AA Batteries & Chargers
AA batteries can be one of the most annoying aspects of digital photography. So many devices take AA batteries, and there are SOOOO many different types of batteries out there! Which should you buy / use? More importantly, which charger should you get?
I'll cut right to the chase: This discussion mostly covers e great debate is always this- Should you use AA batteriesIt's currently the spring of 2010, and here's the situation with the current technology in AA batteries:
Alkaline Disposable Batteries
Alkaline batteries are like the McDonalds of the battery world. You can buy them anywhere in the world. Bring that AA battery tray for your vertical grip when you go on that trip where electricity might be scarce... However in general, it's not very conservation-minded to be using "disposable" AA batteries on a day-to-day basis, such as in a camera flash, and throwing them away at the rate of dozens per month. You don't ned to be a tree-hugger to understand that batteries in a landfill can't be a good thing. So, that's why we have recharge-ables. More on that later. Anyways, in a camera flash, Alkaline AA's are a last resort. Pretty much any brand will do, but of course Energizer / Duracell are going to be the most reliable.
Lithium Disposable Batteries
Lithium AA's are incredibly expensive, but they pack a lot of punch. In a hotshoe flash they recycle VERY fast, and then they die hard once they run out of juice. Just like alkaline "disposable" AA batteries, you can buy a set and throw them in the bottom of your camera bag for that emergency situation. Even if they sit there for 6-12+ months, they'll still work perfectly. Energizer Lithiums are the most common.
NiCad Rechargable Batteries
NiCad batteries are oldschool. Don't buy 'em. Unless I'm totally missing something, in which case please let me know. ;-)
NiMH Rechargable Batteries
NiMH batteries have FAR fewer flaws compared to NiCad's. They live longer, they hold a charge better, and are pretty high capacity. There are plenty of great quality NiMH's out there, personally I have Calumets, but here's a quick list of the ones you should be able to trust: Energizer, Duracell, Ansmann, Maha Powerex, Lenmar, Calumet, Delkin, ...did I miss any? Currently, a decent capacity for a NiMH battery is about 2500 mAh, but I've seen up to 2900 mAh from some brands! Expect to pay about $10 per 4 batteries. Personally, I'd buy a pack of 12, 16, or more... :-)
However, standard NiMH batteries still suffer from one flaw- They lose their charge pretty rapidly after you take them out of their charger. They don't go "bad", in fact, they can live healthily for years and years. They just start to lose their charge, as if they're being used. But, read on...
Hybrid NiMH Rechargable Batteries
In the past few years, a few companies have developed new technology known as "hybrid" NiMH batteries. They aren't usually as high-capacity as standard NiMH's, (maybe 25% less capacity, usually around 2000 mAh) ...however they hardly lose ANY charge over time, and some are rated to go 6 months with 90-95% of their full charge! The popular brands are the Sanyo Eneloop and Ultralast Hybrio's. Expect to pay about $10-$12 per 4 batteries.
NiZn Re-chargable Batteries
Oh, I forgot one *OTHER* minor drawback with NiMH batteries: their maximum voltage. Most are 1.2 volts (compared to Alkaline and Lithium AA batteries, which are 1.5 volts..) A lower voltage means they'll perform SLOWER, they'll take longer to re-charge. To put it simply. ;-) Anyways, that brings me to the latest development, which is the "NiZn" AA battery by a company called PowerGenix. They're rated at 1.6 volts, and can be clocked at 1.85 volts even. Basically, a turbo-charged AA battery. It's not gonna get very good MPG, and it's going to risk overheating. But more on that later...
...So, if we were to end this discussion now, the bottom line would be: NiMH re-charghables are the way to go, if you can live with the medium-fast recycle time. Either buy the normal NiMH's and keep them in a high-tech charger that has a non-damaging "trickle-charge", ...or get some Eneloop hybrid batteries that you can charge, put back in your camera bag, and trust them to be fully charged whenever you need them, even if your next photo shoot / job isn't for a few weeks. OF COURSE, if you're super geeky, there is still a lot to be discussed. ;-) Read on!
mAh (Miliamp-Hours)
mAh is the number that tells you the total amount of electricity a battery can hold. The number of pictures you can take, the number of flashes you can "pop", or, simply, the number of hours that you could light a flashlight.
Most AA batteries are around 2000-2500 mAh these days. Depending on the flash power, four AA batteries in a flash this might get you 100-200 or even 300 flash images before needing to be re-charged.
Volts
Volts = how much power a battery can give off *AT ONCE* Like the size of the "pipe" delivering the electricity- If you've got a lotta volts, you could empty the entire capacity of a battery very quickly. Therefore, Volts kinda dictates the *speed* that your flash can operate at. You can have all the mAh you want, and the flash will last for hundreds of pictures, but if the battery doesn't have that many volts, it's going to take it's sweet time between each flash "pop"...
Actually though, most hotshoe flashes aren't built to take that much power anyways . The bulbs are not actively cooled like in a studio strobe, (you can hear a little fan going when you turn on an Alien Bee) ...so it's really quite risky to use one of those high-powered battery packs from Quantum, or one of the newer, high-voltage NiZm AA batteries like from PowerGenix.
Most AA batteries are 1.2 or 1.5 Volts. The NiZm batteries have been rated at 1.6 Volts, and have been "clocked" to actually be capable of 1.85 Volts! HERE is a strobist blog entry on these batteries, with a Youtube video showing just how fast you can overheat your flash by using them. RISKY!
Recycle Time
Recycle time is how long it takes the flash to recharge and get ready to fire again. At full power, most hotshoe flashes take quite a few seconds to recharge. (10+ seconds) At lower powers, they recharge almost instantly and you can shoot pretty rapidly for the first 5-10 shots. Then the batteries start to slow down a bit. It is usually best to let batteries rest every few minutes, and it's even BETTER to let the flash bulb rest. ;-) We already talked about Volts and mentioned how it affects the recycle time. The more volts your system can operate at, the faster it can recycle. If you want to read an incredible test on AA battery recycle times, click here. It was performed by a forumer named Mithrandir on an Olympus community forum. Bottom line: The Lithium AA batteries are the fastest by a hair, followed very closely by the quality NiMH batteries. The hybrid rechargeables and the other generic rechargheables are next, taking a few seconds longer to recylce, and the Alkaline AA's take forever to recycle, right off the bat. (NiZm batteries were not tested, I suspect they'd be even faster. But as mentioned, NiZm batteries approach the realm of jeopardizing your flash bulb. Your call!)
Bottom line- Usually it's good to have more .
Final verdict in this respect: - Buy a *quality* set of NiMH batteries, and maybe a set of Lithium batteries to throw in your bag and leave for emergencies. Fortunately Lithium batteries are very lightweight, and won't slowly lose their charge if you leave them in your bag for 6 months. They'll be ready to rock at any moment when that one last-minute photo shoot comes along and all your rechargeable AA's are all dead.
Chargers
Let's see if we can't make this 10x more complicated, haha... There are an equal number of chargers out there, and even worse opportunities to be let down
