A while back I had the foolish notion that I would like to test some AA batteries to find out what might work best for my Nikon cameras and flashes. My Nikon digital SLR camera with the battery grip and three Nikon Speedlight flashes use twenty AA batteries right out of the starting blocks. Throw a few radio triggers in the bag to sync the flash units to the camera and that adds six AAA batteries and at least one CR2 battery for the transmitter. That is a whole lot of batteries before even considering the fact that you are likely to need that many again as backup units.

It does not take much creative thinking to arrive at the conclusion that you will soon be bankrupted by using disposable batteries in these large quantities. Besides a bunch of camera equipment you probably also have a lot of other battery powered toys at home. Some people say they can’t be bothered with charging a battery before using it and prefer to go the disposable route. Those people keep spending money on batteries every time they wear out a set of old ones. For occasional, intermittent use or long term storage Lithium batteries can be a cost effective choice for disposable batteries but for people like me who use batteries constantly in power gulping devices like electronic flashes the rechargeable option looks much better.

The good news is that you can now buy several brands of batteries that come pre-charged and they can be used straight out of the box. These batteries are often referred to as hybrids because of the way they combine the benefits of disposable and rechargeable batteries into one convenient package. 

One of the stumbling blocks of rechargeable batteries in the past was their characteristic high self-discharge rate. Some people refer to this as “shelf discharge” meaning that the batteries loose power even when they are not in use. The newer hybrid or low self-discharge batteries retain up to eighty percent or more of their charge for six to eight months depending on the brand and the power rating of the battery.

 Rechargeable batteries in general and hybrid or low self-discharge batteries in particular do not put out quite as much voltage as a new disposable battery. Most electronic devices have enough tolerance to permit the lower voltage of the rechargeable batteries but you may run into a few voltage sensitive devices where they will not work properly. 

The catch is that disposable batteries loose power as you use them so they are not always functioning at the full 1.5 volts either. Even though the rechargeable batteries start out at a slightly lower voltage they tend to use the power at a more consistent rate as the battery is discharged. The way a battery consumes power has a lot to do with how you use the batteries, which is one reason why it is difficult to do a head to head comparison between battery types or brands. Testing may only give you an idea of how the batteries perform within the parameters of the testing method and not how it will perform for different uses.

One battery may do well in a device that draws power continuously such as a flashlight that is left on for an extended period of time until the batteries are completely drained. Other batteries are better at delivering large bursts of energy at random intervals in devices like cameras with built in flash units. The problem is that you may use batteries in a way that is completely different from the way they were tested, making the test results slightly misleading. 

After doing a some investigation I came to the realization that I would need to test a lot of batteries in order to gather enough data to be meaningful. Testing four brand A batteries against four brand B batteries is not going to provide much useful information because of the small sample size. One bad battery can skew the test results in such a small sampling. I have also discovered that there is a lot of debate about how a battery should be tested to begin with. There is no simple battery test that will tell you if one brand is significantly better than another but the tests do give some indication of how the batteries perform in general. You can probably use a voltmeter to weed out a bad apple in a bushel of batteries but actual battery testing is a bit more complicated because you have to devise a test that shows how the battery will perform in actual use.

There are a couple of very good “smart” battery chargers out there (a whole subject in itself) and I was ready to rush out and buy one so I could get a handle on what my batteries were doing. Then I found out that the charger I was planning to buy seemed to have developed the habit of going haywire, overcharging batteries and melting the plastic battery charger housing. Another brand of charger I looked at required about forty keystrokes to program in the functions to charge and test the batteries. No thanks. 

There are two basic types of battery chargers; slow chargers (it’s hard to make a bad slow charger) and fast chargers that tend to fry your batteries and kill them prematurely. The more complex smart chargers can do things like recondition your batteries by going through several charge and discharge cycles, which sounds like obedience training for batteries. That process can take quite a long time, maybe a couple of days but may be able to restore function to some batteries. A good battery charger will charge the batteries on separate channels or circuits so that one bad battery does not affect the whole lot. 

There are many sources for battery tests including the battery manufacturer’s websites which can teach you a lot about batteries (and marketing). You might also want to check out user reviews on retail sites like http://www.amazon.com it’s not a perfect way to make a decision but it may be helpful (or a minor relief) to know you are not the only one contemplating a particular brand of battery to sink your hard earned cash into. User reviews are what made me rethink my battery charger decision, at least for the moment.

I have quite a few Energizer AA batteries and chargers that I have been using for about a year now. They had a sale on the chargers with batteries at my local grocery store that came along at just the right time when I needed to buy a bunch of batteries. I bought two sets and then bought another and another each time I went back to the store to buy groceries. Of course I’m a defect magnet so I ended up taking back one charger and set of batteries, which was not that big of a deal since I have to eat all the time and I go to the grocery store just about every week. Since I started using the  

So far I’ve only had one defective battery problem while I was out working and that was while I was out of town and of course it was the one time that I did not bring along any spares. That meant I could not use my battery grip but I still got to lug it and eight batteries around all day. With the Energizers, I can buy replacements in just about any city in the US so it’s not a deal breaker. I got by without using the battery grip that day and kept on working.

So for me the first round was won (by default) based on price, availability and dumb luck. Now I am looking into batteries which can hold their charge for days, weeks or months before being used. A lot of people have put a great amount of time and effort into testing various brands and types of batteries so the challenge is not to replicate that work but to use it to determine which batteries will perform best for the applications I have in mind. As I stated earlier, how you use and maintain your batteries has a lot to do with how well they perform. 

There is a very good battery comparison at http://candlepowerforums.com/vb/showthread.php?t=79302 where you can compare the discharge rates of many different batteries. My Energizer 2500 batteries made the top ten when the list was last updated. 

There is also a pretty good discussion of low self discharge batteries at http://forums.dpreview.com/forums/readflat.asp?forum=1023&thread=26078814 

An interesting result of all this testing is that the performance of the low self-discharge batteries seems pretty consistent between the top brands. What this means in practical terms is that you can choose the lowest cost battery option that is readily available where you live and by purchasing the batteries locally you can always pick up spares as needed. I was able to offset some of the cost of my initial rechargeable battery purchase by surfing local sales and using discount coupons.

Normal rechargeable batteries usually have higher total capacity than the low self-discharge type so if you can remember to charge them the day before you are going to use them that is not a bad way to go either. I’m interested in the low self-discharge batteries for camping trips, travel and other applications where I may not use the batteries for a couple of weeks and do not have convenient access to electric power to recharge batteries along the way. 

Here is an interesting test between the Sanyo Eneloops vs the PowerEx Imedion batteries using a Nikon flash to simulate real world stress conditions. http://www.photomalaysia.com/forums/showthread.php?t=74823

The Imedion manages to take the most shots because of its higher power rating but the Eneloop seems to recycle the flash faster for a fewer number of total shots. Recycle rates mean everything to photographers so the Eneloops would seem to be the preferred choice for fast action flash photography.

So it’s not just about which battery has the most power but also how the power is delivered in real world situations.

You may also find out that rechargeable batteries are larger in diameter than some disposable batteries so you should check to see if they will fit correctly in all your devices. I can’t get the Energizer batteries to go in my Mini Mag Light flashlights but alkaline or lithium cells may be a better choice for those because they are not in use all the time and sit in a drawer for months at a time.

I ran across a lot of good resources and information on the internet that are worth sharing so here are a few in no particular order.

http://www.calrecycle.ca.gov/ReduceWaste/power/rechbattinfo.htm This is a very good eco-friendly site put out by the state of California with loads of great information on batteries. Watch out, they may convince you that you don’t even need batteries.

http://en.wikipedia.org/wiki/Low_self-discharge_NiMH_battery A short article on the basics of how a low self-discharge battery works.

http://climber.org/gear/batteries.html Battery wisdom from on high! Several mountaineers tell you everything they have learned the hard way about using batteries in cold and demanding environments. 

http://www.rechargeable-battery-review.com/ All about rechargeable batteries and battery reviews. Do You Use or Are You Planning To Buy Rechargeable Batteries?

http://michaelbluejay.com/batteries/ A good battery guide and comparison. If you have no idea what to choose this guy will tell you. It’s a good plain talking guide about the good, the bad and the ugly battery.

One of the most consistently recommended sources for purchasing batteries and chargers online is Thomas Distributing. http://www.thomasdistributing.com/ 

For some of the world’s most powerful low self-discharge batteries you will ever see… as in, “Do you feel lucky punk?” go to http://www.horizonbattery.com  where you can buy the Ansmann Max E 2500 mah AA batteries directly from the manufacturer.

I like also to use Amazon.com for the service, convenience and customer reviews. http://www.amazon.com/ 

You can use the Amazon.com link on my blog http://www.insidetheviewfinder.com/