As Video Packages Shrink, Dependence on Small Batteries Grows

The cost of these individual cells can add up fast — especially if the user is purchasing high-end professional batteries at retail for a one-day video shoot. Now, with so many small batteries needed by a diverse range of devices, it would perhaps be wise to consider different options for powering such devices.

Often, battery usage patterns come from old habits. Some video crews who have long used batteries purchase only top-quality cells — like Duracell Procells or Energizer Lithiums — and toss them after each day of shooting in order to start fresh on another day. These crews just build the batteries into the cost of the job.

Other more cost conscious crews purchase the cheapest batteries they can find and throw them away when they die. Still others use rechargeable cells and try to milk battery life to the maximum — marking and organizing each cell for recharging at the end of the shoot day.

Of all the batteries used in professional video and audio today, AA size cells are the most popular. In 2011, single use AA cells accounted for about 60 percent of all alkaline battery sales in the United States and 58 percent in Japan. 

Nine-volt batteries are also popular with some professional gear, especially audio mixers and older wireless microphones. However, the market for lithium-ion batteries is now increasing. According to Frost & Sullivan, a growth-consulting firm, the global market of rechargeable lithium-ion batteries is projected to be worth $23.4 billion in 2016.

BitBox, a designer and manufacturer of battery-operated electronic equipment in the United Kingdom, did an extensive comparison test of the world’s most common single-use battery brands. The company tested batteries using constant current discharge for both low and high-drain devices. Low-drain devices include items such as small electronics, while high-drain devices include digital SLR cameras. 

The majority of batteries are rated in milliamp-hours, or mAh, BitBox noted. “1000 mAh represents the equivalent energy load of 1000 milliamps applied for one hour,” the battery testers wrote. “However, the issue with mAh is it fails to account for falling battery voltage. In general, a digital camera will use a switching converter, which will get more life with a higher mWh battery. But a torch, toy or similar device is fairly independent of voltage, and will last longer with a higher mAh battery.”

This same issue applies to professional video gear. Battery life is often different depending on the type and individual design of each device. Some experimentation is required to get the best battery life from each component in a chain of devices.

For low-drain devices, BitBox discovered, discount brand batteries performed very well. In fact, Ikea’s alkaline won the test as best overall. The Kirkland Signature battery from Costco was the best “supermarket” brand battery tested in the 200mA test and in the 1000mA test. It appears to be a re-labeled Duracell. 

Interestingly, Duracell standard batteries sold at retail in twin packs were found to perform less effectively than some discount brands, while Duracell’s own “Simply” discount brand cells (sold in many countries) performed similarly to standard Duracells.

Duracell’s Procell and Energizer Industrial batteries used by many professionals were found to be good for the price if the user is willing to buy them online in larger quantities.

The Energizer Ultimate Lithium and Varta Professional Lithium cells also performed very well, the tests found, achieving about 3000 mAh each with the Energizer beating the Varta cell at all cut-off voltages. These batteries would be a good choice in an application which needs to last a very long time and where changing batteries is difficult or inconvenient.

However, BitBox said, these high-end cells provide poor value for the money as they cost nearly seven times as much as the discount store alkaline cells, while providing only a 60 percent increase in total measured capacity.

Zinc cells, the lowest cost batteries of all, have poor performance and should be avoided for professional use. Even in low-drain applications, alkaline cells will perform better, the tests confirmed.

Varta’s High Energy Alkaline was the best performing alkaline cell in high-drain tests and had very long life. However, it provided only marginally more lifetime than the Energizer Industrial cell for twice the price. In the high-drain tests, the Ikea alkaline won out again as the best battery. The Duracell Procell also did very well.

For those who prefer rechargeable batteries, the choice becomes easier and less confusing. Panasonic's Eneloop cells, which were developed by Sanyo before being purchased by Panasonic, have earned a reputation for quality since being introduced in 2005.

The Eneloop, available in AA, AAA, C and D types, is a low self-discharge NiMH battery. That means it loses its charge more slowly than ordinary NiMH batteries. The rate is ten percent in the first year, as compared to about four percent of the charge per day for other designs of NiMH batteries. 

Eneloop cells are sold pre-charged and can be used immediately out of the box. Standard NiMH batteries lose their charge so quickly that immediate use isn’t feasible. Due to the number of alkaline batteries that Eneloops can replace during their lifecycle, the Eneloop product line is marketed as being as environmentally friendly.

Professional video users should consider Eneloop Pro, a second generation battery introduced in 2013 which has a 2550 mAh nominal, 2450 mAh minimum capacity. It’s discharge rate holds 85 percent of energy up to one year. No Eneloop batteries are available in nine-volt cells.

Just as with video technology, battery technology is moving fast and battery chemistries are improving. For example, researchers at Nanyang Technology University in Singapore have developed new ultra-fast-charging lithium-ion AA batteries that can be recharged up to 70 percent in two minutes. The batteries have a life span of more than 20 years and 10,000 recharge cycles — rather than today’s typical 500 recharge cycles.

With the new battery, not yet on the market, the traditional graphite used for the anode (negative pole) in lithium-ion batteries is replaced with a new gel material made from titanium dioxide, an abundant, cheap and safe material found in soil. It is commonly used as a food additive or in sunscreen lotions to absorb ultraviolet rays.

Manufacturing this new nanotube gel is simple. Titanium dioxide and sodium hydroxide are mixed together and stirred under a certain temperature so battery manufacturers will find it easy to integrate the new gel into their current production processes. With licensing deals now in the works, the university predicts the technology could be on the market within two years.

Even quicker to market will be a new battery innovation called Batteriser, a very thin .1mm reusable steel clip that’s said to increase the life of AA batteries by up to eight times when used with voltage sensitive equipment. It goes on sale for $10 in September with clips for four AA cells.

Bob Roohparvar, the inventor, said Batteriser brings intelligent voltage management to any AA battery, regardless of chemistry. The steel clip is attached to the cell. It adds no bulk and the battery still fits easily into any battery compartment.

With Batteriser, users can tap into the energy remaining in batteries once their voltage has fallen below 1.35 volts, which is the cutoff point of many battery-operated electronic devices. Roohparvar estimates that as much as 80 percent of a battery’s power potential is left after it is considered “dead” by the device and that residual energy can be revived with the Batteriser clips.

The Batteriser, he said, has circuitry that will boost cells with as low as 0.6 volts and will maintain the voltage at 1.5 volts. However, Roohparvar warned, it won’t help with every product. For example, many LED light designs work on a constant current that does not cut off when a voltage point is reached. For such devices, Batteriser won’t help.

However, for devices like audio mixers and other electronics, the Batteriser kicks in when the voltage in the battery has decreased below the device’s cut off limit. Roohparvar suggested the Batteriser should be tested with each device to determine its effectiveness.

For video professionals who count on the reliability of AA batteries, Roohparvar said there’s a good reason to spend more money for better quality batteries.

“The difference between the top brands of batteries is negligible,” he said. “However, if you go to a really cheap battery, the resistance is very high. Your battery will stop working sooner because its goes below 1.3 volts and the device being powered shows it’s no longer working. The better brands have resisters that that keep the cell closer to the nominal open voltage circuit.”

At the end of the day, Roohparvar said, battery technology today is far too wasteful. “What we are trying to do is extract and harness the energy out of all batteries so they don’t end up in landfills,” he said.

“Right now, only two percent of people recycle batteries. The energy to produce batteries each year is the equivalent of lighting up a city like Las Vegas for 75 years. You have to manufacture and transport the batteries, and the numbers are mind-boggling. It is very wasteful process.”