A penny device that is more convenient than a multimeter and is quite suitable as a utilitarian gift.
Why check batteries
There are three reasons why a battery that is still running may be left out of service:
1. Only one defective battery in a bunch has "died", because of which it seems that the whole set is "exhausted".
This is not uncommon, especially when cheap batteries are bought. You insert a set of four into the device, it works for a while, then the batteries seem to run out. But during the check it turns out that in reality only one “died” due to factory defects, and the rest worked out their resource by 15%.
2. A gluttony device does not consume battery power until the end.
There are still cases when the batteries are used in a very voracious electronic device that may not fully use them. A specific example is a Furby toy. It starts to fail when another third of the energy reserve is left in the batteries.
Accordingly, these batteries can be used in some other place, which is not so demanding on the residual resource.
Why it happens?
As the battery charge decreases, its voltage decreases. A full-charge finger-type battery gives a voltage of about 1.55 V, and a battery that has dropped to 0.9 V can be considered a dead battery.
This is how the discharge graphs of salt and alkaline (alkaline) batteries look like:
According to my observations, most devices will stop working or will not work satisfactorily when the voltage drops to 1.1 V.
3. Slightly oxidized contacts give the impression of a dead battery.
You get a dead battery, but when you check it turns out that it is still quite working. The reason, most often, lies in the slightly oxidized contacts, on which the resistance increases, respectively, the voltage and current begin to fall.
BT-168D Battery Tester
This is the cheapest appliance on Aliexpress. The price tag with delivery to the Russian Federation starts from 180 rubles, but with rare luck you can find for ~ 130.
Why can not you take even cheaper voltmeters there? One nuance will come up with them – the minimum voltage for measurement is 2.5 volts or more (if we are talking about models without an internal power source). At lower voltages, they simply do not turn on. Therefore, it is better to immediately pay attention to specialized options.
I collected some characteristics of the device in a plate, some of which I received during its verification:
Types of batteries tested
– almost all 1.5-volt cells, ranging from “tablets” to “barrels” LR20
– 9-volt "crowns" (6LR61 / 6F22)
Minimum voltage to enable a 1.5-volt input
~ 0.55 V
Minimum voltage to turn on the 9-volt input
~ 6 V
Maximum length of 1.5 volt cell
Regarding starting voltages, if the appliance did not turn on when the battery was connected, then the voltage on it is below 0.55 V for one-and-a-half-volt cells or 6 V for Kron.
It measures the voltage relatively accurately, but there is a nuance related to the underestimation of the readings of the real voltage on the finger batteries by 0.05 V. Most likely this is due to the fact that the device itself is powered by it and creates a load at the time of measurement, which does not seem to adjusted.
But if you discard the subject with the adjustment, then the readings will be quite accurate.
On the back of the memo.
In general, I agree with her. According to my long-term observations, a 1.5-volt battery can be considered as shrunk if it produces less than 1.1 V. Most electronic devices no longer want to work with such sources, and the LCD screens of all kinds of watches and thermometers become faded.
Of the disadvantages of the tester – freely sliding contact foot, which presses the battery. It would be nice to spring it, so that during the measurement you do not have to press it all the time with your hands. However, some craftsmen fix this "bug" on their own:
You can find such a tester on Ali, for example, here. And since many people here have full-fledged multimeters on the farm, such a “toy” can be a good gift to someone from relatives.