EGSA Battery and Starting Systems 2

Question 1

A battery charger for a standby generator is typically sized at what percentage of the battery's amp-hour (Ah) capacity?

Accepted Answer

5% to 10%

Answer

Battery chargers for standby applications are generally sized at 5% to 10% of the battery's Ah capacity to provide adequate float and recharge capability without overcharging.

Question 2

What hazardous gas is produced during the charging of flooded lead-acid batteries that requires adequate ventilation?

Accepted Answer

Hydrogen

Answer

Flooded lead-acid batteries produce hydrogen gas during charging through electrolysis; hydrogen is highly flammable and can form explosive mixtures with air, requiring ventilation to prevent accumulation.

Question 3

What is thermal runaway in a VRLA battery, and what typically triggers it?

Accepted Answer

A self-reinforcing condition where increasing temperature causes increasing current, leading to battery destruction

Answer

Thermal runaway occurs when elevated battery temperature reduces internal resistance, causing more current to flow, which generates more heat in a destructive feedback loop that can result in battery failure or fire.

Question 4

How does low ambient temperature affect a lead-acid battery's available capacity?

Accepted Answer

Capacity decreases significantly as temperature drops below 32°F (0°C)

Answer

Cold temperatures increase electrolyte viscosity and slow electrochemical reactions, significantly reducing available capacity — a battery may deliver only 50% of its rated capacity at 0°F compared to 77°F.

Question 5

What instrument is used to measure the specific gravity of electrolyte in a flooded lead-acid battery?

Accepted Answer

Hydrometer

Answer

A hydrometer measures the density (specific gravity) of the electrolyte relative to water, which directly correlates to the state of charge of a flooded lead-acid battery cell.

(EGSA) Electrical Generating Systems Association Certified Practice Test

(EGSA) Electrical Generating Systems Association Certified Practice Test

EGSA Battery and Starting Systems 2