The keyring contains the following elements:

• The LD01 Flashlight by Fenix (powered by a hybrid rechargeable AAA battery)
• The folding waterproof Inka Pen
• The 6-in-1 Key Ring Tool by Swiss+Tech
• An Emergency Cash Holder by Cash Can

Here are the details of the MetaEfficient Keyring elements:

The LD01 Keyring Flashlight by Fenix

Fenix Keyring Flashlight Powered by AAA Battery

Why It Was Chosen

The Fenix LD01 is the brightest keyring-sized flashlight that runs on a standard AAA battery. This means it can be powered by a hybrid rechargeable AAA battery. It produces 80 lumens of light on its highest setting.

The Fenix LD01 uses a Cree Q5 LED as its light source, and the lens is made of toughened, anti-reflective glass. It weighs 1.6 ounces, and it is “IPX-8 water proof” meaning it is suitable for continuous submersion.

The flashlight is RoHS compliant (meaning it does not contain non-toxic heavy metals or flame retardants).

It’s available for $35 from Amazon.

The Inka Pen

Why It Was Chosen

The Inka Pen is a keyring sized ball-point that can be used quickly as a half-sized pen, or unfolded into a full-sized pen. Using a pressurized ink cartridge, the Inka Pen is waterproof and write at any altitude or temperature. It’s made in the U.S. and has a lifetime warranty.

The “6-in-1 Key Ring Tool” by Swiss Tech

Why It Was Chosen

The “6-in-1 Key Ring Tool” is a keyring-sized multitool by Swiss Tech. It contains the following:

• straight knife blade
• a serrated cutting surface
• a micro-sized screwdriver
• a Phillips screwdriver
• an eyeglass screwdriver
• bottle opener

The tool weighs 0.5 oz. Given its size, it’s pretty basic, its handy when you have nothing else available, but not suitable for everyday tasks.

The Mini Cash Can

The Mini Cash Can: A Keyring Sized Emergency Money Consealer

Why It Was Chosen

The Mini Cash Can is an emergency cash holder than fits on your keyring. You can secret a single bill inside this stealthy container. If you forget your wallet, you have the cash inside as a back-up. The Cash Can’s assembly cannot accidentally come apart as long as the keyring is through the hole. The container is waterproof.

I actually found a little difficult to fit a bill inside the Mini Can — the larger Mini II might be a better choice.

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Today, the best rechargeable batteries are the new hybrid Nickel-Metal Hydride (Ni-MH) cells. These hybrid batteries have a lot going for them: they come fully charged (like alkaline batteries), and they can hold their charge over may months (unlike regular Ni-MH rechargeables). Because they can hold their charge for so long, they are suitable for low-drain devices like remote controls and flashlights. But they are also ideal for use in high-drain electronic devices like digital cameras.

So, basically, these new hybrid Ni-MH cells offer the convenience and shelf-life of alkalines, and the high-drain performance of older Ni-MH batteries. You can find the new hybrid Ni-MHs being sold with names like Hybrio, Eneloop and Rayovac Hybrid.

If, however, being able to recharge batteries quickly is your priority, you may want to look at Rayovac’s IC3 Ni-MH batteries, which have the advantage of being able to be recharged in 15 minutes. (See more information below).

We also review some of the best battery chargers at the end of this article.

Here are some more details on the different battery brands mentioned:

Hybrio Rechargeable Batteries by Uniross

Uniross, a French battery company, recently introduced a “hybrid” Ni-MH battery called the Hybrio. Like disposable alkaline batteries, they come fully charged when you buy them. These batteries are referred to as “ultra-low self-discharging” batteries. Hybrios are said to keep 70% of their charge after a year. You can recharge the Hybrios in any standard Ni-MH charger, and they can be recharged up to 500 times. A pack of four Hybrio cells costs about $12. The AA-sized Hybrios are rated at 2100mAh (mAh stands for milli Amp hour, and indicates battery’s energy storage capacity). Uniross offers a three year limited warranty on these cells. They are also branded as: Ultralast, Again and Again, and Uniross.

Hybrio batteries are available from Amazon

Eneloop Rechargeable Batteries by Sanyo

Eneloop batteries are Ni-MH batteries made by Sanyo in Japan. Like the Hybrios, Eneloops come fully charged out-of-the-box, and have a slow self-discharging range. They can also be recharged in any Ni-MH charger. Sanyo says Eneloops can be recharged up to 1000 times, and they will retain their charged capacity even after 6 or 12 months of storage. (According to Sanyo the specs are: 90% of charged capacity retained after 6 months, and 85% capacity after 12 months at 20 degree Celsius). The AA-sized (R6) batteries are rated at 2000mAh, and the AAA-sized (R03) cells are rated at 800mAh. The price is similar to the Hybrios: a pack of four AA Eneloops costs about $12. The charge times are as follows: AA Eneloops charge in 230 minutes, and AAA Eneloops charge in 135 minutes.

You can get packs of Eneloop batteries from Amazon.

Eneloop batteries are also available with a USB Charger, or a Universal Charger with 8 Eneloop Batteries included.

I-C3 Rechargeable Batteries by Rayovac

In 2004, Rayovac introduced a new line of Ni-MH batteries called I-C3s, that can be recharged in 15 minutes. The I-C3 term stands for “In-Cell Charge Control”, meaning the cells have some circuitry inside them that assists with recharging, allowing for a much quicker charging time. Rayovac says the cells can be recharged “up to a thousand times”. The AA sized batteries are rated at 2000mAh. A four pack of the AA-sized batteries costs about $10. Unfortunately, Rayovac has discontinued these batteries in favor of their own line of hybrid Ni-MH batteries.

I-C3 batteries come with a special charger that features a cooling fan to keep the batteries from getting too hot during the fast charging. There are two charger models: the PS6, which can charge four AA or AAA batteries, and comes with a plug-in 110-120V AC power supply (or optionally, a 12V DC car cord). The PS5 charger model can charge two AA or AAA batteries, and plugs directly into a wall outlet. The PS5 can be used in countries with 220V using an adapter for the outlet.

Ordinary Ni-MH and Ni-CD type batteries can be charged in the I-C3 chargers, but it will act like an overnight charger with these batteries.

Rayovac IC3 Batteries are available from Amazon.

Best Battery Chargers

How about some good battery chargers to go with these batteries?

The chargers featured below are some of the smartest out there — they have built-in protection to prevent overcharging or undercharging. They can also handle most battery sizes.

LaCrosse Technology BC-900 Alpha Battery Charger and Recovery System

The LaCrosse Alpha Charger is a “smart” charger. It has sophisticated monitoring circuitry that controls the charging process, and it is also capable of “renewing” batteries by running full controlled discharge-recharge cycles.

The charger shows battery voltage and charge status on its digital display. It has four separate charge channels so you can charge one, two three or four batteries at a time – even on individual charge programs. This allows you to test one battery while charging the others. It comes with four AA and four AAA batteries, four battery adapters (which convert AA sized battery to C and D sizes) and a carry case. It available from Amazon for about $40.

.

Ansmann Deluxe “Energy 16″ Charger

Ansmann is a German company known for their range of high-end, intelligent battery chargers. Ansmann’s “Energy 16″ charger can handle both NiCad and NiMH (Nickel Metal Hydride) rechargeable batteries. When the batteries are inserted into the charger, they are analysed, and batteries needing reconditioning are automatically restored by several cycles of charging and discharging. The charger will also indicate if a battery has been damaged and cannot be charged.

This charger has ten charging positions: six for AAA, AA, C or D sized cells, and four for 9V cells. The six top positions can handle two AAA or two AA cells or one each of the larger C or D cells.

A LED display shows the state of charging for each cell.

This charger can be used worldwide — it accepts 100-240V 50-60Hz AC.

It’s available from Amazon for around $120.

Ansmann Deluxe “Energy 8″ Charger

Ansmann’s “Energy 8″ charger has all the features of the “Energy 16″ charger, but has 8 charging points instead of 16. It has four AAA/AA/C/D and two 9V positions.

It’s available from Amazon for around $70.

Maha PowerEx “Ultimate Professional” Charger

The Maha’s Ultimate Professional Charger almost lives up to its hyperbolic name. This compact charger can charge any combination of 1 to 8 batteries. You can mix and charge AA, AAA, C and D sized cells at the same time on individual charging circuits. Each battery size also has its own fixed contact charging points (i.e. not a spring). An LCD display shows charging and conditioning status of each rechargeable battery.

Like the Ansmann chargers, Maha’s chargers can restore batteries to their optimal performance level by repeatedly charging and discharging them. It also has intelligent charging technology and overcharge protection. It also comes with an international AC adapter, and short-circuit protection.

It is available from Amazon for around $89.

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Toshiba Dynario Fuel Cell Device Charger (photo: Toshiba)

The first commercially available fuel cell device charger is here! (Well, technically it’s only “here” if you’re reading this in Japan, but that should soon change). Toshiba’s Dynario charger packs fuel cell technology into a portable package that can provide instant power to a dead mobile phone or other gadget, completely off the grid.
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