Corvette battery size and location, C4 to C8

Locations are from GM’s owner’s manuals; sizes are GM’s or owner-reported, as marked.

Group size is the industry code for case size and post layout. CCA (cold cranking amps) is rated starting current in the cold. AGM (absorbent glass mat) is a sealed, spill-proof alternative to the conventional flooded battery, and it needs its own charger setting.

The C4’s battery sits at the back of the engine bay on the driver side, beside the brake and clutch fluid reservoirs (1996 manual). GM’s 1994 and 1996 manuals list a Delco 75B-72 (OEM), and the 1994 manual adds a 75Z-72 (OEM) for the ZR-1. Owners call Group 75 correct; for 1984–1993 that’s owner-reported, since GM’s online manuals don’t list a battery for those years.

Of course, some owners go bigger. A Group 78 is about an inch longer: one owner trimmed the tray’s inboard lip, another cut both lips, and a 1993 owner says his fit tight without trimming. Stick with the 75 unless you’re ready to take a cutter to the tray.

The cables bolt into the side of the case, and one C4 owner warns not to over-tighten them. The easy way out is sideways, through the slotted lower fender panel behind the front wheel: Torx screws in the wheel well, a 10 mm bolt on top, loosen the 10 mm at the bottom. Reset the door gap when the panel goes back on. The C4 buyer’s guide covers the rest of the car.

The C5’s battery sits at the rear of the engine bay on the passenger side, close to the windshield. GM lists a Delco 78A-72H (OEM) for 1997 through 2000, a side-terminal Group 78 by owner accounts, then an ACDelco 75P-7YR (OEM, Group 75) for 2001. The 2002–2004 manuals list no battery. One owner recalls a Group 75 for 2002–2003 and a top-post Group 86 for 2004, but hedges, so on those years the label decides.

The C5-specific worry is underneath: the PCM (powertrain control module, the engine computer) sits below the tray. Owners have told NHTSA of batteries leaking acid onto the PCM and wiring below (opens in new tab), and owners on the forums call it a common reason to go AGM. If the old battery is crusty, look under the tray.

A weak battery also upsets the electronic column lock. GM’s recall 04V060000 (opens in new tab) says low voltage at the PCM can defeat the fuel cut-off that stops the car moving with the steering locked, and 2001 owners’ complaints to NHTSA tie column lock trouble to a weak battery. The C5 buyer’s guide and C5 years to avoid cover the rest.

Base C6s keep the battery where the C5 had it, beside the fuse block with the cabin air filter next to it. The Z06, ZR1, manual Grand Sport coupe and 427 Convertible have a dry-sump engine (the oil lives in a separate tank), and on those cars the battery is in the rear (2013 manual). Owners describe a tight compartment under the carpet where a Group 48 is too tall, so measure first. The C6 buyer’s guide explains the models.

Size is the least settled of any generation, so here is the record:

• 2005: Group 86, per a GM-certified technician on Corvette Action Center and owners on CorvetteForum.
• 2006–2007: mostly reported as Group 90, also sold as T5.
• 2008–2013: split. A 2008 bought new came with an ACDelco 85G, and a 2012 owner says a Group 90 wouldn’t lock under the tray’s rear lip, while a 2011 Grand Sport owner in the same thread runs a Group 90 that he says fits perfectly.

GM’s 2013 warranty table (bulletin 15-06-03-002) names an ACDelco 48PS as that year’s replacement, but owners say a Group 48 fits the tray and blocks the cabin air filter door. The terminal layout changed after 2005, so match the posts, not just the case. 2012–2013 cars left the factory with a flooded, 590 CCA battery (GM bulletin PI1098A).

Every C7 carries the battery in back, in the hatch area on the passenger side, under the carpet and a battery cover. GM bulletin 15-06-03-002 and its 2018 revision list the 2014–2018 original as part 22940819 (OEM), flooded, 615 CCA (opens in new tab), with an ACDelco 48PS (OEM, GM 88865244) as the replacement. GM’s table stops at 2018; a 2019 Z06 owner replacing his factory battery shopped for a Group 48, and owners say any Group 48 (H6) fits.

Two owner tips: the terminals take a 12 mm socket, and the original battery has no handles, so bring a lifting strap. The C7 buyer’s guide covers the rest of the car.

When the engine moved behind the seats, the battery went to the other end of the car. It sits under a cover and side shields in the front compartment (opens in new tab): remove the right and left sight shields, then the second cover. Positive is on the driver side, negative on the passenger side. The 2025 manual shows the same for the Stingray, Z06 and E-Ray; it doesn’t cover the ZR1, so check a ZR1’s own manual. Owners use a trim tool and a 10 mm socket.

GM’s owner’s manuals give no group size. Owners report the non-hybrid cars left the factory with a flooded battery, not AGM: an ACDelco 48PG in one account, and GM 88866309, which another owner found listed on GM’s parts site for a 2022. Both are Group 48 (H6). One owner lists the 2020–2021 original at 730 CCA. All owner-reported: check your label.

The E-Ray uses a lithium 12-volt battery

The E-Ray’s 12-volt battery is lithium-ion, used only in the E-Ray (opens in new tab). It needs a higher voltage than lead-acid to jump, and GM says jumper cables work only with some donor vehicles, so the 2025 manual adds a jump box procedure. GM’s dealer tester can’t test it, and dealers order replacements straight from the supplier.

Nothing takes the swagger out of a V8 like a slow, groaning crank on a cold morning.

• Slow crank or no crank, especially after sitting or in the cold. GM’s bulletin 15-06-03-001 says to warm a cold battery before testing it and never to charge a frozen one.
• Battery messages on the DIC (Driver Information Center, the gauge display): BATTERY SAVER ACTIVE and BATTERY VOLTAGE LOW on a C6; LOW BATTERY and SERVICE BATTERY CHARGING SYSTEM on a C7 (2013 and 2014 manuals). A C8 has a Battery Voltage info tile that shows the 12-volt reading.

If a new battery goes flat again, look for a drain before buying another one.

1. 2005 manual-transmission C6s shut off in the wrong gear. Unless the car is shifted into reverse before shutdown, the ignition stays on until it drains the battery (opens in new tab) (GM bulletin PIC3139C); the DIC shows SHIFT TO REVERSE as a reminder. From 2006 on, the reverse step isn’t needed. The 2005 is also where NHTSA’s battery complaints cluster: by this site’s count, 29 of the 54 C6 complaints that mention the battery are on 2005 cars, and a few owners say theirs went flat even after the reverse shutdown.
2. Modules that won’t go to sleep, 2009–2025. GM bulletins cover a parasitic drain (power draw with the car off) from the OnStar module on 2009–2010, 2011–2013, 2015 and 2017 cars; the memory seat module below 40 °F on 2018–2020; a radio that stays on after shutdown on 2021–2022; a drain after over-the-air software updates on 2023 and 2024–2025 cars; and the gateway module on 2024. If your year is listed, ask a dealer whether the fix was done.

Every row comes from the owner’s manuals, and so do the ground rules: a donor with a 12-volt, negative-ground system, accessories off, clamps on in the listed order and never touching, and eye protection. Be picky about boosters, because the wrong one gets expensive. GM found that non-approved chargers and boosters can damage headlamp bulbs and control modules (opens in new tab) on 2008–2016 GM vehicles, with some models seeing more than 20 volts during a jump, and it tells dealers that damage isn’t warranty work. After a jump or disconnect, a C6 to C8 may need its power windows re-indexed.

C6 and C7. GM’s advisory 15521: open the hatch with the key, then pull the manual door release in the trunk (opens in new tab) to open the driver door. From inside, use the manual release levers on the floor.

C8. Use the mechanical key in the backup lock hidden in the air inlet behind the driver door handle. Inside, pull the manual hood release loop to the left of the brake pedal twice to open the front trunk; the emergency release button inside the front compartment won’t work with a dead battery (2020 and 2025 manuals). 2020–2022 cars also have a trunk key lock behind the rear license plate, deleted for 2023 (GM bulletin PIC6502B).

A C8 with no 12-volt power can’t release its electric parking brake or shift to Neutral, the 2025 manual says, so it goes onto a flatbed on tire skates or dollies.

• C4 to C6 without a maintainer: GM’s 1996, 2004 and 2005 manuals say to remove the negative cable if the car will sit 25 days or more.
• Late C6 and C7: for long storage, the manuals call for a maintainer or trickle charger or pulling the negative cable; on a C7, plug the maintainer into the rear accessory outlet only.
• C8: the underhood outlet only, which is powered at all times. The E-Ray needs a GM-approved lithium charger.
• Any AGM battery: use a charger with an AGM setting. GM notes in bulletin 23-NA-044 that AGMs charge about 2 volts lower than flooded batteries, can freeze below about 50% charge, and are permanently damaged by long storage at low charge.

GM’s battery bulletin 15-06-03-001 says to charge a stored battery every 30 days to keep it above 80%, because below that, sulfation (lead sulfate building up on the plates) can start in as little as two weeks. A Corvette that sits for weeks belongs on a maintainer, so the first warm Saturday starts with a V8, not a jump. The battery maintainer guide covers which one to buy and where to plug it in on each generation.

Difficulty is this site’s rating from the owner accounts in each generation’s section. Time: the CorvetteForum how-to calls a C5 to C7 swap a few minutes’ work, and a C6 owner puts a 2005 at about 10 minutes. A C4 owner does it through the fender panel in under 20 minutes; a dealer that went in from the top billed him 1.5 hours. No source gives a C8 time. Cost: owners in a July 2026 CorvetteForum thread quoted about $150 to $210 for a Group 48 (C7 and C8), from a sale-priced AGM at a big-box store to the dealer’s original part. This guide has no dated price for older sizes.

Flooded or AGM: matching the factory type is always safe. But of course you want more, and AGM is a reasonable upgrade: GM calls AGMs spill-proof, and with a C5’s computer under the tray, that’s a real reason to switch. Some owners keep the original type because the charging system is set up for it; go AGM and every charger you use needs an AGM setting. After the swap on a C6, C7 or C8, re-index the windows.

Here’s the call: read the label, match the size and the posts, and put a maintainer on any Corvette that sits. That way America’s sports car saves all its drama for the road.