Checking specific gravity of electrolyte of all cells — AUDI

Special tools and workshop equipment required

Commercially available hydrometer

Attention:
Always pay attention to accident prevention regulations when handling electrolyte. Appropriate protective clothing must be worn.
When disposing of batteries, always pay attention to the appropriate regulations for batteries and sulphuric acid.
Notes:

In conjunction with the battery load test, testing of the specific gravity of the electrolyte provides information on the condition of the battery.
The temperature of the electrolyte must be at least 10°C.
Specific gravity of electrolyte can be checked immediately after charging battery.

Test sequence

Screw out all battery cell caps.
Immerse hydrometer in one of the cells and draw in electrolyte until float is freely suspended in electrolyte.
The greater the specific gravity of the electrolyte drawn in, the higher the float will ride.
The specific gravity in kg/dm3 can be read off from the hydrometer scale.

Take reading on hydrometer and compare it to values given in table.

Charge state in normal climatic zones · Specific gravity / of electrolyte in / kg/dm3
Discharged · 1.12
Semi-charged · 1.20
Well charged · 1.28

Charge state in the tropics · Specific gravity / of electrolyte in / kg/dm3
Discharged · 1.08
Semi-charged · 1.16
Well charged · 1.23

The specific gravity in normal climatic zones must be at least 1.24 kg/dm3.

Charge battery if specific gravity is too low in all battery cells.
Repeat testing of electrolyte specific gravity after charging battery.
Replace battery if readings do not match specifications.

Note:

The measured values for the electrolyte specific gravity of the individual battery cells must not deviate by more than 0.03 kg/dm3, otherwise battery is to be replaced.

Battery cell: · 1 · 2 · 3 · 4 · 5 · 6
Specific gravity of electrolyteper cell / in kg/dm3
Example 1: · 1.24 · 1.25 · 1.25 · 1.10 · 1.24 · 1.25
Result: Specific gravity in cell 4 is too low (deviation greater than 0.03 kg/dm3)
Example 2: · 1.26 · 1.26 · 1.25 · 1.14 · 1.18 · 1.24
Result: Specific gravity in cells 4 and 5 is too low (deviation greater than 0.03 kg/dm3)

Screw caps back in again if readings match specifications.

Attention:
To ensure that the various battery cover systems do not leak, only screw genuine battery caps into battery openings. In the event of loss or damage, make exclusive use of genuine caps of the same type.
The caps must be fitted with an O-ring seal.