Group 78 battery size

Close in size

Groups within 10 mm (0.4 in) on every side:

• Group 58: 10.04 x 7.20 x 6.97 in, top posts instead of side terminals.
• Group 58R: 10.04 x 7.20 x 6.97 in, top posts instead of side terminals.
• Group 97R: 9.92 x 6.89 x 7.48 in, top posts instead of side terminals.

Before you buy a group 78 battery

• Read the group number on the label of the battery in your car, or in the owner's manual: it should say 78.
• A group with an "R" after the number has its terminals reversed: do not swap one for the other without checking where your cables reach.
• Choose cold cranking amps (CCA) at least as high as the original, especially for cold winters.
• Measure your battery tray and the room above it, then compare with the size printed for the exact battery you pick, not only with the group number.
• Group 78 has side terminals (threaded studs on the front): the new battery must match, and the hold-down must fit the box.
• Most stores take the old battery back for recycling, often against a core charge.

Good to know about group 78

• Group 78 has side terminals. Seen from the terminal side, the positive terminal is on the left.^1,2,3
• A dual-terminal 34/78 battery puts group 34-style top posts and group 78-style side terminals on one case.^1,4,5
• Group 78 and the dual-terminal 34/78 are common in many GM vehicles.^1,6,7
• Group 78 batteries are made in flooded and AGM versions.^1,2
• Real group 78 batteries can be longer than the 10.24 in BCI figure: NAPA, Batteries Plus and East Penn list 10.75 in, and Odyssey 10.8 in for its AGM, while AutoZone's size chart gives 10.25 in. Measure your tray before you buy.^8,9,10,11,12

How we checked this page

Checked on October 16, 2026. We kept a fact only when two independent sources agree, and each one is numbered to its sources below. We never write a price: the listings come straight from eBay and show what sellers ask. This page was written with an AI assistant and checked against the sources below.