Group 100 Vs Group 78 Battery: The Complete Comparison

Knowing the exact BCI group battery size helps to find new battery replacements, but it’s often not enough as batteries also differ in other factors. Such as purpose, cell type, chemistry, and so much more.

The same can be said for a group 100 battery and a group 78 battery. So, what makes these two groups different?

The most obvious difference that can be seen between these two batteries is their varying dimensions. However, they also vary in weight, electrical capacities, chemistry, and so much more.

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Everything you need to know about the variations between a group 100 vs group 78 battery, will be covered throughout this article below.

Group 100 Vs Group 78 Battery: Quick Comparison Table

There are several key differences between a group 100 battery and a group 78 battery.

Group 100 Vs Group 78 Battery

DifferencesGroup 100 BatteryGroup 78 Battery
Dimensions (Inches) (L x W x H)10.25 x 7.0625 x 7.37510.25 x 7.0625 x 7.3125
WeightSlightly HeavierSlightly Lighter
CCA Range (Cold Cranking Amps)750 – 800465 – 875
Best Used forUsed when excess current is needed. It is possible to increase current capacity and reduce charging time.One of the most common batteries used in cars, trucks, and the light industry.
Similar Battery GroupsGroup 78 Batteries Group 85 Batteries Group 101 BatteriesGroup 25 Batteries Group 86 Batteries
Cost$90 – $120$100 – $180
Durability (Years)6 – 103 – 10

What Are the Differences Between a Group 100 Vs Group 78 Battery?

The table in the above segment shows the key differences between a group 100 battery and a group 78 battery.

However, for further explanation, I will brief on these features below.


The dimensions of both of these batteries can be seen in the chart provided above. It should be clear to you now that a group 100 battery is almost similar to a group 78 battery.

The difference lies in the height of both these batteries. A group 100 battery is slightly taller than a group 78 battery.

When it comes to measurements, you must select the one that is appropriate for your car. That is the only issue you should be concerned about when it comes to battery size.


A group 78-sized battery normally weighs more or less around 25 kilograms. In terms of pounds, they weigh between 45 and 55 pounds.

On the other hand, a group 78-sized battery normally weighs around 22 kilograms. In terms of pounds, they weigh between 38 and 51 pounds.

So, if weight is an aspect you wish to focus on, a group 78 battery should be your optimal choice. However, batteries vary in weight based on brand and model, be sure to check properly before you buy.

CCA Range (Cold Cranking Amps)

Group 100 batteries tend to have a higher average rating for cold-cranking amps. Clocking in at around 750 to 800 amps on average.

However, the average CCA range is around 465 to 875 for group 78 batteries, but some may exceed that.

So technically, a group 100 battery will provide you with better power in colder weather than a group 78 battery. Because it has a higher average CCA range.

Best Used for

If you need to increase current capacity and reduce charging time, connect batteries in parallel. If you have two 12V lead-acid batteries with 60 Ah capacity and you connect them in parallel, you’ll get 12 Volts with 120 Ah.

BCI group 78 batteries are frequently used in ‘Stop-and-Go’ automobile applications, which need the batteries to deliver huge currents frequently and be recharged fast.

Now it is up to you which aspect is more important to you and is required by your system.

Similar Battery Groups

The physical dimensions of a group 100 battery are very similar to several other battery groups, allowing these batteries to be used almost interchangeably. Which are group 78, group 85, and group 100 batteries.

On the other hand, group 25 and group 86 batteries tend to be similar and interchangeable with group 78 batteries.


Group 100 batteries tend to cost significantly less than group 78 batteries. They only cost around $110 on average.

But a group 78 battery price can range between $100 and $180. Which is a huge price range.

So, group 100 batteries tend to be more budget-friendly.


Group 100 batteries tend to have higher average battery life and durability than group 78 batteries. Averaging at around 8 years.

Whereas a group 78 battery has average durability of 6/7 years.

That being said, it depends on the weather and the magnitude of user use. If maintained properly, they may both serve you for a long while.

Group 100 or Group 78: Which One Should You Choose, Finally?

Sincere to say, a lot of it depends on the users’ preferences and the size of the battery compartment of the car. I will brief more on the subject below.

If your battery compartment has enough space for a battery of either group size, you can choose any of them if they seem to match the electrical requirements of your vehicle.

However, if you can accommodate space for both, you might want to consider another feature. If you live in a colder region with harsh weather, you may want to opt for a battery with a higher CCA (cold cranking amps) rating. As it will help you start your car effortlessly.

But if not, you may wish to opt for a group 78 battery. As these are pretty easy to find. Unlike a group 100 battery which tends to be quite rare.

My Recommended Group 100 and Group 78 Batteries

As a buyer, you may feel overwhelmed with which battery to choose from, as there is a huge list of available batteries. So, I’ll provide you with a suggestion.

Group 100 Batteries

EverStart Maxx Lead Acid Automotive Battery

– Has a cold cranking amp (CCA) of 770.

– Company provides a 3-year free replacement warranty.

XS Power D3400 Battery

– 3-year warranty provided by the company.

– Ultra-low internal resistance, mounts in almost any position

Group 78 Batteries:

ACDelco 78AGM

– Enhanced life alloy increases cycle life and improves performance.

– Vent cap design that resists acid leakage.

Delphi BU9078 MaxStart

– Superior corrosion resistance sealed housing.

– 20x the vibration resistance of conventional batteries.

Odyssey 78 PC1500

– Recharges faster than other competitors.

– Extremely vibration resistance and high mounting flexibility.

Frequently Asked Questions (FAQs):

u003cstrongu003eWhat type of replacement battery should I buy?u003c/strongu003e

Buy wet cell battery, or an AGM battery. The CCA rating of the new battery should be the same or higher than your old battery.

u003cstrongu003eHow long should a car battery last?u003c/strongu003e

Four to five years and can be as short as three years in hot climates. AGM batteries usually last up to 6 years or longer.

u003cstrongu003eHow can I know the size of a battery?u003c/strongu003e

You can simply measure the length, width, and height of the battery. And then match it to a chart and easily find the corresponding battery group.


Throughout this article, I have discussed the differences between group 100 vs group 78 battery, so that you’ll be able to take a proper decision on which battery size to choose.

Before purchasing a replacement, it’s crucial to consider the battery group. You might lose a lot of money by making poor judgment calls. Therefore, understanding the differences between various battery sizes is essential.

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