Battery Electrolyte (Battery Acid)
Battery electrolyte is the dilute sulphuric acid inside a lead-acid battery that lets it store and release electrical energy.
What is Battery Electrolyte (Battery Acid)?
In AGM batteries the electrolyte is soaked into glass-fibre mats; in gel batteries it is thickened. In flooded batteries its density, measured with a hydrometer, shows the state of charge. Sealed batteries are designed never to need topping up. White or green crust on battery terminals comes from acid fumes and corrosion.
How it works
During discharge the acid reacts with the lead plates to form lead sulphate; charging reverses the reaction.
Why it matters for your car
Electrolyte burns skin and eyes; wear gloves and goggles and rinse any splashes with plenty of water. Never add acid to a battery; only topping up with distilled water on serviceable batteries is allowed.
Other terms
- Airbag Warning Light (SRS Light)
- Blower Resistor (Fan Speed Resistor)
- Charge Point Operator (CPO)
- CVT (Continuously Variable Transmission)
- Dual-clutch Transmission (DCT)
- Ignition Advance
- Injector Coding
- Leak-down Test (Cylinder Leakage Test)
- Octane Rating
- Oil Analysis
- Oil Pressure
- Receiver-drier (A/C Drier)
- Reverse Gear
- Sunroof Drain
- Two-Stroke Engine
- Underbody Protection
- Valet Mode
- Wasted Spark Ignition
- Wheel Cylinder
- Wiper Blade