Why positive terminal of battery is larger than negative terminal?

Answer 1

As a battery terminal seller, I measured all the battery terminal ends, it is different.

the size of positive and negative is a little different about 0. 1–0.3cm. maybe it does not want you to use it to the wrong battery post.

so more details, you can check the website Cohomer dot com.

the battery capacity is different, so the battery terminal is different. considering the electric current, and bear the corrosion and other things. So they aren’t usually common in size. The negative pillar is slightly smaller than the positive one.

Automotive batteries typically have one of three types of terminals.

In recent years, the most common design was the SAE Post, consisting of two lead posts in the shape of truncated cones, positioned on the top of the battery, with slightly different diameters to ensure correct electrical polarity.

The "JIS" type is similar to the SAE but smaller, once again positive is larger than negative but both are smaller than their SAE counterparts. Most older Japanese cars were fitted with JIS terminals.

General Motors, and other automobile manufacturers, have also begun using side-post battery terminals, which consist of two recessed female 3/8" threads (SAE 3/8-16) into which bolts or various battery terminal adapters are to be attached. These side posts are of the same size and do not prevent incorrect polarity connections.

L terminals consist of an L-shaped post with a bolt hole through the vertical side. These are used on some European cars, motorcycles, lawn and garden devices, snowmobiles, and other light-duty vehicles.

Some battery sizes are available with terminals in two different configurations: 1) positive on the left and negative on right, 2) negative on the left, and positive on right. Purchasing the wrong configuration may prevent battery cables from reaching the battery terminals.