Which Battery Size Standard Is Right for Your Application?
Which Battery Size Standard Is Right for Your Application?
Battery Pack Size Standards Explained: BCI Group, DIN / EN, and SLA / VRLA
When selecting the right battery for an application, capacity and chemistry are only part of the equation. Battery size standards play a critical role in ensuring mechanical compatibility, safe installation, and reliable performance.
In this article, we introduce the three most common battery size standards used worldwide: BCI Group, DIN / EN, and SLA / VRLA. We will explain their typical uses and differences.
1. BCI Group Battery Sizes
BCI (Battery Council International) standards are widely used in North America, especially for automotive, commercial vehicle, and industrial batteries.
Key Features of BCI Group Standards
- Defined by physical dimensions, terminal location, and terminal type
- Each battery is assigned a Group Number (e.g. Group 24, Group 27, Group 31)
- Batteries within the same group share the same outer dimensions, regardless of brand
Typical Applications
- Passenger vehicles and trucks
- Commercial fleets and off-road vehicles
- Industrial and backup power systems
BCI standards make it easy to replace batteries. Users can choose a compatible group size without changing battery trays or mounting structures.
2. DIN / EN Battery Sizes
DIN (Deutsches Institut für Normung) and EN (European Norm) standards are commonly adopted in Europe and many international markets.
Key Features of DIN / EN Standards
- Battery sizes are specified by length, width, and height
- Frequently combined with performance indicators like capacity (Ah) and cold cranking amps (CCA).
- Typically feature recessed or flush terminals, improving safety and vibration resistance
Typical Applications
- European passenger cars and commercial vehicles
- Industrial equipment and energy storage systems
- OEM applications requiring compact and standardized footprints
People recognize DIN / EN batteries for their small size and high energy density. This makes them ideal for space-constrained installations.
3. SLA / VRLA Battery Sizes
SLA (Sealed Lead Acid) and VRLA (Valve-Regulated Lead Acid) batteries come in standard sizes. The industry recognizes these sizes. They do not follow specific automotive standards for different regions.
SLA and VRLA batteries are commonly available in absorbent glass mat (AGM) and Gel designs, offering maintenance-free operation. While people traditionally associate these formats with lead-acid systems, they increasingly use similar standardized dimensions for technologies like lithium-ion replacements.
Key Features of SLA / VRLA Sizes
- Maintenance-free, sealed construction
- Standardized case sizes (e.g. 12V 7Ah, 12V 9Ah, 12V 100Ah)
- Available in AGM o Gel designs
Typical Applications
- UPS systems and backup power
- Telecom and data centers
- Solar energy storage and emergency lighting
Because of their standardized case dimensions, SLA / VRLA batteries are widely compatible across brands and systems.
Comparison of Common Battery Size Standards
| Standard | Primary Region | Typical Use | Size Definition |
|---|---|---|---|
| BCI Group | North America | Automotive, industrial | Group number |
| DIN / EN |
Europe | Automotive, OEM, industrial | Dimensional code |
| SLA / VRLA | Global | Backup energy storage |
Case size & voltage |
Battery Size Reference (All Common Battery Sizes)
| Category | Size Name / Code | Dimensions (L × W × H, mm/inch) | Typical Voltage | Typical Applications |
|---|---|---|---|---|
| BCI Group | Group 24 | 260 × 168 × 215mm / 10.24 × 6.61 × 8.46 inch |
12V | Marine, RV, Solar |
| BCI Group | Group 24F | 260 × 168 × 225mm / 10.24 × 6.61 × 8.86 inch | 12V | Automotive |
| BCI Group | Group 27 | 306 × 173 × 225mm / 12.05 × 6.81 × 8.86 inch | 12V | Marine, Solar |
| BCI Group | Group 31 | 330 × 173 × 240mm / 12.99 × 6.81 × 9.45 inch | 12V | Truck, Marine |
| BCI Group | Group 34 | 260 × 173 × 205mm / 10.24 × 6.81 × 8.07 inch | 12V | Automotive |
| BCI Group | Group 35 | 230 × 175 × 225mm / 9.06 × 6.89 × 8.86 inch | 12V | Automotive |
| BCI Group | Group 51 / 51R | 238 × 129 × 223mm / 9.37 × 5.08 × 8.78 inch | 12V | Automotive |
| BCI Group | Group 65 | 315 × 175 × 190mm / 12.40 × 6.89 × 7.48 inch | 12V | Automotive |
| BCI Group | GC2 | 260 × 180 × 275mm / 10.24 × 7.09 × 10.83 inch | 6V | Golf Cart, RV |
| BCI Group | 8D | 527 x 283 x 250mm / 20.75 x 11.13 x 9.8 inch |
6V | Golf Cart, RV |
| DIN / EN | L1 (H4) | 207 × 175 × 175mm / 8.15 × 6.89 × 6.89 inch | 12V | Small vehicles |
| DIN / EN | L2 (H5) | 242 × 175 × 175mm / 9.53 × 6.89 × 6.89 inch | 12V | Passenger vehicles |
| DIN / EN | L3 (H6) | 278 × 175 × 190mm / 10.94 × 6.89 × 7.48 inch | 12V | Passenger vehicles |
| DIN / EN | L4 (H7) | 315 × 175 × 190mm / 12.40 × 6.89 × 7.48 inch | 12V | SUVs, Vans |
| DIN / EN | L5 (H8) | 353 × 175 × 190mm / 13.90 × 6.89 × 7.48 inch | 12V | Vans |
| DIN / EN | L6 (H9) | 393 × 175 × 190mm / 15.47 × 6.89 × 7.48 inch | 12V | Commercial vehicles |
| SLA / VRLA | NP7-12 (7Ah) | 151 × 65 × 93mm / 5.94 × 2.56 × 3.66 inch | 12V | UPS, Alarm systems |
| SLA / VRLA | 9Ah | 151 × 65 × 94mm / 5.94 × 2.56 × 3.70 inch | 12V | UPS |
| SLA / VRLA | 12Ah | 151 × 98 × 95mm / 5.94 × 3.86 × 3.74 inch | 12V | Backup power |
| SLA / VRLA | 18Ah | 181 × 77 × 167mm / 7.13 × 3.03 × 6.57 inch | 12V | Emergency lighting |
| SLA / VRLA | 26Ah | 166 × 175 × 125mm / 6.54 × 6.89 × 4.92 inch | 12V | Industrial backup |
| SLA / VRLA | 33Ah | 195 × 130 × 155mm / 7.68 × 5.12 × 6.10 inch | 12V | UPS |
| SLA / VRLA | 40Ah | 197 × 165 × 170mm / 7.76 × 6.50 × 6.69 inch | 12V | Backup systems |
| SLA / VRLA | 55Ah | 229 × 138 × 210mm / 9.02 × 5.43 × 8.27 inch | 12V | Backup power |
| SLA / VRLA | 65Ah | 350 × 167 × 180mm / 13.78 × 6.57 × 7.09 inch | 12V | Industrial UPS |
| SLA / VRLA | 100 Ah | 330 × 173 × 215mm / 12.99 × 6.81 × 8.46 inch | 12V | Solar, Backup |
Note: Battery size standards define physical dimensions and terminal layout only. Capacity and performance depend on battery chemistry and design. Please confirm dimensions and terminal orientation before installation.
Choosing the Right Battery Size Standard
Selecting the correct battery size standard depends on:
- Installation space and mounting design
- Regional market requirements
- Application-specific performance needs
- Replacement and maintenance considerations
At Litech Power, we offer custom battery solutions. Our solutions are available in BCI Group, DIN / EN, and SLA / VRLA standardized formats. Our products support many industrial, energy storage, and mobility uses.
About Litech Power
Litech Power focuses on high-quality lithium and lead-acid batteries. They offer both standard and custom battery packs for global markets.
From dimension matching to electrical performance optimization, we help customers ensure seamless integration and long-term reliability.
