Performance test of hearing aid batteries of 25 brands was carried out by Pensioners News between January 2018 and April 2019. The batteries were of size 13 and 312.
The tested batteries were bought from Finnish hearing aid shops, departments stores, drugstores and European and Chinese online stores.
In July 2013 Laboratory of Acoustics at the Department of Otorhinolaryngology (IAO) published a study on hearing aid batteries of sizes 675, 13, 312 and 10. The publication ” Performance analysis of ten brands of batteries for hearing aids” can be read in the Internet . In the study performance of batteries from 10 manufacturers was measured .
In Hearingtracker.com blog ”Hearing Aid Batteries – How Long Do They Really Last?” hearing aid users have discussed the duration of hearing aid batteries based on their experience
In th present study as in the IAO measurements batteries were discharged by connecting a 1500 Ohm resistor between the positive pole and negative pole of the battery. Voltage of the batteries being discharged was measure with a 16 channel Picolog 1216 datalogger connected to a computer. As accuracy of the datalogger is 12 bits the accuracy of the measurements is about 12 mV.
Battery seals were removed from batteries and the batteries were then left for 10 minutes for activation. Measurements were carried out on at least three samples of each battery. Temperature during the measurements was 21 to 22 degrees Celtigrade.
Data was collected every 10 minute with a computer. In the IAO study batteries we discharged for 12 hours whereafter the load was disconnected and the batteries were allowed to rest for 12 hours without load. In the present study the batteries were discharged continiously.
Capacity of a hearing aid battery can be expressed as milliamperehous mAh. According to battery manufacturers size 13 hearing aid batteries have a capacity of 280-310 mAh and size 312 batteries have a capacity of 160-180 mAh. Capacity of hearing aid batteries is calculated from voltage, resistance and time till the voltage of a discharged battery has dropped to 1,1 V
Figure 1 shows the tested batteries.
Results of the measurements are collected in Table 1. For each battery the table contains ”Best Before” date, calculated capacity and time in days till voltage of the battery has dropped to 1,1 V at which voltage hearing aids tend to stop working. The values are average values calculated from at least 3 measurements on each battery. Also origin of the batteries is given if known.
Graphs in figure 2 show voltage during the discharge of one size 13 battery and one size 312 battery. Figures 3 to 8 show the voltage graphs (discharge curves ) of all measured batteries. End voltage in these graphs is limited to 1.1 V to make it easier to visualize differences between the batteries.
The five best batteries are highlited with green background. The time in Table 1 of various batteries to maintain voltage during discharge above 1.1 V is not a direct indication of for how long a battery keeps an individual hearing aid running as this depends on the power consumption of the hearing aid, needed volume amplification etc. The results of the measurements yet give information on differences between the tested batteries. No estimates on the cost effectiveness of the batteries is made as the price of hearing aid batteries varies a lot depending on the amount of batteries bought and on from where the batteries are bought.
Dr. Arto Sivola, Senior Researcher