Non-Rechargeable vs. Rechargeable Hearing Aid Batteries: Size 10, 312, 13, 675 Hearing Aid Batteries
Non-Rechargeable (disposable) zinc-air batteries have been standard hearing aid batteries for a long time. They have replaced older mercury-oxide batteries and after introducing mercury-free zinc-air batteries, they have become de facto standard for hearing aid batteries.
However, rechargeable batteries are being used more and more in everyday electronics and as such, they are slowly entering the hearing aid market as well. But, there are several very important issues that rechargeable batteries face when being used as hearing aid batteries...
Hearing Aid Battery Sizes
Hearing aid batteries are button cell type of batteries and they come in several standard sizes, shown in the following table:
|Common Battery Name||Tab Color||Dimensions||Zinc Air Capacity||Alkaline Capacity||Silver Oxide Capacity||NiMH Capacity||Silver Zinc Capacity||Amazon Link|
|10, Yellow tab, PR70, 7005ZD, AC10, DA10, ZA10, AC10/230, DA230||Yellow||5.8 x 3.6 mm||90 mAh||-||-||11-15 mAh||15-18 mAh||Size 10 Hearing Aid Battery|
|312, Brown tab, PR41, 7002ZD, ZA312, p312||Brown||7.9 x 3.6 mm||160 mAh||27-33 mAh||40-45 mAh||20-25 mAh||30-32 mAh||Size 312 Hearing Aid Battery|
|13, Orange tab, PR48, 7000ZD, ZA13||Orange||7.9 x 5.4 mm||280 mAh||50-55 mAh||67-75 mAh||35-40 mAh||38-42 mAh||Size 13 Hearing Aid Battery|
|675, Blue tab, PR44, 7003ZD, ZA675||Blue||11.6 x 5.4 mm||600 mAh||110-130 mAh||150-200 mAh||83-90 mAh||125-130 mAh||Size 675 Hearing Aid Battery|
Note: Older batteries like size 5 (Red tab, PR63, 7012ZD, AC5, ZA5), size 630 (DA630, 7007Z) and size AC41E (7001Z, PR43) are obsolete and were used in older hearing aid devices and are not listed in the table. Also, Amazon affiliate links in the table open in the new windows, feel free to check them for most up to date offers and prices.
Hearing Aid Batteries Common Chemistry Types
Most common hearing aid battery chemistries are:
- non-rechargeable: Zinc-Air batteries, Alkaline batteries, Silver-Oxide batteries, Lithium batteries.
- rechargeable: Nickel Metal-Hydride (NiMH) batteries, Silver-Zinc batteries, Lithium-Ion batteries.
Zinc-air hearing aid batteries are most common non-rechargeable chemistry type.
Zinc-air batteries feature theoretical voltage of 1.65 volts, although in real life this voltage drop down to ~1.4 volts, but remains rather stable and slowly drops down 1.2 volts.
Most hearing aid devices are design to operate properly using batteries in 1.2 - 1.5 volts. Operating devices using batteries with less than 1.2 volts can cause reliability issues, while using batteries with actual voltage higher than 1.5 volts can even damage these devices.
So, before using other batteries than zinc-air in your device, be sure to read its manual/instructions thoroughly and check what kind of batteries are actually supported.
When compared with other non-rechargeable batteries, zinc-air batteries feature the highest capacity and are thus commonly used in hearing aid devices.
How Long Do Zinc-Air Hearing Aid Batteries Last
Zinc-air batteries use air (oxygen from the air) and after their moist electrolyte dries out, they are dead and must be replaced, regardless if they are discharged or not. So, there are basically two reasons why zinc-air batteries may become dead:
- moist electrolyte: depending on the battery brand, model and size, electrolyte of the zinc-air batteries stays wet/moist for few weeks and zinc-air batteries remain operational for those few weeks.
- hearing aid device current load and use: most hearing aid devices are designed to operate 5-10 days (sometimes more - device dependent) without replacing the batteries. However, the more the hearing aid device is used, the more discharged battery becomes. Also, if the hearing aid device is not used, battery capacity doesn't drop due to the battery being discharged, but due to the moisture loss.
So, when protective tab is removes, zinc-air battery can last, at most, few weeks, regardless if it is used or not.
Shelf life: Good zinc-air batteries from reputable brands have shelf life or 3 years or even more.
Alkaline batteries are type of non-rechargeable batteries that are used in hearing aid devices only when no other battery type is available.
Although these batteries have nominal voltage of 1.5 volts, voltage quickly drops during the use. Also, these batteries have ~5x smaller capacity when compared with the same sized zinc-air batteries.
Alkaline batteries feature shelf life of 3+ years, with some models having shelf life of 7+ years.
Silver-oxide batteries are similar to alkaline batteries, but are better performers. However, silver-oxide batteries should also be used in hearing aid devices only when no other battery type is available.
Silver-oxide batteries have nominal voltage of 1.55 volts, and the voltage is relatively stable during the discharge. Although silver-oxide batteries have larger capacity than alkaline batteries, they still have ~3-4x smaller capacity when compared with the same sized zinc-air batteries.
Silver-oxide batteries feature shelf life of 3+ years, with some models having shelf life of 10+ years. Just to be sure, it is nice practice to have few of these stashed around - just in case.
Non-rechargeable lithium batteries are rarely used in hearing aid devices. These batteries feature 3.0(!) volts, have smaller capacity than zinc-air batteries, but they also feature very low self-discharge rate and they tolerate relatively high pulse discharge currents.
But, their rechargeable 'cousins' are starting to appear in modern hearing aids due to the good capacity, high energy density and large number of charge/discharge cycles.
Nickel Metal-Hydride (NiMH) batteries are rechargeable batteries, having potential to help hearing aid devices users to save some money.
Modern NiMH batteries feature almost no memory effect (no memory effect, according to the most of their manufacturers, but ...), have nominal voltage of 1.2 volts which is slightly lower when the battery is in use.
NiMH batteries are environmentally friendly batteries since they don't contain mercury or other heavy metal pollutant - nonetheless, they must be disposed properly.
When compared with zinc-air batteries, NiMH batteries generally have ~5-6x smaller capacity.
When to use NiMH batteries in hearing aid devices?
If your hearing aid device can run 10+ days on a single zinc-air battery, and it tolerates slightly lower voltage of NiMH batteries, then it is quite feasible to run such device for at least one full day on a single battery charge, even when being used more than average.
And when the day is over, battery can be recharged during the night.
However, high-tech hearing aid devices featuring Bluetooth connectivity have higher power consumption and using NiMH batteries for full day without battery replacement is questionable.
Silver-zinc batteries are type of rechargeable batteries, very similar to non-rechargeable silver-oxide batteries.
Silver-zinc batteries feature open circuit voltage at full charge ~1.85 volts and open circuit voltage at full discharge ~1.55 volts.
Depending on the brand and design, silver-zinc batteries feature ~5x smaller capacity than zinc-air batteries, but they also feature higher voltage, leading to ~4x smaller energy capacity.
We emphasize this 'energy capacity', since some hearing aid devices come with built-in very efficient DC-DC (Direct Current to Direct Current) converters, and voltage auto-sense technology.
For short: if your hearing aid device can operate for 10+ days on a single zinc-air battery, and it accepts silver-zinc batteries, such device can easily run for one full day even when being used far more than average.
Operating life of the silver-zinc batteries in hearing aid devices is around one year, after which they must be replaced.
Silver-zinc rechargeable batteries are mostly used in newer hearing-aid devices as built-in batteries that are used during the day and during the night these devices are kept in the charging stations, where their batteries are being charged - there is no need to remove the battery from the device, unless the battery is being replaced with the new one!
Lithium ion batteries are rechargeable batteries featuring 3.6-3.7 volts nominal voltage. Also, they feature low selfdischarge rate (for rechargeable batteries), good energy density, fade-free power, no memory effect and can be easily charged 500-1000 times, some models even more.
Lithium ion batteries are not as common as zinc-air batteries, but they are being used more and more often, especially in high drain devices.
Lithium ion batteries can last up to 3-4 years, after which they must be replaced and disposed properly.
Like devices that use silver-zinc batteries, lithium ion powered devices are designed to be used for at least a day (sometimes much more) on a single battery charge - during the night, hearing aid device is kept in the charging station and the battery is fully charged.
Most Common Hearing Aid Batteries Sizes
Unless your hearing aid device came with built in silver-zinc or lithium-ion rechargeable battery, your hearing aid device most probably uses one of the following batteries:
Size 10 Hearing Aid Batteries
Size 10 hearing aid batteries, also labeled as Yellow tab, PR70, 7005ZD, AC10, DA10, ZA 10 etc. are button cell batteries 5.8 mm in diameter and 3.6 mm in height.
Regardless of the label, size 10 hearing aid batteries feature YELLOW TABS.
Zinc-air size 10 battery capacity is ~90 mAh, while equivalent NiMH battery capacity is just 11-15 mAh and silver-zinc (AgZn) battery capacity is 15-18 mAh.
Again, before replacing zinc-air batteries with NiMH and/or AgZn, check the documentation of your hearing aid devices if such batteries are supported due to the voltage differences.
For more about these batteries, check Size 10 Hearing Aid Battery Amazon link (link opens in the new window).
Size 312 Hearing Aid Batteries
Size 312 hearing aid batteries are button cell batteries 7.9 mm in diameter and 3.6 mm in height. They are also labeled as Brown tab, PR41, 7002ZD, ZA312, p312, 312A etc.
Regardless of the label, size 312 hearing aid batteries feature BROWN TABS.
Zinc-air size 312 battery capacity is ~160 mAh, while equivalent rechargeable NiMH battery capacity is 20-25 mAh and silver-zinc (AgZn) battery capacity is around 30-32 mAh.
Before replacing zinc-air batteries with NiMH and/or AgZn, be sure to check the documentation of your hearing aid devices if such batteries are supported due to the voltage differences.
7.9x3.6 mm button cell alkaline (labeled as LR41, LR736, AG3 etc) and silver oxide (labeled as SR41, SR736, SR736PW, SR736SW, SG3 etc.) non-rechargeable batteries can be used instead of zinc-air batteries, if required, just note that these batteries have smaller capacity and that alkaline battery voltage is lower than zinc-air battery voltage. Slightly higher voltage of silver-oxide batteries is rarely of an issue, but just in case, check the documentation of your device.
For more about these batteries, check Size 312 Hearing Aid Battery Amazon link (link opens in the new window).
Size 13 Hearing Aid Batteries
Size 13 hearing aid batteries are button cell batteries 7.9 mm in diameter and 5.4 mm in height. They are also labeled as Orange tab, PR48, 7000ZD, ZA13 etc.
Regardless of the label, size 13 hearing aid batteries feature ORANGE TABS.
Zinc-air size 13 battery capacity is ~280 mAh, while equivalent rechargeable NiMH battery capacity is 35-40 mAh and silver-zinc (AgZn) battery capacity is around 38-42 mAh.
Again, before replacing zinc-air batteries with NiMH/AgZn batteries, be sure to check the documentation of your hearing aid device.
Physical dimensions of size 13 (Orange tab) and size 312 (Brown tab) hearing aid batteries are similar - both models are 7.9 mm in diameter, with 5.4 mm (size 13, Orange tab) and 3.6 mm (size 312, Brown tab) in height. This ~1.8 mm height difference leads to more than 50% higher capacity - if your hearing aid device support the use of size 312 (Brown tab) batteries, and the batteries last too short, check the documentation to see if the size 13 batteries are supported too.
For more about these batteries, check Size 13 Hearing Aid Battery Amazon link (link opens in the new window).
Size 675 Hearing Aid Batteries
Size 675 hearing aid batteries are button cell batteries 11.6 mm in diameter and 5.4 mm in height. They are also labeled as Blue tab, PR44, 7003ZD, ZA675 etc.
Regardless of the label, size 675 hearing aid batteries feature BLUE TABS.
Size 675 (Blue tab) hearing aid devices are the largest common zinc-air hearing aid batteries and feature the largest capacity.
Zinc-air size 675 battery capacity is ~600 mAh, while equivalent rechargeable NiMH battery capacity is ~90 mAh and silver-zinc (AgZn) battery capacity is ~130 mAh.
Again, due to the voltage differences, before replacing zinc-air batteries with NiMH/AgZn batteries, be sure to check the documentation of your hearing aid device.
These batteries can be replaced with alkaline (labeled as LR44, 76A, AG13, LR1154, A76 etc) or silver oxide (labeled as SR43W, SR43, SR43SW, 386, 301 etc.) batteries, just be sure to check if you device support the use of such batteries due to the voltage differences.
For more about these batteries, check Size 675 Hearing Aid Battery Amazon link (link opens in the new window).
Long Story Short: when replacing your hearing aid batteries, always check the list of battery types supported by your device.
Zinc-air non-rechargeable batteries are practically standard hearing aid device batteries, featuring good capacity, stable voltage and acceptable price.
If supported, NiMH and AgZn batteries are rechargeable alternative to zinc-air batteries, but they suffer from lower capacity and must be often replaced from the unit and recharged using chargers in the form of USB sticks (with or without wall adapter).
Hearing aid devices that come with built-in AgZn and lithium ion rechargeable batteries often feature small charging station where hearing aid devices are stored during the night and charged. Built-in AgZn batteries can last up to or even more than one year, while lithium-ion batteries can last up to 3-4 years.