Why has the battery in my car failed after just three years?

What type of stop/start battery is fitted to my Mercedes B-Class and why has it failed? The car is less than three years old and the mileage is 28000.

Asked on 26 November 2019 by Allan Monk

Answered by Honest John
It will be an 020 Bosch AGM Stop Start Battery S5A15, costing around £230. The usual reason for failure is not driving the car far enough often enough, though, as you rightly suggest, 28,000 miles in three years should have been enough to keep the battery fully charged and at full capacity.
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