Battery terminals — identifying post sizes On a typical automotive lead–acid battery with top posts made to SAE dimensions, how does the negative terminal post size compare to the positive post?

Introduction / Context:
Correct battery terminal identification prevents reverse polarity connections that can damage electronics. Post size differences are a deliberate safety and service feature on many batteries built to common standards.

Given Data / Assumptions:

• Top-post automotive lead–acid battery using SAE dimensions.
• Standard tapered lead posts with color or polarity markings.

Concept / Approach:
SAE top-post batteries typically use a larger diameter positive post and a smaller negative post. Mismatch prevents accidental swapping of cable clamps because the positive clamp will not fit properly on the smaller negative post and vice versa.

Step-by-Step Solution:
Identify that post diameters are intentionally different.Recall which is larger: positive is larger, therefore negative is smaller.Select the option stating the negative is smaller than the positive post.

Verification / Alternative check:
Visual inspection and calipers confirm the dimension difference; cable clamp sizes are also keyed to the polarity.

Why Other Options Are Wrong:
Stating the negative is larger or equal contradicts the standard. “None of these” is inapplicable because one option correctly identifies the size relationship.

Common Pitfalls:
Confusing Japanese Industrial Standard (JIS) batteries or side-terminal designs, which use different interfaces; always verify polarity markings in addition to size.

Final Answer:
smaller than the positive terminal post