Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Battery (All): Terminology: Capacity
The capacity is the ability of a fully charged battery to provide a constant current over a certain time and is given in ampere-hours (Ah). The time taken to discharge depends on the intended use of the battery. For starter batteries one refers to 20 hours capacity (K20). This refers to the amount of current the battery can provide over 20 hours at an ambient temperature of +25°C (+77°F) without the pole voltage falling below 10.5 V.
Example: A battery with a listed capacity of 70 Ah should be able to provide a current of a maximum 3.5 A (3.5A x 20h = 70 Ah) for 20 hours.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.