LIDL Solar Mole Repellent: Weakening Sound Waves Due to Low Temperature - Comparisons & Reasons

On March 27, in the LIDL shop, I bought a solar scarecrow.
After switching on the repeller, the buzzer in the device started to emit sound waves (batteries charged). After depositing it in the ground (temperature in the 5 ° - 7 ° hole) after 2 - 3 minutes, the sound of the signal drops by 40 - 50% and is almost inaudible. After removing the repellent from the ground and waiting for a few minutes the device emits the proper sound waves again (when the temperature in the buzzer will increase). The instructions show that the device can also be used in the winter, that is at low temperatures of the earth (they state "the solar collector was not soiled and covered in winter with snow or ice"). When the repeller is standing in a cold room (gazebo) overnight it is the same.
The reduction of the emitted signal due to the low temperature in the hole does not occur in other solar mole repellent products that I have (other companies).
Please explain the reasons for the weakening of the signal.
It's his picture

Poor quality battery, just what if it is placed in the handle.

Or, if the buzzer has the form of a motor with a weight on the shaft, the grease thickens in it enough that it can not spin.

Rather, it's not the fault of 2 batteries because they are on the surface - in this round sphere, which as the sun shines is warm. How does the buzzer work - the sound wave signaling device I do not know.

Electronic generator plus piezo transducer.

Ok. And what is the reason that at low temperature emitted sound waves are weakening. I would like to know if this is a defect of this device. Tomorrow, I made an appointment to return him to the store.

Is it a repeller's fault that the sound signal emitted becomes weak due to low temperature ??

Rather yes - it is a device designed to work in weather conditions, where such temperatures are not uncommon. If it starts to work worse, it means that there is either a copy or the entire project.

Or maybe he was designed to work on the fields near Canton and a dishonest or incompetent importer chose such because they were the cheapest?

I returned this "scrap" to the store. Or maybe someone will provide information on the solar mole repellent in which you can replace the batteries, has a sound signal switch and in addition to the sound waves emitted there are also vibrations of the arrowhead.

I have found that buzzers in the deterrents have a technology sticker on themselves with the word "take off after washing" in English. This shows only the low level of companies assembling it to the pile. It barely moaned.

But to the point ... I fought with the mole for a month:
1. tube sockets fi 50 and fi 75 - without effect
2. burying the contents of the cat litter box - to no avail
3. Chatting with a shovel - no effect

It helped wunder waffe in the form of firecrackers popularly called "achtungi"

I have cleared the holes of the mounds. Achtung inside and covered with a lid from the barrel to increase the sound pressure in the tunnels As it slipped smoke in the hole for 15 minutes was like in a boiler room. I repeated the maneuver in three holes.

Crete is gone. It must have stunned him completely until he fell.
And I warn you that fighting a mole in a fenced area is legal.

It is a waste of time for patentsors from the net