Technical insight

Battery Group Size Matching for Sodium-Ion Starter Batteries

Match LN, L, BCI, B and D battery case references to sodium-ion candidates, then verify dimensions, terminals, hold-downs, CCA and vehicle charging.

NaVolt Editorial Team 7 min read

Battery group size matching is a fast way to shortlist a replacement, but it is not installation approval. LN, L, T, BCI, B and D references can point a catalogue team toward the correct case family. The final choice still depends on the exact battery dimensions, hold-down, polarity, terminal design, CCA, voltage and charging system.

This distinction is essential when moving from conventional automotive posts to a sodium-ion battery with an M6 bolt interface.

What a group-size reference can tell you

Battery Council International describes group size as a system for standardizing dimensions, terminal location and related performance or fitment characteristics. BCI also publishes dimensional and assembly references for vehicle batteries.

A group-size name can help identify:

  • the general case envelope;
  • terminal position and polarity convention;
  • hold-down or assembly features;
  • a reference performance range;
  • catalogue cross-references.

It cannot confirm that every regional vehicle variant has the same tray, cable, bonnet clearance, battery sensor or charge profile.

Keep three records separate

Record Purpose Example
Current product specification Controls the battery being supplied H5: 245 × 175 × 190 mm, 40 Ah ±5%, 850 A CCA
Case-class cross-reference Helps shortlist equivalent market names LN2, L2, T5, Group 47 candidate class
Vehicle approval record Documents the exact installation tested Vehicle year, engine, market, terminals, charge data

Do not overwrite the current product dimensions with a dimension found in a catalogue or the vehicle-fitment table. They answer different questions.

NaVolt’s current controlled vehicle-fitment table is useful for candidate selection, but the current production sample still needs confirmation in the target vehicle. Product dimensions and fitment-reference dimensions are shown in separate columns below so neither record overwrites the other.

Model Product dimensions (W × D × H) Fitment-table reference dimensions 25°C CCA Cold-start CCA Cross-references Example applications in current table
H4-12V-400 207 × 175 × 190 mm 207 × 175 × 190 mm 660 A 560–750 A LN1, L1, T5, Group 47 Volkswagen Golf; Peugeot; Renault; Fiat; other A0/A-class cars
H5-12V-500 245 × 175 × 190 mm 247 × 175 × 191 mm 850 A 650–850 A LN2, L2, T5, Group 47 Volkswagen Golf, Sagitar/Jetta, Passat and Lavida; Audi A3/Q3; BMW 3 Series; Ford Focus
H6-12V-600 281 × 175 × 190 mm 278 × 175 × 192 mm 1,000 A 730–950 A LN3, L3, T6, Group 48 BMW 3/5 Series and X5; Audi A4/A6/Q5; Volvo XC90; Honda Avancier; Volkswagen Tiguan
H7-12V-750 315 × 175 × 190 mm 315 × 175 × 193 mm 1,200 A 850–950 A LN4, L4, T6, Group 94R Mercedes-Benz C/E/S-Class; BMW 5/7 Series; Audi A6/A8/Q7; Porsche Cayenne
H8-12V-840 354 × 175 × 190 mm 354 × 175 × 194 mm 1,400 A 900–950 A LN5, L5, T6, Group 49 BMW 7 Series/X5/X6; Mercedes-Benz GLS/G-Class; Audi Q7/A8; Range Rover; Porsche Panamera
H9-12V-900 410 × 175 × 190 mm 394 × 175 × 195 mm 1,600 A 950–1,100 A LN6, L6, T7, Group 95R Mercedes-Maybach S-Class; BMW 7/8 Series and X7; Audi A8; long-wheelbase Range Rover; large luxury SUVs

Several product dimensions differ from the fitment-table reference dimensions. H9 has the largest difference: 410 × 175 × 190 mm in the current product specification versus 394 × 175 × 195 mm in the fitment table. Treat the cross-reference as a search key and inspect the actual tray; do not merge the two records.

Model Product dimensions (W × D × H) Fitment-table reference dimensions 25°C CCA Cold-start CCA Cross-references Example applications in current table
B19-12V-500 192 × 128 × 222 mm 187 × 129 × 225 mm 500 A 360–420 A B19 Nissan Note/March; Suzuki Alto/Swift; Daihatsu; kei and microcars
B24-12V-660 238 × 130 × 222 mm 238 × 129 × 225 mm 660 A 450–480 A 55B24 L/R, T5, H4, Group 26 Honda Fit/Civic/CR-V; Nissan Tiida/Sylphy; Mazda3/Axela
D23-12V-850 231 × 175 × 222 mm 232 × 173 × 225 mm 850 A 500–560 A 55D23 L/R, 75D23, Group 35 Toyota Corolla/Camry/RAV4; Honda Accord/Odyssey; Nissan X-Trail/Teana; Mazda CX-5
D26-12V-850 261 × 173 × 223 mm 260 × 173 × 225 mm 850 A 600–680 A 55D26 L/R, 80D26, 95D26, Group 34 Toyota Highlander/Land Cruiser Prado; Honda Elysion/UR-V; Nissan Patrol; Infiniti Q50/Q50L
D31-12V-1000 306 × 173 × 222 mm 306 × 173 × 225 mm 1,000 A 700–850 A 95D31 L/R, 115D31 Toyota Land Cruiser/Tundra/Sequoia; Nissan Patrol; Isuzu D-Max; large SUVs, pickups and commercial vehicles

The L/R notation makes polarity especially important. Define the viewing direction in the catalogue and use a photograph or terminal drawing. “Left positive” is ambiguous if two teams view the battery from opposite sides.

The M6 terminal is a separate fitment decision

All current NaVolt 12 V specifications list positive and negative terminals with an M6 bolt-type interface. This field does not prove compatibility with SAE, DIN or JIS tapered posts.

A connection approval should record:

  • lug or adapter part number;
  • conductor size and current capacity;
  • contact surface and plating;
  • tightening torque;
  • insulation and terminal cover;
  • cable reach and bend radius;
  • tool clearance and short-circuit protection.

Do not hide an unvalidated adapter inside a group-size equivalence claim.

Electrical matching follows physical matching

Once the case and terminals are workable, compare nominal voltage, CCA, capacity, continuous-current limits and charging. Current NaVolt 12 V specifications list a 15.8 V charge voltage and 6 V discharge cut-off. The vehicle profile must be reviewed against the battery requirement.

CCA should be compared using the same standard. SAE J537 is one recognized automotive storage-battery test reference. The current fitment table labels separate 25°C CCA and cold-start CCA fields; those fields must remain identified by their stated conditions and must not silently overwrite a product-specification CCA field.

A catalogue approval workflow

Stage 1: Desk match

Use original-battery dimensions, voltage, CCA and group references to create a candidate list.

Stage 2: Sample inspection

Place the current production sample in the tray without connecting it. Verify hold-down engagement, lid clearance, polarity and cable reach.

Stage 3: Connection approval

Approve the terminal solution, torque, insulation and voltage drop under crank.

Stage 4: Vehicle test

Check starting, repeated start-stop, charging, battery sensor, registration, sleep current and diagnostic faults.

Stage 5: Catalogue release

Tie the listing to exact vehicle year, engine, market and installation notes. Keep photographs and test records available for warranty review.

Data fields for a fitment database

  1. Product model and revision
  2. Normalized L × W × H plus source dimension order
  3. Case-class references
  4. Terminal type, polarity and orientation photograph
  5. Hold-down and enclosure type
  6. Vehicle make, model, year, engine and market
  7. Original battery model, chemistry, Ah and CCA
  8. Charging and registration information
  9. Adapter or cable part number
  10. Approval status and reviewer

This structure prevents a group-size label from becoming the only evidence behind a warranty-sensitive listing.

Frequently asked questions

Is the same battery group size always interchangeable?

No. It is a strong shortlist signal, but case tolerances, terminals, polarity, hold-downs, cable routing and vehicle electrical requirements can differ. Inspect the exact installation.

Can a Group 47 battery and an LN2 battery be treated as identical?

They may appear together in cross-reference systems, but use the actual dimensional and assembly data from the applicable standard or catalogue. Then compare the current product drawing and vehicle.

Why does the product specification differ from a fitment table?

The product specification controls the manufactured battery. The current fitment table records reference dimensions, CCA fields, cross-reference names and example vehicle applications. Keep both records with clear labels instead of forcing them into one field.

Does matching dimensions prove electrical compatibility?

No. Voltage, CCA, charging, continuous-current limits, battery sensors and start-stop controls still need approval.

Conclusion

Battery group size matching gets a buyer to the candidate list. The product specification, terminal design and vehicle test decide whether the candidate can become an approved replacement.

Compare NaVolt starter and start-stop models or request a model and vehicle fitment review.

Sources