Electrolyte Density Check
In combination with voltage measurement, the actual density of the electrolyte allows you to draw a conclusion about the degree of discharge of the battery.
A battery densimeter with a pipette is used for testing. The greater the specific gravity (electrolyte density) sucked electrolyte, the deeper the float sinks (hydrometer). On a scale, you can read the density of the electrolyte in the form of specific gravity (g/ml) or degrees Baume (+°Be).
The following values must be reached (at an electrolyte temperature of about +20°C).
The degree of discharge of the battery | +°Be | g/ml |
Discharged | 16 | 1,15 |
half empty | 24 | 1,22 |
well charged | 30 | 1,26 |
Check each individual cell in sequence, all cell cells must have the same electrolyte density (maximum difference 0.04g/ml). Otherwise, the faulty battery may short out.
Battery test under load
1. Connect a voltmeter to the battery terminals.
2. Note: If the battery voltage (without consumer connection) less than 12 V, it is discharged and needs to be recharged.
3. Start the engine and read the voltage.
4. In the process of starting the engine, a charged battery must have a voltage of at least 8 V (at an electrolyte temperature of about +20°C).
5. If the voltage drops immediately and different electrolyte densities were recorded in the cells, then the faulty battery may close.
The total voltage can be measured with a battery tester. Pay attention to the manufacturer's recommendations for battery care.
Reference values
Battery capacity, Ah | Load current, A | Minimum voltage after 5–10 sec. at t 0–20°C |
62 | 190 | 10.0 V |
74 | 265 | 10.0 V |
100 | 300 | 10.0 V |
Attention! If during this measurement (duration 10 sec.) the total voltage drops below 10 V, the battery is either discharged or defective.