No. 3. 1.340 specific gravity sulphuric acid, 15.5 per cent sodium sulphate.
No. 4. 1.290 specific gravity sulphuric acid, 1.5 per cent sodium sulphate.
No. 5. 1.300 specific gravity sulphuric acid.
If such "dope" electrolytes are added to a discharged battery, the subsequent charging of the battery will add more acid to the electrolyte, the specific gravity of which will then rise much higher than it should, and the plates and separators are soon ruined.
Do not put faith in any "magic" solution which is supposed to work wonders. There is only one way to charge a battery, and that is to send a current through it, and there is only one electrolyte to use, and that is the standard mixture of distilled water and chemically pure sulphuric acid.
[7. The specific gravity of the electrolyte should be measured] every two weeks and a permanent record of the readings made for future reference.
The specific gravity of the electrolyte is the ratio of its weight to the weight of an equal volume of water. Acid is heavier than water, and hence the heavier the electrolyte, the more acid it, contains, and the more nearly it is fully charged. In automobile batteries, a specific gravity of 1.300-1.280 indicates a fully charged battery. Generally, a gravity of 1.280 is taken to indicate a fully, charged cell, and in this book this will be done. Complete readings are as follows:
1.300-1.280--Fully charged.
1.280-1.200--More than half charged.