4-Battery Pack
Best Budget Rechargeable AA
Amazon Basics 4-Pack AA Batteries, High-Capacity 2,400 mAh Rechargeable Battery, Pre-Charged, Recharge up to 400x
Highest Capacity Rechargeable AA
EBL Pack of 8 AA Batteries 2800mAh High Capacity Precharged Ni-MH AA Rechargeable Batteries
Panasonic BK-4HCCA4BA eneloop pro AAA High Capacity Ni-MH Pre-Charged Rechargeable Batteries, Black , 4 Pack
Best Budget Rechargeable AAA
Energizer Rechargeable AAA Batteries, Recharge Power Plus Triple A Battery Pre-Charged, 4 Count
Highest Capacity Rechargeable AAA