Take me to your Lithium-Ion AA cells!Credit: Eric Kilby; https://www.flickr.com/photos/ekilby/8223009782/in/photostream/

Now Carbon, now Alkaline, on Cadmium and Lithium! Okay, while not quite the same as a roll-call of Santa's reindeer, a modern Christmas is more likely to evoke visions of batteries than old-fashioned sugarplums that dance through your head.  These days, loading up on power for toys, games and electronic gadgets is nearly as seasonal a tradition as yule logs and eggnog.  Besides the seemingly endless number of sizes needed for all of the high-tech gifts under the tree, nearly every size offers its own myriad of technologies.  But don't shout bah-humbug just yet, because whether it’s a creepy simian bashing cymbals together, a sound and light show hypnotizing babies in their cribs, or a portable razor Saint Nick rides like a sleigh, there’s a type of battery appropriate to every use. 

But first, a few battery facts:

About Sizes
Consumers don't get a say regarding the size a gizmo requires; AAA, AA, D… that’s decided at the factory.  But just who came up with those different letters, anyway, and why? 

An Assortment of BatteriesCredit: W. TurnerFollowing World War 1, as small batteries became much more common the need for a sizing standard developed.  Like Santa Claus answering a kid's Christmas wish, in 1928 the American National Standards Institute (back then known as the American Standards Association) proposed a convention in which the smallest commonly manufactured size was designated “A,” with each incrementally larger size assigned a subsequent letter.  As time went on and ever-smaller cells were developed, the only way to maintain this established alphabetic nomenclature was to use multiples of the already-smallest designation, hence “AA,” “AAA,” and even “AAAA.”  Some sizes have fallen out of popular use, and the original "A" is no longer made.  B batteries are almost non-existent and even the once-ubiquitous "C" size might as well be a lump of coal in a kid's stocking.  Besides some sizes vanishing up the chimney, the intervening decades have seen further incongruities accrue in the convention (such as “N” batteries, which are smaller than “AA”).  Still, the original designations retain their spot in history, if not in order of size or on shelves.

About Brands
Even more numerous than battery types are battery makers. Aficionados may wish to delve into consumer reviews, cutting-edge manufacturing processes and company histories, but last-minute shoppers need be concerned with only one thing: mAh. Milliampere-hours, or  mAh, is an rating of a battery's ability to discharge current over a period of time. The higher the mAh, the longer the battery will last before it's consumed like a night's worth of milk and cookies.

As you'd expect, the physically bigger the battery, the greater the mAh.  "AAA" is a mere elfin tinkerer when compared to the jolly, Santa-sized "D" cell, at least as far as total capacity is concerned.  But even within size categories different makes will advertise varying mAh ratings.  Look for the highest mAh number in the size you need, and buy it.

About Disposal
Some battery types are more environmentally toxic than others, but not even the Grinch would think of throwing old cells in the trash.  Designate a small battery bucket (or box or jar) and keep discharged cells there until your community advetises a hazardous waste round-up.  Alternatively, battery-specific retailers will usually accept "empties."  If you're discarding a 9-volt, tape over the positive and negative terminals to prevent what charge is left from shorting out and causing it to leak.

Single-Life Batteries

Carbon Zinc
Often labeled as "heavy duty," carbon zinc batteries rank as the least-expensive and most widely-available, but are poorly suited to high-drain applications. Low-power, low-drain uses in which carbon zinc batteries excel include things like:

  • Flashlights
  • Garage Door Openers
  • Wall Clocks

Alkaline All Your Batteries Are Belong To UsCredit: davidd; https://www.flickr.com/photos/puuikibeach/4091902754
More expensive than carbon zinc, alkaline batteries are easy to find and the most-recommended battery for general use because of their greater capacity and longer shelf life. While they can be used for the same purposes as carbon zinc batteries, they are most cost-effective in higher-drain devices such as:

  • Electric Shavers
  • Motorized Toys
  • Smoke/Carbon Monoxide Detectors

Non-rechargeable Lithium batteries are superior to both their carbon zinc and alkaline counterparts, with an ultra-long shelf life (up to 15 years!), the lowest voltage drain during use, and the lowest weight of any non-rechargeable battery. They do cost more than the others, but must be considered any time a high-drain, long-lasting battery is desired.  Good candidates for Lithium batteries are things like:

  • Wireless Keyboards
  • Wireless Mice
  • Electric Fly Swatters

Rechargeable Batteries

Nickle-Cadmium (NiCad)
Nickle-Cadmium batteries were the first easily rechargeable consumer batteries introduced market. Frequently found in devices subjected to regular discharge (such as cordless telephone handsets and radio-controlled cars), they've been largely replaced by newer Nickle-Metal Hydride and Lithium-Ion types. NiCads are no longer recommended unless a device specifically calls for them.

Nickle-Metal Hydride (NiMH)
Nickle-Metal Hydride batteries are superior to the older NiCads in every way; think of a turbo-charged Rudolph  lighting the way and then some. NiMHs have four times NiCads' service life, with only a fraction of their dreaded "memory effect."  Their biggest advantage over single-life batteries is their ability to be recharged hundreds of times. They do have lower terminal voltages than non-rechargeables (1.2V versus 1.5V), making them best for applications that aren't voltage-sensitive but which regularly drain batteries down, including:

  • Camera Flash Units
  • Portable Speakers
  • R/C Cars
  • Solar-Powered Lights

Note: NiMH batteries ship in a discharged state, and need to be charged prior to use.

Lithium-Ion (LiON)
Lithium-Ion batteries are NiMH's biggest competitor, and offer several advantages in return for substantially higher purchase price. LiONs have a longer charged shelf life than do NiMHs, a higher "energy density," lighter weight, zero memory effect, and are fully charged right out of the package. Additionally, you'll stay off of Santa's naughty list because disposal of Lithium-Ions is more environmentally friendly than that of NiMHs. A Lithium-Ion battery is a great choice for anything in which a NiMH would be appropriate, but when a longer cycle time between charges is desired.

Christmas Morning

Robot SantaCredit: Andrew Barron; https://www.flickr.com/photos/barronoid/2916269060While you may be tempted to load up toys and contraptions with the batteries you've bought the night before, resist the urge to spoil the best part of Christmas.  Half the fun of giving electronic presents is watching their recipients struggle with inserting all of the batteries; the other half is watching them try to open the blister package they're packaged in!  And, even better, batteries make the perfect stocking stuffer: they don't need to be wrapped, and the wee ones pour out a plethora of power cells, their anticipation of what's to come will grow even more.

Merry Christmas!