AO/Beck: Hi Tom. Thanks for your time this evening.
Begley: Hi Doug, thanks for the invitation.
AO/Beck: Let's start by finding out a little about you, if you don't mind.
Begley: I received my BA degree in History form the University of Colorado. After graduation, I spent two years as an Air Force Intelligence Officer developing bombing charts for the military. After leaving the USAF in 1971, I joined Campbell Soup Company. I have spent my career with consumer package goods companies. I joined Rayovac 10 years ago as their Director of Hearing Aid battery Sales.
AO/Beck: That's a diverse history. You don't meet many folks who've mapped out bombing runs! Sounds like you've had an interesting career. Let's switch gears and learn a little about batteries. Certainly the four big sizes have to be 10, 13, 312 and 675. What the heck ever happened to size 5?
Begley: Well, size 5 is still there. Rayovac developed it at the request of the hearing aid industry. Manufacturers felt that audiologists were losing potential customers because some individual's ear canals were too small to be fit with a CIC using a size 10 battery. Rayovac invested the time and resources over the next year and introduced the size 5. Hearing Aid manufacturers have over time become much more efficient in their space utilization. Now they are able to use a size 10 for all but the smallest ear canals. That provides the wearer with the most battery life along with the smallest hearing device.
Rayovac will continue to invest in new product development to fill future needs. That's part of R&D in today's world. Back in 1986, when we developed the size 10 battery, there was little market for it. Size 10 did not become popular until CICs started to thrive. Interestingly, the size 10 is the fastest growing of all hearing aid batteries at this time.
AO/Beck: Tom, what are the most popular battery sizes, and what are their approximate market shares?
Begley: Sizes 13 and 312 are tied for first place; they each have 33 percent of the market. Size 10 represents 27 percent, and size 675 is about 10 percent, size 5 is less than 1 percent.
AO/Beck: What about the types of batteries out there? Are mercury and silver still available?
Begley: They can be found, but they are rare. In essence, the whole market is zinc-air. The original hearing aid batteries were mercury. They were terrific because they could power high-powered instruments. But, when zinc-air came out - it lasted twice as long as mercury and cost less than half as much. Zinc Air also was more environmentally friendly than mercury. Mercury and silver remained available because they could power the most powerful devices on the market. Because of the introduction of the high power batteries there was no longer a widespread need for mercury & silver batteries and they are no longer sold. In the case of mercury it was banned from sale due to environmental concerns. While silver is still available its high cost has led to it no longer being stocked by most professionals.
AO/Beck: What is the duration of battery life, if we were to define it from the date of production, to the date at which the patient peeling off the tab gets full battery life? In other words, what is the sitting shelf life?
Begley: Rayovac and most other manufacturers offer a three-year shelf life. Of course that will vary with changes in temperature and humidity, and other factors, but if well maintained, three years should be expected. We have found that batteries lose about 5 percent of their capacity per year. So after three years, the well-maintained battery has 85 percent of its capacity. By the same token, we have seen batteries that have been found in the back of a drawer, or forgotten somewhere else, and even after 14 years have worked just fine.
AO/Beck: That's pretty amazing. How long has zinc-air technology been around?
Begley: Zinc Air Technology has been around for about 90 years. Button Cells as we know them were introduced in the 1940s. Zinc Air became the battery of choice for hearing devices in the late 1980' s
AO/Beck: Tom, what about the patients who want to store the batteries in their fridge?
Begley: Absolutely not. That's a big mistake. If the zinc-air battery is placed in the fridge, the batteries will absorb moisture through the air holes under the battery tab. As the moisture is absorbed through the air holes the battery will be filled up with the moisture, discharge, and the wearer will see reduced battery life. So batteries should definitely not be stored in the fridge.
AO/Beck: What can you tell me about storing the batteries in the dry aid kit? In other words, if the hearing aid is stored in the dry aid kit, and if the battery door is open, should the battery stay in the open battery door, or should the battery be stored outside of the dry aid kit?
Begley: Maximum battery life is based on relative humidity equilibrium. So in essence, it shouldn't be too moist or too dry. If you have a really effective dry aid kit, it will dry out the battery and result in reduced battery life. So in essence, the best course of action is to remove the battery from the hearing aid, and just place the hearing aid, without the battery in the dry aid kit.
AO/Beck: Tom, what are some of the mistakes people make regarding batteries?
Begley: People tend to think that a battery tester will tell them how long the battery is going to last. It doesn't work that way. The discharge curve of an alkaline battery is very steep. If you were to measure it over time, you could probably predict pretty accurately when it was going to expire. However, zinc-air batteries have a very flat discharge curve. Zinc-air will work for a long time and then expire suddenly. So, other than knowing how long previous batteries have lasted in the specific application, the expiration date cannot really be anticipated using a battery tester. Of course a battery tester is good to tell you yes or no, the battery is good or bad. Another common mistake is when consumers test their battery and notice that it does not test 1.4 volts. 1.4 volts is a zinc air batteries nominal voltage. However, the battery's operating voltage is a little less than that. So what sometimes happens is that the user will take a very accurate voltmeter, or another measuring device, and observe that the voltage is less than 1.4 volts, and they'll conclude that the battery isn't good. That is an incorrect conclusion. The battery is fine as long as it maintains the operating voltage of around 1.1 volts, not the nominal voltage.
AO/Beck: I think we all have patients like that! Typically it's a patient who refuses to use the word Hertz. They insist on saying, cycles per second, and they are, or they were at one time, some sort of an engineer. But then again, if we were all the same, it would be boring!
Begley: We actually have a letter that one of our engineers wrote some ten years ago regarding nominal voltage vs. operating voltage that we send out a few times a month to audiologists and consumers who have called us with questions about voltages and they get confused by there issues.
AO/Beck: Another issue I would like you to address is size and power. Where are we going?
Begley: With the size 5 we have probably reduced the size of the battery to as small as is possible. When Rayovac introduced the size 10 in 1986 there was a very small market for that size. With the introduction of the CIC the size 10 became the fastest growing size. The size 5 growth is dependent on the device manufacturers developing a breakthrough instrument for the size 5 like they did using the size 10. Power is the next battery breakthrough. Battery manufacturers are researching how to increase the power and the capacity of the battery in order to satisfy the needs of the manufacturers and the wearers. Increased capacity and power will be available soon, and will be used by the hearing aid industry as quickly as we can produce them. In 1985, when the size 10 was introduced, it had 55 milliamp hours. Today, the new size 10 product has 90 milliamp hours. This has been accomplished with no change to the outer dimensions of the cell. That's amazing progress.
AO/Beck: I agree, it really is an amazing product. Of course no matter how long it lasts, the patients have a tendency to say, Is that all?
Begley: You're right - we tend to lose track of how quickly we're progressed with this technology.
AO/Beck: What do the numbers mean.... 13, 312, 675 and 10?
Begley: I don't know where 13 and 312 and 675 designations came from. But the story goes that the size 10 was named a ten because of the movie with the same name. The size 10 was thought to be the perfect battery, and Rayovac's marketing manager at the time called it a 10. When the size 5 was introduced it was half the size of the 10 - we decided to call it a size 5.
AO/Beck: Thanks Tom. One last issue before I let you run. Can you tell me how large the battery marketplace is, and what percentage of that does Rayovac capture?
Begley: The total worldwide sales are about 400 million hearing aid batteries per year. Rayovac has about 60 percent of the total.
AO/Beck: Thanks Tom, I learned a lot and I appreciate your time and knowledge.
Begley: Thank you too Doug, it's been a pleasure.
Healthy Hearing (www.healthyhearing.com) is grateful to the author and Audiology Online for allowing us to republish this material on Healthy Hearing.
AO/Beck: Hi Tom. Thanks for your time this evening.