One of the greatest boons to the production industry often goes unnoticed and unappreciated: the humble rechargeable battery. In speedlights, wireless microphones, DSLR battery grips, and innumerable other production accessories, rechargeable AA and 9V batteries save money and reduce waste. Being able to “battery up” with fresh cells before every shoot – without worrying about the expense and environmental impact of throwing away partially-used alkaline batteries – also allows for greater confidence and fewer shoots interrupted (or ruined) by battery failures.
The last couple of years have seen substantial advances in technology. Today’s rechargeable batteries can hold their charge for months or years, be recharged 1,000+ times, and provide power comparable to standard alkaline batteries.
Have you ever noticed how a device powered by alkaline batteries will gradually lose power, but the same device with rechargeable batteries seems to be either fully powered or totally dead? That’s because the “discharge curve” of alkaline batteries is very gradual, while NiMh batteries have a discharge curve that stays relatively flat for a long time, and then drops off sharply. This means you can often get more usable life out of a rechargeable battery than an alkaline battery. To be fair, it also means that the battery-life indicator built into many devices doesn’t estimate the remaining life of NiMh batteries very accurately, but since it doesn’t cost you anything to swap out one set of rechargeable batteries for another, it’s a good idea to be proactive about replacing batteries in mission-critical gear like wireless microphones, rather than waiting for the battery-life indicator to drop into the danger zone.
I’ve tried several different brands of rechargeable batteries, with mixed results. Energizer batteries seemed to die after only a handful of charges. Duracells are okay, but don’t seem to last as long as they should. The Eneloop batteries made by Sanyo are quite good, but they’re pricey and sometimes hard to find. I don’t give up that easily though … Just recently, I discovered the Watson family of products, which consists of both specialized replacement batteries for a wide variety of devices, and standard-sized AA and 9V batteries. To my surprise, these Watson rechargeables turned out to be more powerful, more user-friendly, and less expensive than their name-brand competitors.
When I say a battery is “more powerful,” what I’m referring to is the mili-amp-hour rating (mAh). This is the key attribute to look at when comparing batteries. All AA batteries provide electricity at a rate of 1.2 volts, but the mAh rating tell you how long a battery will continue to discharge current at that rate. So, for example, a 2000 mAh battery would power a device that requires 500 mA of electricity for (theoretically) four hours (500 x 4 = 2000). Of course, devices that require more current will deplete the battery faster.
In this case, the Eneloop AA batteries, which sell for $20.19 per 8-pack, are rated for 2000 mAh, while the Watson AA, which sell for $18.50 per 8-pack, are rated for 2300 mAh – 15% more capacity, for about 10% less money. The Eneloop batteries claim to hold a charge longer, and to be able to be recharged more times, which might make them a better choice for emergency kits and flashlights, but the larger capacity of the Watson AAs means a little extra confidence that your wireless mic or camera light won’t die in the middle of a shot.
Eneloop doesn’t make 9V batteries, but Watson does, and they’re also lower-priced and higher-capacity than competitive brands. Alkaline 9V batteries are brutally expensive, so being able to use rechargeables is a big help.
While the Watson 9V charger is – much like other brands’ battery chargers – equipped with a simple red/green LED charge indicator, the Watson AA battery charger is a very slick piece of gear. It sports an LCD screen that gives a four-position charge status indicator for each battery, so that you don’t have to wonder whether it’s working or not. It charges both NiMh and NiCd batteries, which means that it’ll play nicely with virtually any other brand of batteries. It also comes with cables that allow it to be plugged into either a household outlet or a car cigarette lighter, which is convenient for shoots that involve travel or remote locations.
Choosing to stock up on rechargeable batteries is a no-brainer. Deciding which brand of batteries to purchase can be a little more difficult. The big brands offer reliable products, but no value-added features. Watson, the new kid on the block, seems to be trying hard to grow its market share by offering quality products at more favorable prices. I’m definitely going to be buying more of their batteries in future, and it’s good to know that I can use the Watson charger with my older rechargeables as well.