Terminals
Terminals, cables, and clean connections
How corrosion forms, what loose clamps feel like from the driver seat, and the difference between a charging fault and a contact problem.
5 min read
Corrosion is a symptom
The powder around a post is the product of vented gas reacting with metal. A little is normal on an older battery. A lot, especially on one post only, usually points at a poor seal, chronic overcharging, or a clamp that has never been fully tight.
A loose clamp behaves like a failing battery
Intermittent no-starts, a click with no crank, or accessories that reset while driving often trace back to contact resistance rather than a battery that has lost capacity. A clamp you can twist by hand is loose even if it looks seated.
Order of operations
Disconnect negative first and reconnect it last. Keep tools away from bridging a post to bodywork. If a clamp has spread or a cable end is soft and swollen under the insulation, replacing the end is part of the repair.