Electrolyte check
1. Make sure the electrolyte level is between the marks "UPPER" And "LOWER".
If the level is below the mark "LOWER" add distilled water. Don't fill it all the way.
2. Measure the density of the electrolyte using a hydrometer.
If the density of the electrolyte is less than the nominal, charge the rechargeable battery.
- Nominal density (at 20°C) — 1.27-1.29g/cm3
