Here you can see in detail. A full cycle of maintenance of an unattended battery:
measuring the internal resistance of the battery and voltage,
measuring the density
of the electrolyte, adding distilled water to the battery,
adjusting the density of the electrolyte,
making a device for soldering plastic,
soldering holes in the battery housing,
comparing all parameters at different stages of battery maintenance.

Distilled water is FREE. Complies with GOST.   • Дистиллированная вода БЕСПЛАТНО. Соот...  

I charged the old battery Berezhok V 1    • Заряди старый аккумулятор #БережокV1  

Charge the battery with a pulse Save your battery    • Заряди аккумулятор импульсом Спаси св...  

Add "IT" to the charger    • Добавь "ЭТО" в зарядное устройство  

And you have charged your battery to 100%. Car Charger Berezhok V1    • А ты зарядил свой аккумулятор до 100%...  

Flashing the KONNWEI 650 battery Tester    • Перепрошивка аккумуляторного тестера ...