Maintenance-free (MF) batteries — key characteristic for servicing Which statement best describes the main service characteristic of a maintenance-free (MF) automotive lead–acid battery?

Introduction / Context:
MF batteries are widely used in modern vehicles to reduce user maintenance. Understanding what “maintenance-free” actually implies prevents improper servicing.

Given Data / Assumptions:

• Sealed, valve-regulated or low-water-loss lead–acid battery design.
• Correct charging voltages and temperatures maintained by vehicle regulator.
• No visible filler caps for routine topping up.

Concept / Approach:
MF batteries minimize water loss by using improved grid alloys, recombination of gases, and sealed designs. Under normal charging, water consumption is extremely low, so periodic topping up is not necessary. They still require correct charging and can be recharged using appropriate chargers.

Step-by-Step Solution:

Verification / Alternative check:
Manufacturer datasheets specify “no topping up required under normal service” and provide charging profiles instead of electrolyte maintenance procedures.

Why Other Options Are Wrong:

• Adding plain water routinely: not required; also electrolyte concentration must remain correct.
• Shorter shelf life: typically equal or better if stored properly.
• Recharging impossible: false; MF batteries are rechargeable lead–acid cells.
• Monthly acid top-ups: incorrect and dangerous.

Common Pitfalls:
Overcharging which vents gas and shortens life; using unregulated chargers; opening sealed plugs voiding warranty.

Final Answer: