How to determine the battery capacity of headphones?

Question

Batteries

I bought wireless headphones. It turned out that they are quite quickly discharged. Obviously a bad battery. I opened it, hoping that there would be at least some kind of marking. It turned out, nothing, no volt-ampere characteristics, no volume. How to determine them with a multimeter?
In addition, the headphones do not have a name or model. But some components are somehow signed, is it possible to find the battery capacity among them by finding their datasheets?

Answer 1

The real capacity can be found out by controlled discharge / charge of the battery - which is what the so-called "battery testers" do.
Simply put, a fully charged battery is connected to a load that provides a discharge current of 100mA (for example) and its discharge time is measured.

Answer 2

the easiest way is to find a new battery in size, the same battery will give about the same power.
the discharge characteristic of an old dead battery will not say anything about the real initial capacity.

Answer 3

Take any lithium battery that will fit. I pumped the headphones like this, putting a four times larger battery, worked for two weeks without charging. VAC will not give you anything, the usual 3.7v Chinese lithium.

Answer 4

CVC is a purely academic parameter that does not give anything for everyday practice. But the capacity, and even a multimeter ... They already answered how to do this. Therefore, I will add another method, indirect, which is only suitable for charging via USB. Connect your headphones for charging through such a device , and it will show you the charging capacity. Multiplying it by the efficiency of the battery, you get the discharge you need . The efficiency of a lithium battery is approximately 0.8 ... 0.95 (decreases as the service life increases).