Yes, they are finally available. However, only a few Chinese companies manufacture them. These batteries are AA and AAA rechargeable lithium polymer batteries that output 1.5 volts.

• Tenavolt Lithium-Ion AA Batteries (2775 mWh)
• Deeleepow Lithium-Ion AA Batteries (3400mWh)

Lithium-ion batteries normally operate at 3.7V per cell. The circuitry inside the cells reduces the voltage to 1.5 volts. The batteries have a capacity of 3400mWh, which matches Eneloop Pro (NiMH batteries with the highest capacity). Additionally, lithium-ion cells are lighter than NiMH cells.

Other Lithium-Ion Rechargeables

There are also some lithium-ion rechargeable batteries made for high-performance flashlights and cameras in these sizes: 18650 and CR123.

A single 18650 battery can replace two CR123A batteries, although at a lower voltage (but much higher amperage). However, the 18650 is a wider cell and will not fit into a flashlight designed strictly for the narrower CR123As. Most modern tactical LED lights are designed to use a single 18650 or two CR123As, but it’s best to check before buying. See our article on The Best 18650 Batteries for more information.

There are also numerous other types of lithium-ion batteries made for specific laptops and other electronic gadgets. There is currently no standard size for these lithium-ion cells.

The post Do Rechargeable Lithium-Ion AA Batteries Exist? appeared first on Reactual.

Panasonic’s Eneloop Pro AA Batteries.

These are made with Nickel-Metal Hydride (NiMH) chemistry and have low standard discharge, meaning they can hold a charge for years.

AmazonBasics AA High-Capacity Rechargeable Batteries are a reliable low-cost alternative. They are about 30% cheaper than Panasonic cells, but last only 75% as long per charge.

The Details

Panasonic eneloop pro batteries are high-capacity lower-cycle AA battery popular with electronics reviewers and photography enthusiasts. First launched back in 2006, Sanyo eneloop batteries (since acquired by Panasonic) use eco-friendly NiMH cells designed for use with a wide-variety of products, ranging from flashlights to cameras. Up until the eneloop’s debut, rechargeable batteries were prohibitively expensive and couldn’t hold a charge for anywhere near the length of their alkaline competitors.

Eneloop changed that, but still lacked a little when compared to alkaline batteries or newer competitors. Panasonic’s upgraded option, eneloop pro, can maintain a charge for an extended period of time, with a capacity of 2,550 mAh and Low Self Discharge (LSD) technology. LSD tech is thanks to a highly-durable super lattice alloy that prolongs battery life with increased hydrogen stability that leads a stable voltage output and reduced self-discharge. Expect an eneloop pro to still have 85% of its charge after a year and 70% of its charge for ten years.

What really sets eneloop pro apart is the increased performance in high drain devices, such as DSLR cameras and ultra-bright flashlights. Eneloop pro lasts longer and omits more power in these high power consumption devices when compared to similar NiMH rechargeable batteries on the market. Simply put, these are the best choice for photographers and survivalists.

The added power comes at a payoff, however. Eneloop Pro batteries are among the most expensive NiMH batteries on the market, and last for fewer lifetime charges. Panasonic estimates that an eneloop pro can be recharged 500 times, but number is even lower in reality. Compare that to Powerex’s Imedion AA, which boast 1000 recharges.

Another Option

AmazonBasics offers pre-charged high-capacity NiMH batteries for an affordable price. They are rated at 2400mAh, giving them a longer run-time than similarly priced competitors. They are ideal for everyday uses in low drain devices, like TV remotes and electronic alarm clocks.

Wirecutter found that AmazonBasics did not perform as well in high power devices, such as flashlights and digital cameras.

The post The Best Rechargeable AA Batteries appeared first on Reactual.

The Details

Ultraviolet light is the preferred light source of TV crime scene investigators on the hunt for body fluids. Distinguished by its trademark purple glow, it has a wavelength that is shorter than visible light but longer than X-rays, in the range of 10 nanometers to 400 nanometers. It is useful to make fluorescent substances glow that can’t otherwise be seen by the naked eye. Portable UV light used to be too unwieldy and expensive for consumer purposes, but that all changed after ultraviolet light emitting LEDs were introduced in 2006. They are now widely available in flashlight form.

These flashlights are most often used to detect fraudulent documents such as fake IDs, see watermarks, read invisible ink or investigate crime scenes. They can also be used to “fluoresce” scorpions and certain types of minerals, and charge “glow-in-the-dark” object like fishing lures. Use them to protect your businesses from counterfeit money and your home from pointy tailed pests.

Gallium Indium Nitride UV Flashlight

This Gallium Indium Nitride UV flashlight gets great ratings from Amazon buyers, so we thought we’d include it here. Reviewers were impressed by the flashlight’s durability, and the fact that it emits 365 nm UV light, which is at the very edge of our visible range. The light from this flashlight appears as a dim purple-blue to the eye, but when it shines on items that fluoresce they light up brightly.

It uses three AAA batteries — we recommend using low self-discharge AAA rechargeable batteries like Eneloop Pros in this flashlight.

The post The Best Ultraviolet LED Flashlights appeared first on Reactual.

This headlamp weighs just 1.1 oz (32 grams), or 2.9 oz (80 grams) with an AA battery and headband. This makes it a great choice for a runner or night hiker.

In most cases, you’ll want to use the 116-lumen “medium” mode — this is quite sufficient to light up a trail at night. The Zebralight H52 lasts about three hours in this mode, when using a rechargeable NiMH batteries like the Eneloop Pro. The headlamp is also capable of accepting a 3.7V 14500 lithium-ion rechargeable battery.

When in high mode (300 lumens mode) it lasts about 40 minutes. In low mode it outputs 27 lumens — this enough light to read a book in bed for example.

The maximum beam length is 66 meters.

The Zebralight H52 is waterproof to IPX7 — this means it can be submersed for 30 minutes at a depth of 1 meter. This is due to its unibody aluminum casing.

Here are some more nice features on this headlamp:

• A battery capacity indicator (LED flashes 1-4 times)
• Automatic stepping down to lower output when battery (AA and 14500) capacity is low
• Over-discharging protection for 14500 batteries at 2.8V cutoff

You can find the Zebralight H52 (Cool White). on Amazon for about $74. Also available is the 280 lumen Neutral White (this version has 20 fewer lumens but a slightly warmed light).

The post The Brightest Single AA Headlamp (300 Lumens) appeared first on Reactual.

• Kentli makes the best rechargeable lithium-ion AA batteries currently available. They are rated at 2800mWh, and are the only 1.5 V li-on AA batteries, making them the best choice for consumer-grade electronics.
• EXCELLENT makes 3.7V li-on batteries compatible with high drain devices like LED flashlights.

The Details

Not long ago, disposable alkaline batteries enjoyed an undisputed mastery of the AA battery market. Improvements in rechargeable battery technology upended that dominance over the past decade. As we reported in this article, Nickel-Metal Hydride (NiMH) AA batteries such as Panasonic’s Eneloop have made rechargeable options more cost-efficient in the past 10 years.

A 1.5V lithium ion battery has recently been made available to consumers. Lithium ion cells have a high energy density, long cycle life, and have a lower self discharge rate than NiMH batteries. In other words, they last longer and maintain a more even voltage than other types of cells.

Kenli’s 1.5V offering is an ideal choice for everyday household needs. The batteries have the same voltage as a brand-new alkaline battery and won’t overpower devices that just need a stock battery.

2800mWh is a respectable capacity, equivalent to around 1866mAh. By comparison, the Eneloop Pro has a capacity of 2550mAh. Like most NiMH batteries, the eneloop pro is 1.2V.

This equation explains the difference between mWh and mAh:

miliWatt x Hour = Volts x miliAmpere x Hour or mWh = V x mAh. For more on the conversion process, read here.

Other Options

Higher voltage lithium-ion rechargeable batteries are made for high-performance flashlights and cameras, but they are not intended for use with many products. They are higher energy density and rated at 3.7V.

EXCELLENT is one company producing higher energy density lithium ion batteries. Their 18650 batteries have a 2600mAh capacity and high quality cells. They are 3.7V and great for UV or high powered LED flashlights that consume a lot of energy.

One word of warning too consumers: there is currently no standard size for these lithium-ion cells. Make sure to read the dimensions of each battery on Amazon before you buy to guarantee that they will fit in your device.

The post The Best Lithium-Ion AA Batteries appeared first on Reactual.

• If you want the best energy capacity (2550 mAh) — get the Eneloop Pro
• If you want maximum recharge capacity (2100 times) — get the 4th Generation Panasonic Eneloops

Overall, the best rechargeable AA battery is the Eneloop Pro. They have a high energy capacity (2500 mAh), and they perform better than similar high-capacity AAs. They can only be charged 500 times (versus 2100 times for regular Eneloops). But most people will never charge their batteries that many times. For example, if you charged your batteries twice a week consistently, it would take 5 years to reach 500 charges.

Sanyo Eneloop

Top Review Sources:

• Consumer Reports: Recommended
• Doc’s Charger and Battery Reviews: “Good performance for a 2000 mAh rated battery, and fantastic shelf life for a Ni-MH”
• Amazon: 4.5/5.0 (1,600+ reviews)

Eneloops are currently the top rated rechargeable AAs, and we have found them to perform well.  We should also mention Imedion batteries, which are similar to Eneloops but rated at 2400 mAh (this stands for milli Amp hour, and indicates a battery’s energy storage capacity). Eneloops, by comparison, have a lower rated capacity — 2000 mAh (or 1980 mAh according to my informal tests).

You’ll find the Sanyo eneloop AA four pack ($11) on Amazon. You can also buy an eneloop AA four pack with included recharger ($18) as well as an eneloop AA eight pack ($20).

Eneloop Pros

The Eneloop Pro is a high-capacity version of the regular Eneloop cell. The Eneloop Pro has a capacity of 2500 mAh –this is 500 mAh more than the regular Eneloops. Their only potential downside is that they can be charged 500 times — not 2100 times like the regular Eneloops. However, on average most people will charge their batteries about 100-200 times over a 5 year period.

Eneloop Pro batteries are available on Amazon.

Energizer Ultimate

Pros:

• Great for high-drain devices and maximum runtime
• Fantastic shelf life

Cons:

• Not rechargeable

Top Review Sources:

• Consumer Reports: Recommended
• Amazon: 4.5/5.0 (150+ reviews)
• CHOICE Online (Australia): “The ENERGIZER e2 Lithium was by far the top performer in our test”

The Energizer Ultimate is a disposable battery meant for high-drain devices and long periods of time away from another power source. It is the successor to the similar Energizer e2. Like the e2, the Ultimate is a lithium battery. One of lithium’s advantages over other types of batteries is a longer runtime. The Ultimate AA is a 3000 mAh battery that operates at about 1.7 volts; it is able to energize a high-drain device (such as a powerful camera) for a longer period of time than most other batteries. If you have a gadget that needs the higher voltage, or if you need a battery that will last in a high-drain device for as long as possible, lithium is a great option. Another lithium advantage is its 10+ year shelf life, making it a good backup battery to have around for emergencies. Lithium batteries also operate in sub-freezing temperatures, unlike alkaline disposables.

The Energizer Ultimate four pack ($5) is available on Amazon. Also for sale is an eight pack ($15).

Duracell CopperTop

Pros:

• Low initial cost
• Long shelf life

Cons:

• Not long-term cost-effective

Top Review Sources:

• Amazon: 4.5/5.0 (125+ reviews)
• PC Magazine: Longest runtime in flashlight test (of seven batteries tested)
• CandlePowerForums.com Alkaline Battery Shoot Out: 4^th place (of 19 batteries tested for watt-hours)

Duracell CopperTop batteries use alkaline technology to deliver reliable performance at a low cost per battery. While rechargeable batteries will save you money in the long run, disposable alkalines like the CopperTop have advantages such as lower initial cost and longer shelf life (7+ years). CopperTops are not suited for high-drain devices; they won’t last as long as NiMH or lithium batteries. However, if you use batteries very infrequently or need a long-lasting, inexpensive solution for a smoke detector or rarely-used remote control, the CopperTop offers a compelling price/performance balance.

The Duracell CopperTop 20 pack is for sale on Amazon.

See also our extensive review of rechargeable batteries and chargers on MetaEfficient.

The post The Top Rated AA Batteries appeared first on Reactual.