H7 vs H8 Battery: Size, Capacity, CCA and the Upgrade Question
H7 and H8 are the two large European (EN/DIN) passenger-car groups — the batteries of big sedans, SUVs and luxury cars. They share width and height; the entire difference is ~37 mm of length, which buys the H8 roughly 20 Ah more capacity and 100–150 A more CCA.
Side-by-side comparison
| H7 (L4 / LN4) | H8 (L5 / LB5) | |
|---|---|---|
| Standard | EN/DIN | EN/DIN |
| Dimensions | ~315 × 175 × 190 mm | ~352 × 175 × 190 mm |
| Capacity (typical) | ~70–80 Ah (20h) | ~90–95 Ah (20h) |
| CCA (typical) | ~760 A (EN 50342) | ~850–900 A (EN 50342) |
| Terminals | SAE post | SAE post |
| Typical vehicles | Large sedans, mid SUVs | Large SUVs, luxury, light trucks |
Cross-verified typical ranges from the World Battery Hub data section; a specific battery's datasheet wins. CCA figures are EN 50342 (−18°C) — compare only within one standard (see what CCA is). For the full three-way picture with H6, see H6 vs H7 vs H8.
The physical difference: ~37 mm of length
Both groups share the ~175 mm width and ~190 mm height of the EN/DIN large-car family, with SAE posts in the standard positions. The only dimensional change is length: the H8 is roughly 37 mm (about 1.5 inches) longer. That extra room holds larger plates, and the larger plates are the entire source of the H8's higher Ah and CCA.
The fit rule follows directly: an H8 drops into an H7 tray only if ~37 mm of length is spare. Many vehicles are offered with both groups from the factory — same tray, different hold-down position — but plenty are not, so the tray, not the catalogue, is the authority. The battery size selection guide covers measuring the tray properly.
AGM, EFB and the start-stop question
H7 and H8 vehicles are disproportionately start-stop models, and start-stop changes the purchase completely: the car needs the technology it was designed for — usually AGM, sometimes EFB — not a plain flooded battery. Fitting a standard flooded unit into a start-stop car shortens its life sharply and can disable the system.
The second start-stop rule is registration: many modern cars track battery age and charge history in the battery management system, and a new battery must be registered electronically so the car resets its charging strategy. This applies whether the replacement is the same group or an upgrade, and it is a workshop step, not an optional extra. See the start-stop battery guide for the full picture.
Is the H7 → H8 upgrade worth it?
- Fits, same technology, more reserve — a genuine upgrade: more Ah for accessory load and longer parking endurance, more CCA for cold starts.
- Does not fit — the question ends; an H8 in an H7 tray is a safety hazard, not an upgrade.
- Start-stop vehicle — upgrade only within the maker-approved technology (AGM→AGM, EFB→EFB) and register the battery.
- Downgrade H8 → H7 — fits physically but drops capacity and CCA; re-check the vehicle's electrical load first.
Key takeaways
- H7 and H8 differ in length only — ~315 mm vs ~352 mm, same width and height.
- The extra length buys ~20 Ah and ~100–150 CCA (typical): a real but modest upgrade.
- Tray fit decides the upgrade; output decides only whether it is worth doing.
- On start-stop cars, match the technology (AGM/EFB) and register the battery — this matters more than the group size.
What procurement buyers should check
- Is the group decision locked to the vehicle's actual tray and hold-down, not to a catalogue equivalence table?
- Are the quoted Ah and CCA figures tied to a discharge rate and a named standard (EN 50342 vs SAE vs DIN)?
- For start-stop fleets: is the technology (AGM / EFB) specified, and is battery registration part of the installation procedure?
- Is the terminal layout and polarity verified — including position, which varies across DIN/EN variants?
- Do quotations across suppliers compare like for like — same group, same technology, same CCA standard?
Frequently asked questions
What is the difference between H7 and H8 batteries?
Length and output. Both are EN/DIN 12V groups about 175 mm wide and 190 mm tall, but H8 is roughly 37 mm longer — about 352 mm versus about 315 mm for H7 — and typically carries about 90–95 Ah and 850–900 CCA (EN) versus about 70–80 Ah and 760 CCA for H7.
Can I replace an H7 with an H8?
Only if the tray, hold-down and cables accept the ~37 mm longer H8 case. The electrical upgrade is real — more capacity and CCA — but the physical fit decides, and on start-stop vehicles the battery management registration requirement also applies.
Do H7 and H8 batteries need AGM or EFB?
If the vehicle has start-stop, yes — it needs the battery technology it was designed for, usually AGM or EFB, and many cars require electronic registration of the new battery. Replacing with a plain flooded battery in a start-stop car shortens life and disables features.
What is the H7 equivalent in North America?
H7 is commonly cross-referenced as BCI Group 94R (L4/LN4); H8 is commonly cross-referenced as BCI Group 49 (L5). These are close physical equivalents, not universal interchangeability rules — verify dimensions, terminals, hold-down and polarity before substituting.
Sources
Cross-verified from the World Battery Hub entity database and public references; where sources differ, the difference is flagged rather than silently resolved.
- World Battery Hub data section — H7 reference page and H8 reference page.
- EN 50342 — European lead-acid starter battery standard used for the quoted CCA figures.
- Manufacturer datasheets (AGM and EFB, H7 and H8) — dimension, capacity and CCA cross-checks.
- Vehicle OEM battery specifications — group and technology requirements for start-stop models.
Last reviewed: 2026-09-22