Quartz watch battery how to detect quartz watch battery capacity

Unlike normal dry cells, the discharge curve of the silver oxide cell is very flat. It does not behave like a dry cell and the voltage decreases with use (see photo). This is of course good for keeping the accuracy of the travel time of the quartz watch . But it also poses a problem that can not be measured by the voltage to determine how much battery capacity left, the nominal voltage of silver oxide batteries are basically 1.55V, and this voltage will remain until the end of the battery life.

Once the battery voltage starts to drop, its service life will soon be reached. Therefore, in order to avoid affecting the normal wear of the quartz watch , many quartz watches are equipped with a battery voltage warning function, which is stopped by the seconds hand for 4 seconds and then quickly jump 4 times down Said that once this phenomenon occurs, the quartz watch can walk around 10 days or so, to remind you to replace the battery immediately. This feature is also called "EOL", but there is no center second hand quartz watch , there is no such function.

In fact, like all batteries, the new battery capacity is not exactly the same, the unit of battery capacity is expressed in milliamps per hour (maH). So far, I have not heard of an instrument that can quickly, non-destructively and accurately detect the capacity of a silver oxide battery. As early as 20 years ago, I heard that foreign countries have already rewarded this equipment heavily Inventions, but up to now no one can do it.

Battery manufacturers in the battery factory quality inspection, are still used in batches of battery discharge experiment, is to test the battery connected to a load, the formation of a closed circuit current, until the battery voltage is reduced to a certain value, with Discharge current multiplied by the discharge time is the actual capacity of the battery. When the experiment is over, the battery is scrapped.

Now rapid detection of quartz watch batteries are heavy-duty discharge, see the battery under different discharge current, pressure drop, because with the use of the battery internal resistance (also known as the battery internal resistance) will be increased; So once the discharge current increases, the closed-circuit voltage will drop suddenly.

Like some Swiss quartz calibrators, all have heavy duty discharge tests with load resistance of 2000 ohms, 50 ohms and 5 ohms (see photo). In fact, the watch silver oxide batteries also have different uses, such as high current output type and low current output type, their electrolytes are different, the former is usually used for LCD quartz watch with a lantern trouble, the latter for the pointer Quartz watch on.

When the button is pressed, the load resistance is turned on, immediately observe the extent of the battery voltage drop, different batteries should have different indicators, but in general the voltage can not be less than 1.35V.

The size of the cross-sectional area of the battery, the test temperature and the test results, the larger the battery, the ambient temperature is higher, the voltage drop less.

Battery heavy load experiment, only about its estimated capacity under the battery, but can not achieve the numerical precision measurement, but this experiment can not be done for a long time, because it is more battery power consumption.