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Group 51R Battery

Aliases: 51R · 51 (reversed terminal) · Standard family: BCI/SAE

Direct answer: The Group 51R battery is a BCI/SAE-family group — a 12V lead-acid case of 238 × 129 × 223 mm with SAE post (reversed polarity) terminals, typically 45–50 Ah and 450–500 cold cranking amps (SAE J537 (−18°C)).

Quick facts

Identification

Entity type	BatteryGroup
Group name	Group 51R
Aliases	51R / 51 (reversed terminal)
Standard family	BCI/SAE

Specification

Voltage	12V
Typical capacity	45–50 Ah
Typical CCA	450–500 A
Dimensions (L×W×H)	238 × 129 × 223 mm
Terminal	SAE post (reversed polarity)
Typical weight	13–15 kg

Standards & measurement context

Naming standard	BCI/SAE
CCA basis	SAE J537 (−18°C)

The CCA figure is defined by its test standard — values from different standards are not directly interchangeable. Capacity values are typical ranges, not a substitute for a specific battery's datasheet.

Applications

Honda compacts
Nissan compacts
Japanese imports

Technology variants

Flooded / EFB / AGM — see the lead-acid type family for the design trade-offs behind the label.

Equivalent capacity class

~45–55 Ah — other groups in a similar capacity class. This is a capacity comparison, not a physical interchange: dimensions and terminals differ between naming families.

Testing

Relevant methods for this group: CCA testing, capacity testing, load testing — see the testing methods for procedures and standards.

Sources & verification

CCA 450–500 A — SAE J537 (−18°C)

Evidence card — how this entity's data was established

Basis: BCI group dimension tables + manufacturer datasheets

BCI Battery Replacement Data Book (group dimensions)
Manufacturer datasheets (East Penn, Exide, Interstate, Odyssey)

Confidence: High · Last verified: 2026-09

Same case as Group 51 but with REVERSED terminal polarity. Dimensions match Group 51; the 'R' suffix denotes reversal. Not interchangeable with Group 51 without checking cable routing.

Last verified: 2026-09

Values are cross-verified typical ranges, not a substitute for a specific battery's datasheet. Return to World Battery Hub.