H6 vs. H7 vs. H8 Battery: Which group H battery should you fit into your car?

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When you are looking for a replacement battery for your car, it’s important to choose the right size. Luckily, battery manufacturers have agreed on standard sizes, which makes things easier. All you need to know is which battery size fits your car.

Of course, some batteries, such as the H6, H7, and H8, are similar in width and height. This means that you may be able to fit a more powerful battery, depending on the size of your battery tray. This brief article looks at the differences between the H6, H7, and H8 battery types.

What is the difference between H6, H7, and H8 batteries?

There are several differences between the H6, H7, and H8 batteries. The most obvious is the size, but the power, Cold Cranking Amps (CCA), Reserve Capacity (RC), and price vary, among other features.

It would be incorrect to assume that a bigger battery means more power. When all batteries were using the same technology, yes, this was the case. But now, improved battery internals means size is not a good judge of the power.

Differences in physical size

The width and height of Group H batteries are identical, with just the length varying. The length is the dimension from left to right if you are looking at the battery label on the front.

That said, the difference in length is less than eight centimeters between the H6 and the H8. This means that depending on your battery tray size, you may be able to fit the next size up.

Whether it is worth choosing another battery size will depend on your requirements, and we discuss this next.

Maximum BCI Group Dimensions (mm)BCI GroupMaximum DIN Battery Dimensions (mm)DIN Codes
306x175x19248278x175x190H6, L3Get Price
315x175x19094R315x175x190H7, L4Get Price
381x175x19249354x175x190H8, L5Get Price
Note: Affiliate links (‘’Get Price’’ column) open in the new windows, feel free to click them for up-to-date prices and offers.

Differences in specs: Reserve Capacity & Cold Cranking Amps

The reserve capacity and cold-cranking amps are where you will find the actual differences between H6, H7, and H8 batteries.

Reserve Capacity (RC)

The RC is a measure of how long a battery can operate your essential services while not being charged by the alternator. The standard value is the number of minutes the battery can provide a constant 25 amps before dropping below the minimum voltage.

Cold Cranking Amps (CCA)

The CCA of a battery refers to a battery’s ability to start an engine in cold environments. It indicates the number of amps a battery can supply at 0 degrees Fahrenheit for 30 seconds.

Generally, the larger the battery, the better RC and CCA values will be. However, it’s not as simple as that. The quality of the internal components and the type of battery technology used will also play a part.

This also affects the price of the battery, as discussed below.

Differences in prices

Prices of all three different types vary for many reasons. The lowest-priced will be a basic H6, but a low specification H8 won’t be much more. A high quality, top specification H6 can be costly.

As the price increases, so does the quality of the internal components and the available power from the battery, which we discuss next. As with many things in life, you often get what you pay for.

Having said that, the H7 and H8 are more common than the smaller H6, and economy of scale can give a price benefit. You may find an H7 or H8 cheaper than the equivalent H6 but with more power by shopping around. Just make sure it will fit your battery tray.

Find purchasing options for Low-priced Group H Batteries below:

ACDelco H6 Battery

ACDelco H6 Battery

ACDelco H7 Battery

ACDelco H7 Battery

ACDelco H8 Battery

ACDelco H8 Battery

Are H6, H7, and H8 batteries interchangeable?

What does H6/H7/H8 battery fit?

Batteries in the H series are designed to fit modern cars and light commercial vehicles. You will find them fitted as standard equipment to most European cars and the majority of modern cars made in the USA.

Is it worth upgrading from H6 to Bigger Group Size?

A simple answer would be yes, but there’s more to it than that. Let’s look at what you should consider when contemplating fitting a larger group battery.

Size: Your vehicle manufacturer made the car’s battery tray to fit a particular dimension of battery. Of course, for economic reasons, a battery tray fitted to one model may also be used in another car model, and your’s may be larger than it needs to be. Measure your tray carefully before ordering a battery.

CCA: The rule here is to fit a battery with at least the same CCA as the OEM battery. If you can fit a battery with a higher CCA, particularly in colder climates, it will improve your cold starting.

Type of battery: Not all batteries are made the same! Batteries are designed for a particular purpose. A battery for starting your car may have a high CCA value but not a high RC value. A battery designed to run the electrics in your RV doesn’t need a high CCA value but a high RC value.

Terminal Position: Some batteries are sold with different terminal positions. If you choose a battery with the wrong terminal position, the cables may not stretch far enough to fit. Just as bad, you may overstretch the cables causing damage and charging issues.

Below are our recommendations for group H6, H7, and H8 batteries and their specifications & prices:

Group H6 Price RangeDimensions (in)CCARC
ACDelco 48AGM$175-$18511.9×7.5×7.6 760 120See More
Optima DH6$285-$29510.94×6.89×7.48 800 140See More
XS Power D4800$345-$35510.94×7.48×6.93 760 132See More
Group H7Price RangeDimensions (in)CCARC 
ACDelco 94RAGM$155-$17012.4×6.9×7.5 850 140See More
Delphi BU9094R$215-$23012.5×7.5×7 850 140See More
Group H8Price RangeDimensions (in)CCARC
ACDelco 49AGM$200-$21013.9×6.9×7.5900160See More
Delphi BU9049$290-$29513.9×7.5×6.9850170See More
Note: Affiliate links open in the new windows, feel free to click them for up-to-date prices and offers.


Choosing the correct battery for your car isn’t difficult. Make sure you select the right size with the correct CCA and RC ratings, and you’ll be fine.

If you want to upgrade your battery, perhaps to increase the CCA value, you need to make sure the non-standard battery will fit. Hopefully, our short guide has given you the confidence to upgrade your H series battery.

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