You don't want sparks near the terminals of a bad battery, it can cause a small explosion that showers you in battery acid. https://en.wikipedia.org/wiki/Lead%

You don't want sparks near the terminals of a bad battery, it can cause a small explosion that showers you in battery acid. https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery#Risk_of_explosion https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery#Risk...