🔍 Key Concepts

• GMDSS battery charger modes and why "high" or "boost" charge can be risky for certain chemistries • Differences between flooded lead-acid, gel/maintenance‑free lead-acid, Ni-Cd, and lithium-ion charging requirements • Manufacturer and SOLAS/GMDSS emphasis on avoiding overcharge and gassing for some sealed battery types

💭 Think About

• Which battery type is most sensitive to overvoltage and gassing because the electrolyte cannot be topped up or vented easily? • On a ship’s GMDSS station, which battery type is most likely to be sealed/maintenance‑free and therefore needs a gentler, tightly controlled charge instead of a full/high boost charge? • Think about which battery types are commonly used today for GMDSS installations and what their recommended charging regime looks like in the manufacturer’s manual.

✅ Before You Answer

• Identify which option describes a sealed/maintenance‑free battery where water loss from gassing cannot be corrected by adding electrolyte. • Consider which battery type’s manual usually specifies no high‑rate boost charge or warns about damage from overcharging. • Eliminate any battery types that are normally designed to tolerate periodic equalize or high‑rate charging.