Ford Fiesta: Battery, Mounting and Cables / Battery and Cables - System Operation and Component Description. Description and Operation

System Operation

Battery and Cables

The battery is a 12V DC source connected in a negative ground system and is a voltage stabilizer for the 12V electrical system.

Vehicles with 1.0L EcoBoost or 1.6L EcoBoost engine have a battery monitor sensor attached to the negative battery cable.
Refer to: Charging System - 1.6L EcoBoost (132kW/180PS) – Sigma - System Operation and Component Description (414-00 Charging System - General Information, Description and Operation).

NOTE: The primary purpose of the battery eye is to be a quick indicator of the battery's state-of-charge for assembly plants and dealership pre-delivery processes.

The battery eye indicates the battery state-of-charge by responding to the specific gravity of a single battery cell electrolyte. The battery eye has a viewing plate, 2 colored balls of different specific gravity and a small passage. As the battery's state-of-charge and specific gravity changes, the balls change their position in the passageway and display a different color in the viewing eye.

Do not install a new battery based only on the battery eye color. The battery eye color simply indicates the battery state-of-charge, not its condition. For example, a red or yellow/black battery eye usually indicates the battery is discharged, not defective. If the battery eye indicates the battery may be discharged, recharge the battery before testing its condition.

• Red - low state-of-charge
• Yellow/Black - between high and low state-of-charge
• Green - high state-of-charge
• No color can occur after the battery has been in service for several years and some of the plate material has coated the balls
• A clear battery eye can occur if the battery case becomes damaged and the electrolyte has fallen below the plates