Hearing aids and battery life

When it comes to selecting a hearing aid, it can be quite overwhelming. Which manufacturer? What level of technology? What style? Made for iPhone/ASHA Bluetooth streaming or Bluetooth Classic? It’s your audiologist’s job to guide you through this process, talk you through the options, and recommend an option or two that will suit YOU the best.

One other option to choose from in modern hearing aid technology is battery type - cell battery or lithium-ion rechargeable?

Does it make much of a difference in which one you opt for?

Firstly, let’s look at the cell battery.

Hearing aids that use cell batteries mean that you need to replace the battery on a regular basis. You also need to open the battery door of the hearing aid when not in use to conserve battery life. Also important to note is that hearing aid cell batteries are zinc-air batteries. They come with a sticker on them which needs to be peeled off prior to use. Once this sticker is removed, the zinc and oxygen reaction activates the battery and it begins to discharge whether you use the battery or not.

Zinc-air batteries come in 4 sizes: 10, 312, 13, and 675. The bigger the battery, the longer it lasts (and the bigger the hearing needs to be to accommodate it). 675 batteries are only used in behind-the-ear hearing aids for those with severe to profound hearing losses. Size 10 batteries are typically used for the smaller in-canal hearing aids (invisible-in-canal and completely-in-canal), as well as the odd receiver-in-canal hearing aid (although this is less common in current technology due to Bluetooth connectivity requiring more power than these can provide). The most common battery size is 312, although 13 is more popular than it once was due to most hearing aids offering direct Bluetooth streaming these days, and this has a significant impact on battery life.

The life expectancy of cell batteries in hearing aids is:

*Depending on Bluetooth use; these figures are based on p to 5 hours of Bluetooth streaming/day

** This can vary, depending on the brand of battery

Lithium-ion rechargeable batteries, on the other hand, are designed to last all day and require charging every night (just like a Smartphone). With moderate Bluetooth streaming (up to 5 hours a day), you can still expect a comfortable day’s battery life. Lithium-ion batteries are expected to last 4-6 years (this can be shorter with heavy Bluetooth streaming). The battery capacity is expected to be around 80% by the 3-year mark, and should still comfortably last a full day’s wear. There is no need to open the battery door to turn it off overnight. Simply placing the hearing aid in the charger turns it off, and it should automatically turn on when removed from charging, so this can be a good solution for those with dexterity issues. The cons - if you’re forgotten to charge your hearing aid, there is no option to alternate with a cell battery; the hearing aid must be charged to work. Luckily, lithium-ion batteries charge relatively quickly - it would typically take 3-4 hours for a completely drained lithium-ion battery to fully charge. If you need a top-up on battery life during the day, 15 minutes in the charger will usually give you an extra 3-4 hours of battery life.

What factors affect battery life?

Without a doubt, hearing aids in 2021 work much harder than they used to. Faster processing chips, noise reduction, binaural processing/streaming features, Bluetooth use, accessory use, and CROS/BiCROS fittings can all impact battery life. So if you’ve been doing more Bluetooth streaming than usual, or in more challenging/complex noise environments than usual, expect the battery to drain faster than usual. Be aware that some manufacturers have better battery life in their hearing aids than others as well. People who have worn hearing aids for a long time may be more used to their 312 or 13 batteries lasting 7 or 14 days respectively; however, the hearing aids from 5-6 years ago simply weren’t required to work as hard.

Rechargeable hearing aids offer a solution that is more environmentally friendly, easier to manage for those with dexterity concerns, safer to use around young children (no loose cell batteries floating around), and provides peace of mind that you can get a solid day’s battery life (even if you stream via Bluetooth for up to 5 hours a day).

Cell battery hearing aids, on the other hand, provide peace of mind for those who are unsure of rechargeable batteries or prefer to simply change the battery whenever it runs out.

Here is a rough guideline on the expected battery life from some of the main hearing aid manufacturers:

*Expected daily battery life when lithium-ion battery is new

** Depending on amount of Bluetooth streaming

The list above is by no means exhaustive but gives an idea of how different manufacturers’ hearing aids processing affects battery life. For those that intend to use a lot of Bluetooth, battery type should definitely be a consideration when looking at purchasing hearing aids. However, other factors, such as lifestyle, hearing loss and type, ear canal size, dexterity, and more, will impact your audiologist’s recommendation to you. Going to an independent clinic also means that you will have more options available to you so that you can truly find the solution that suits you the best.