Battery Equivalents and Replacements

How Many Ah is a Car Battery?

Car batteries differ in size, capacity, BCI group, type, and a few more details, just as cars differ in size, type of engine, engine size, and similar.

The capacity of the car battery is given in Ah (Amp-hours) and mostly varies between 35Ah and 100Ah, although there are even smaller, but also larger batteries or battery packs used in modern cars.

Published: March 23, 2023.

ah car battery 1

Car Battery Features and Specifications

Car batteries are mostly starting lead-acid batteries, designed to provide strong currents for a very short period of time.

Such strong currents are required for cranking gas and diesel engines commonly used in modern passenger vehicles, smaller trucks, and similar.

Thus, car batteries can differ:

- battery type: most car batteries are starting batteries, although some vehicles also use dual-purpose batteries due to the large number of different loads that must be powered while the engine is turned off.

Some vehicles also use backup batteries to provide charge for the onboard electronics while the main battery is being replaced, or if it dies for some reason.

- battery chemistry: most car batteries are wet/flooded lead-acid batteries, although Gel-Cell and AGM batteries are becoming more and more common.

Lithium drop-in replacement batteries are slowly replacing lead-acid batteries in certain vehicles, offering some performance advantages due to the lightweight design.

- BCI battery groups: car batteries differ in size, terminal type, and orientation - most cars use ~10 typical BCI battery groups, although there are models that sometimes use somewhat specific and not so common battery sizes.

- Cold Cranking Amps (CCA) rating is given in Amps and describes the car's ability to provide strong currents. The battery's capacity is not always directly related to the CCA rating, since the CCA value depends on other details, for example, if the battery is starting or dual-purpose or even deep-cycle battery.

Of course, car batteries differ in many other ways, but these are the most important ones.

ah car battery 2

BCI Battery Groups and the Battery Capacity (Ah)

The following list shows the capacity (Ah) of starting and dual-purpose car batteries according to the battery BCI group:

- BCI Group 24 Batteries: 75-85 Ah,

- BCI Group 34/78 Batteries: 55-68 Ah,

- BCI Group 35 Batteries: 40-65 Ah,

- BCI Group 47 (H5, L2, 55L2) Batteries: 50-60 Ah,

- BCI Group 48 (H6, L3, 66L3) Batteries: 60-75 Ah,

- BCI Group 49 (H8, L5, 88L5) Batteries: 80-95 Ah,

- BCI Group 51 and 51R Batteries: 38-60 Ah,

- BCI Group 65 Batteries: 70-75 Ah,

- BCI Group 75 Batteries: 44-60 Ah,

- BCI Group 94R Batteries: 75-80 Ah, etc.

Some battery groups have batteries that differ greatly in capacity due to the different battery's internal designs (for example, spiral wound plates vs flat plates), different battery types (starting vs dual-purpose), and chemistry (lead-acid vs lithium batteries).