Maintenance and testing of the battery (Mitsubishi Colt 4)

Weekly battery maintenance includes checking the electrolyte level in each cell (can) to ensure that the separator plates are covered with electrolyte to a depth of 6 mm above their top edge.

If the electrolyte level has dropped, add only distilled water. Do not allow overflow. If this has happened or some electrolyte has spilled, wipe it off immediately and rinse the area with water and soda, as the electrolyte is very aggressive, and when in contact with metal, the latter corrodes strongly.

In addition to keeping the battery contacts clean and coated with petroleum jelly, the top cover of the battery, especially the top of the cell cans, should be kept clean and dry. This prevents corrosion and partial self-discharge of the battery due to moisture and dirt.

Every three months, remove the battery and inspect the battery mounting bolts, mounting plate, tray and cables for corrosion (white fluffy deposit on metal, brittle to the touch). If corrosion is found, clean off the deposits with ammonia and coat the cleaned metal with an anti-rust agent or primer.

if there are excess deposits on the top of the battery, this may be due to cracks in the case, which cause electrolyte leaks or overcharging of the battery, which indicates the need to check the voltage regulator in the workshop.

When checking the battery every three months, check the density of the electrolyte using a hydrometer to determine the state of charge of the battery and the condition of the electrolyte.

[The text of the article was taken from the website: www.MitsubishiMan.ru]

Fill the hydrometer with electrolyte through a special hole on the battery case. At the same time, measure the temperature of the electrolyte. If the electrolyte level is low, tilt the battery to make the measurement easier.
Convert the density of the electrolyte at a given temperature to the density at a standard temperature of 20°C.

Example: electrolyte temperature 35°C measured density 1.230. Reduced density will be 1.240.

There should be a very small difference between different cans, and if the difference exceeds 0.025 g/cm³, the reasons for this may be the following:

loss of electrolyte from a battery caused by splashing or leakage which can lead to a decrease in the specific gravity of the electrolyte when the lack of electrolyte is compensated for by adding distilled water instead of fresh electrolyte;
an internal short circuit caused by bending of the plates or something similar will cause the entire battery to malfunction and inevitably fail soon. The density of the electrolyte at various temperatures for a fully charged battery is shown in Table A. The density of the electrolyte of a fully discharged battery at various temperatures is shown in Table B.

Elements of the device for checking the correction of the density of the battery electrolyte and the density of the coolant (antifreeze)
1 - hydrometer for checking the density of battery electrolyte; 2 - hydrometer for checking the density of the coolant; 3 - funnel; 4 - extension cord; 5 - glass tube; 6 - glass rod; 7 - container with a rubber bulb; 8 - case.