You will need
- charger., stopwatch.
Buy, hire or borrow a special device to measure capacitance of the battery. Take the battery and fully charge it, then discharge it using the current (I). Measure the time (T) during which it will discharge.
Calculate the product of current, which will be the capacity of the battery. To do this, take the amperage and time, and multiply (Q = I*T). I note that in the same way you can measure the capacity of any battery, and regular batteries. But it should be remembered that the simple battery charge again, unlike a battery, it will be impossible.
In order to know the capacity of the battery, you can use other methods. So to measure the capacity of the specified device, you can use a special scheme that allows you to discharge the battery through the resistor (R). Moreover, such a discharge is performed to a voltage of approximately 1W. Then measure the discharge current according to the formula: I = U/R.
To measure the discharge time, you can use an ordinary watch, capable of working at 1.5 watts. When you discharge the battery, remember that the device should not be discharged completely, and for this it is necessary to use special solid relay, for example, PVN012. This relay allows time to disconnect the battery at the moment when the voltage drops to a minimum level. Allowed the reduction to 1W, as already noted.
Connect the discharged battery to the circuit. Enable the profile and set the stopwatch include clock. When the discharge reaches 1 W, the relay will close and clock will stop.
To see how much charge it loses battery after about a week or two of use, when discharge, it is necessary to measure the capacity of the device after it is fully charged and make such measurements after another week or two.