Charging a sulphated battery at high rate results in

The correct answer is D. all above.

Charging a sulphated battery at high rate results in:

• Boiling of electrolyte due to gassing: When a battery is charged, the electrolyte (a mixture of sulfuric acid and water) is converted into water and sulfur dioxide gas. If the battery is charged at a high rate, the electrolyte will boil, causing the battery to overheat.
• Warping of plates: The plates in a battery are made of lead and lead dioxide. When a battery is charged, the lead sulfate on the plates is converted back into lead and lead dioxide. If the battery is charged at a high rate, the heat generated can cause the plates to warp.
• Damage to separators, cell caps covers and battery case due to excessive temperature: The separators in a battery are made of a material that allows the electrolyte to flow between the plates, but prevents the plates from touching each other. If the battery is charged at a high rate, the heat generated can cause the separators to break down. The cell caps covers and battery case are made of plastic or metal. If the battery is charged at a high rate, the heat generated can cause these components to warp or melt.

It is important to charge a sulphated battery at a low rate to avoid these problems.