As I have already told you on occasion, for various reasons, I have more headphones than ears, so it is not strange that some remain at the bottom of the drawer and are not used for months.
That is what happened to me with some Panasonic RZ-S300, some TWS Bluetooth earphones that I had almost forgotten, but when I sorted the drawer I discovered it again and I thought it sold well to put them in context and compare them with the Sony WF-C500.
However, when trying to put them to work, the battery did not respond. They had been without use for several months, so it is normal that they did not have a battery, so I connected them to a USB to charge the case.
My surprise was that it did not show signs of life, not even changing the cable, connecting it directly to different chargers or leaving it on charge for several hours. the headphones were dead -or rather its charging case had passed away—and nothing could be done for them.
Intrigued by the event, I decided to ask on the networks to see if it had happened to anyone else and…surprise!! I didn’t have to go far because something similar had also happened to some of my colleagues with headphones of different brands and models.
Why have my Bluetooth headphones stopped working?
They say that curiosity killed the cat. I am not a cat, but out of curiosity I have plenty, so I could only pull contacts to try to find out what internal process had caused the battery to become unusable and without the possibility of reloading normally.
I spend with headphones for being a device with a relatively small battery, but it could happen to practically any device with a battery, since It is a problem inherent to the operation of the battery and totally random..
Marc Bara, professor at OBS Business School, comments: “Rechargeable batteries use a complicated chemical mechanism to store electrical energy. Found in most wireless headphones and other portable devices, lithium-ion batteries degrade the positive and negative electrodes as lithium ions migrate during charging and discharging. This process can result in the buildup of unwanted materials in the battery, limiting its charging capacity and longevity.”.
Professor Bara gave a good point that would explain, for example, that the headphones were reducing their autonomy in hours of use, progressively lowering the 8 hours of music that they offered when they were new. Something that you have probably already experienced with your smartphone, laptop or tablets when you have been using them for a couple of years.
Simply, the battery lasts less. But that was not the case. My Bluetooth headphones hadn’t seen that wear and tear, as they they had spent the last few months unused in a drawer.
Crystallization: the silent enemy for the batteries of your devices
My profession allows me to meet brilliant people who develop many of the products and devices that months or even years later end up in the pockets of millions of people. The key that has solved the mystery was given by a responsible for battery development at a major tech company who has asked to remain anonymous.
According to what this anonymous source who is an expert in the matter tells me,”[…] The battery is made up of an electrolyte inside that acts as a base on which the electrons that move between the anode and the cathode of the battery float depending on whether it is being charged or discharged.”.
“The problem is that the cathode material inside the battery could continue to react with the electrolyte in small amounts in a “battery self-consumption” process, and even when the device is not in use, this power consumption behavior is a reaction. continuous chemistry”.
“The battery is fully charged to 4.4V, over time the voltage will drop by the self-consumption process we have mentioned down to about 0.7V. This voltage change will lead to the reaction between the positive electrode material and the electrolyte to produce insoluble products that materialize in the form of crystallization that cancels its function and causes irreversible damage, that is, the death of the battery”.
So the problem is that even though you are not using the headphones (or any other battery powered device) inside it the chemical processes continue and that can create a film of crystals that prevent the normal operation of the charge and discharge poles.
What can I do to prevent my headset battery from dying?
As this source comments, the key is that continued self-consumption lowered the voltage damaging the positive electrode, so one of the keys will be to ensure that this voltage never drops too low for a long time.
From Nothing, the brand founded by the charismatic Carl Pei, and one of the ones that is betting the most on Bluetooth headphones lately with three models in its still young catalogue, they give us some recommendations for take care of the battery of your headphones and prevent them from dying.
1. Don’t let the battery run out for a long time
The first recommendation is keep battery charged preventing it from spending weeks unloaded. That is, nothing happens if you rush the charges of the case to the maximum. It is for that.
However, it is not convenient to leave the case without charge for weeks or months favoring the fatal crystallization of the electrodes. One way to avoid this is by making occasional charges to the headphones even if you are not using them. Thus, the voltage level is maintained.
2. Keep them at a suitable temperature
Ambient temperature also contributes to accelerate crystallization in the battery. It is recommended to keep them between 0 and 35 degrees and between 45% and 75% humidity.
As Professor Marc Bara reminds us, “Both hot and cold temperature extremes can have a severe impact on battery performance and capacity. Last but not least, even if you don’t use it the battery loses capacity over time”.
3. Always keep them clean and dry
Moisture can damage the metal contacts of the case or headphones, generating false contacts and even preventing them from charging correctly.
Sweat, or moisture from condensation, can go unnoticed when the earphones are used frequently and aired out, but can pose a risk when kept locked inside the case.
Professor Bara also recommends keep the wireless headphones clean and dry when they are to be stored for an extended period of time.