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Best Battery Buying Guide

Battery technology is rapidly expanding from a “use it until it’s used up” structure to rechargeable batteries you can plug in and pick up the next day.

However, in a world where everything from your television to your fireplace has a remote, keeping up on rechargeable battery technology is important!

Types Of Batteries

All batteries work by making contact at the connections at either end of the battery. Inside the battery is a product which, when it comes in contact with the activated connections, produces a current and generates power.

  • Disposable: If the battery can only discharge power but never accept power, it’s disposable.
  • Rechargeable: If the battery allows a reversal of power (such as in your cell phone or laptop) it’s rechargeable.

What Are Alkaline Batteries?

An alkaline battery is a consumable source of power. Once it’s used up, it needs to be carefully discarded. Alkaline batteries generate power from a liquid or gel source.

Are alkaline batteries rechargeable? No.

If you’ve ever had an alkaline battery corrode inside an old radio and found a gooey mess inside the battery slot, it’s because the batteries leaked the gel catalyst that generates the power.​

Types Of Rechargeable Batteries

Nickel-Cadmium (NiCd) and Nickel-Metal Hydride (NiMH) Rechargeable Batteries

These batteries are often used in cordless power tools and can be found in electric cars. The fundamental difference between an NiCd vs NiMH battery is the material in their charging cells.

NiCd batteries receive via a wet charge, so once the fluid runs out, the battery ceases to function. This limits their life and functionality.

Cadmium is a heavy metal and is highly toxic, so NiMH batteries also offer a more environmentally friendly option.

Most NiCd battery installations have been replaced with NiMH batteries.

NiMH batteries can last up to twice as long as a NiCd battery because they will accept more recharges over the life of the tool you’re powering.

Rather than needing to transfer power through a wet cell, the charging cells inside a nickel-metal hydride battery are composed of metals and metal oxides.

They can accept a complete charge at any point in the discharge cycle and are less impacted by over-charging than nickel-cadmium batteries.​

Lithium Ion (LiOn) Rechargeable Batteries

Lithium ion batteries are often found in laptops, cell phones, personal music players and robot vacuum cleaners. These batteries do not suffer from over-charging, though they can age and fail over time.

charging cell phone battery

Avoid completely discharging them at all costs; this often ruins the battery.

They’re also very sensitive to heat. Because the charging cells in a lithium ion battery are formed of lithium and carbon, these batteries are extremely lightweight.

How do lithium ion batteries work? They distribute and receive energy via the positive electrode (made of lithium cobalt oxide) and the negative electrode, made of carbon.

These materials are wrapped in tight layers inside a metal casing, and these metal cases are lined up in series inside your battery to produce consistent power.​

Lithium Polymer Rechargeable Batteries

Lithium polymer batteries function with a polymer-infused electrolyte substance to generate and store power. This conducting tool works well in very small or thin applications such as battery powered credit cards.

When reviewing the lithium ion vs lithium polymer debate, it’s important to remember that lithium polymer batteries are currently up to 30% more money to produce.

While they work well in certain unique applications, they haven’t yet been standardized to size.

Why Get Small Rechargeable Batteries?

While many smaller batteries are not yet available in rechargeable format because it’s simply more cost effective to dispose of them, there are applications in which you’d want to use a rechargeable AA battery or AAA battery.

For example, they’re built into solar rechargeable landscape lighting, and can last for years depending on the conditions they’re exposed to.​

How Well Do They Work?

In power hungry tools such as pet monitors and digital cameras, rechargeable nickel-metal hydride batteries can save users a lot of batteries and will pay for themselves over time.

However, rechargeable NiMH batteries do lose power over time via trickle effect and should never be used in applications such as smoke alarms.

While disposable battery types may seem wasteful, these batteries do not suffer the trickle effect and will not fade away over time like a nickel-metal hydride battery.

How Long Do Rechargeable Batteries Last?

All rechargeable batteries age with time. Leaving them in the package will not protect them from this aging process; once they’re constructed, the aging process begins.

How do rechargeable batteries work? Once charged, the electronic device can be used until the battery is low.

Lithium ion batteries, lithium polymer batteries and nickel-metal halide batteries can all be charged at any point in the energy discharging process, and lithium batteries cannot be damaged by long-term charging.​

While nickel-cadmium batteries need to be nearly fully discharged prior to recharge, both nickel-metal hydride batteries and lithium ion batteries can be recharged at any point in their usage.

No rechargeable batteries are happy if they are run completely to zero, and ambient heat is destructive to all kinds of batteries.

Freezing Batteries

Keeping batteries cold reduces the rate of power loss through the trickle effect. Alkaline batteries don’t lose much power via trickle effect, so freezing them provides only a small benefit.

However, NiCd and NiMH batteries lose power much more quickly, so freezing them also freezes the rate of self-discharge.

Per authorities with Green Batteries charged NiMH and NiCd batteries will maintain a full charge longer if frozen. If you own a tool that uses NiMH and NiCd batteries, try freezing them once they’re charged.

Bring them back to room temperature before inserting them in your electronic device, and review the remaining power available. Storing batteries in a cool place is always a good idea, whether alkaline or rechargeable.​

Battery Comparison

There are some applications that are particularly suited to alkaline batteries.

As previously stated, you should never use a rechargeable battery in a smoke detector because those batteries lose or leak power much more quickly than an alkaline.

Other battery comparisons must be taken on a case by case basis.

Lithium vs Alkaline

Most lithium ion batteries are built to a specific size and location, so replacing them with alkaline batteries would be nearly impossible.

While round batteries may indeed run your laptop, they live in a sealed case that should not be tampered with!

LiPo vs NiMH

Lithium polymer batteries are also built to very specific configurations and can be used in extremely small settings.

While NiMH batteries have been the standard for hobbyists and fans of remote control toys, LiPo battery packs are making a footprint in that industry.

Per battery authorities at Roger’s Hobby Center, at this used point in battery technology development, LiPo batteries are less than ideal for this application.

They survive fewer charging cycles and are not very durable, making them ill-equipped for rough handling.​

NiMH vs Lithium

You can buy batteries for several power tools in NiMH or lithium configuration. While lithium batteries can hold and thus deliver more power, these batteries may require a new charger.

However, if you tend to store your power tool batteries in the charger, a lithium ion battery is a good choice. NiMH power tool batteries can be damaged by overcharging.

If you already have NiMH batteries for your power tools, investing in new batteries and a different charger may not be worth the money. If, however, your NiMH batteries have gone to recycling and you need to replace them.

You’ll enjoy a much longer battery shelf life with a lithium ion battery.

Shelf life can be calculated via a mAh battery life application, which calculates the battery capacity in milli amps per hour divided by the load current in milli amps per hour.

Functionally, you’re measuring how much power can be stored by how much current can be produced. Some tools will not run at all if the battery drops below a certain level of power, so this calculation is worth the time.

NiCad vs Lithium Ion Batteries

NiCad is another name for nickel cadmium batteries. These batteries were often included with rechargeable tools.

However, this battery configuration tends to require a deep discharge. Additionally, they can be ruined by running them out of power.​

Which Battery Lasts The Longest?

This question is highly dependent on application.

Lithium Ion Batteries

If you need a rechargeable battery that can be stored in the charger until you need it, you want a lithium ion battery.

How long do lithium ion batteries last? They will start to decay as soon as they’re built and will be unusable in approximately three years.

Are lithium batteries rechargeable? Yes.

Are they often formulated and constructed to fit in your electronics? Yes.

Many times, you have no other choice than a lithium ion battery.

Do lithium batteries leak? They will lose a little power at rest, but not as much as a NiCD or NiMh. When they are old, they’ll swell.​

NiCd or NiMH Batteries

These batteries can be found in an AA, AAA or 9v battery configuration. While they lose power more quickly than an alkaline battery, you can reduce this loss by storing them in a cold place.

Alkaline batteries

Disposable batteries will lose a small amount of power over time if they sit in a drawer for years on end. While it may seem a better buy to get batteries in bulk packages, they will lose some of their oomph before you can put them to use.

For example, how long do AA batteries last? An alkaline AA battery left in a drawer will lose 2 to 4% power over the course of a year.

Once it’s put into an electronic device, use will determine the overall length of life.

Extra Hazards To Consider

Heat and cold are extremely hard on batteries and electronics. While freezing some batteries can reduce their power loss, never insert frozen batteries into an electronic device.

Condensation around the frozen batteries can quickly destroy your electronics.

Additionally, if using a laptop, be sure to keep it on a surface that allows the battery to release heat. If you’re cuddled up on the sofa using your laptop, you can quickly cook a lithium ion battery and render it useless.

Never leave an electronic device in a hot or cold car, and if you must, let the device come to room temperature before powering it up.​

Cutting The Cord

Battery-powered technology gives us a great deal of freedom, and a whole new branch of electronics including personal audio devices such as iPods and MP3 players are built to travel and function away from their charging source.

Technology is continually leapfrogging in that as portable power sources become more effective, new devices that need even more electricity come onto the market. The only constant in the latest battery technology is change.​