It occurred to me that in recent posts I’ve talked about what kind of rechargeable batteries to use, how to charge them, and how to store them, but I haven’t actually talked very much about WHY you should use them. I’ll do that now!

This might be obvious to some of you, but for others it’s a pretty hard sell when they see price tags of $10-20 for a set of 4 AA or AAA NiMH rechargeable batteries (I prefer Sanyo Eneloop batteries) when you can buy a huge box of alkaline batteries for less (here’s a box of 48 AA’s for only 6).

Here are 3 reasons why you should use rechargeable batteries in all your electronic gadgets and camera equipment, especially in your Speedlite flashes:

1. Better for the Environment: Millions and millions of batteries get disposed of every year and most of them go into landfills. They all contain heavy metals and they really aren’t very good for the environment. Even when recycled they take lots of additional energy to reprocess, which is simply wasteful when their are excellent rechargeable alternatives available.
2. Cheaper in the Long Run: although alkaline batteries are relatively cheap to purchase, you can reuse your rechargeable batteries hundreds of times and they quickly pay for themselves. For the full time pro or the advanced amateur this is probably a no-brainer. But it’s still true even for a beginning photographer. If you use a Speedlight Flash that takes 4 AA batteries, I’m willing to bet that you have to replace your alkaline batteries at least once a month, and maybe even more often if you use it a lot (even spectators at a wedding often can’t make it through an entire event on one set of batteries). So even if you only replace your batteries 12 times per year, a set of 4 Eneloops for $13 is already cheaper than that big box of alkalines for $16, and you can save even more by buying the rechargeables in bulk packs. If you are using 2 or 3 flashes plus a few other electronic gadgets that use AA batteries these savings multiply (and you can share your spare batteries amongst all the devices!).
3. Better Performance: I find that NiMH batteries recycle my flashes faster and last longer than alkaline batteries. This is counter-intuitive since rechargeables are typically only 1.2v vs. 1.5v for alkalines, but they are different technology and it really is true. You may find that alkaline batteries work better than NiMH’s when they are both fresh, but that alkalines drop off very quickly. I find that NiMH’s continue to perform very well until they simply stop working; alkalines work well initially but then performance quickly drops off to the point where it might take 10 seconds to recycle a flash (compared to 3-4 initially). This was honestly the main reason that I switched in the first place, but in retrospect the other reasons are just as important.

Note – if you haven’t read it yet, you really owe it to yourself to read my earlier article about Better Rechargeable Batteries before you actually buy any NiMH batteries. They are not all created equally…

I get questions all the time from people using NiMH Rechargeable Batteries that don’t last very long or that don’t seem to put out full power. The obvious question is whether there is something is wrong with the batteries, the charger, or both. These batteries are pretty expensive and it can be really annoying when they don’t do the job they are needed for.

Unfortunately, rechargeable batteries continually lose some of their power in a process called self-discharge. This process occurs at different rates in every type of battery, and it occurs very quickly in standard NiMH batteries. In my experience they only hold enough charge for a few days before the reduced charge levels becomes obvious. When I try to use them in my Speedlite flashes I find that I really have to charge them the same day, or maybe the night before, if i want to get decent life out of them.

If you need your batteries to last longer then you need to get low self-discharge batteries (often marketed as Pre-Charged batteries), such as Sanyo Eneloops. I find that these batteries, even at only 2000 mAh, last far longer and are much more useful than any of my 2500 – 2900 mAh standard NiMH batteries. I now have enough of these batteries for use in all of my flashes plus a spare set for each flash as well. You can leave these in your camera bag for months and they only lose a small percentage of their power.

For more information and to learn about other brands of batteries, check out the Low Self Discharge NiMH Battery article over at Wikipedia.