BCI Battery Groups Size Charts

optima red top batteryBCI battery groups are standardized battery sizes, allowing the users to find more easily the proper battery replacements.

Knowing exact BCI battery group of the old battery helps finding the new battery replacement, although knowing just the BCI group size is often not enough. Many manufacturers label their batteries as 'the best fit', making them sometimes slightly larger than 'standard size'.

If the battery compartment is tight fit to the standard battery size, such 'slightly larger' battery may not fit ...

The most popular BCI battery groups sizes and their dimensions are given in the following chart:

BCI Battery Group Size L x W x H (inches) L x W x H (cm)
Group 24 Battery 10.25 x 6.8125 x 8.875 26 x 17.3 x 22.5
Group 27 Battery 12.0625 x 6.8125 x 8.875 30.6 x 17.3 x 22.5
Group 31 Battery 13 x 6.8125 x 9.4375 33 x 17.3 x 24
Group 34 Battery 10.25 x 6.8125 x 7.875 26 x 17.3 x 20
Group 35 Battery 9.0625 x 6.875 x 8.875 23 x 17.5 x 22.5
Group 51 Battery 9.374 x 5.0625 x 8.8125 23.8 x 12.9 x 22.3
Group 65 Battery 12.0625 x 7.5 x 7.5625 30.6 x 19 x 19.2
Group 78 Battery 10.25 x 7.0625 x 7.6875 26 x 17.9 x 19.6

Again, before getting a new battery for your car, truck, RV, boat or similar, it is good practice to note volts (usually 12 volts), capacity, type (AGM, Gel cell, wet/flooded, lithium etc.), CCA, MCA, terminal type and orientation, Reserve Capacity (RC), BCI Group, but also actual dimensions of the battery - better safe than sorry :)

The most common BCI battery groups sizes are listed in the following chart:

BCI Group Size L (mm) W (mm) H (mm) L (inches) W (inches) H (inches)
21 208 173 222 8 3/16 6 13/16 8 3/4
21R 208 173 222 8 3/16 6 13/16 8 3/4
22F 241 175 211 9 1/2 6 7/8 8 5/16
22HF 241 175 229 9 1/2 6 7/8 9
22NF 240 140 227 9 7/16 5 1/2 8 15/16
22R 229 175 211 9 6 7/8 8 5/16
Group 24 Battery 260 173 225 10 1/4 6 13/16 8 7/8
24F 273 173 229 10 3/4 6 13/16 9
24H 260 173 238 10 1/4 6 13/16 9 3/8
24R 260 173 229 10 1/4 6 13/16 9
24T 260 173 248 10 1/4 6 13/16 9 3/4
25 230 175 225 9 1/16 6 7/8 8 7/8
26 208 173 197 8 3/16 6 13/16 7 3/4
26R 208 173 197 8 3/16 6 13/16 7 3/4
27 306 173 225 12 1/16 6 13/16 8 7/8
27F 318 173 227 12 1/2 6 13/16 8 15/16
27H 298 173 235 11 3/4 6 13/16 9 1/4
29NF 330 140 227 13 5 1/2 8 15/16
33 338 173 238 13 5/16 6 13/16 9 3/8
34 260 173 200 10 1/4 6 13/16 7 7/8
34R 260 173 200 10 1/4 6 13/16 7 7/8
35 230 175 225 9 1/16 6 7/8 8 7/8
36R 263 183 206 10 3/8 7 1/4 8 1/8
40R 277 175 175 10 15/16 6 7/8 6 7/8
41 293 175 175 11 3/16 6 7/8 6 7/8
42 243 173 173 9 5/16 6 13/16 6 13/16
43 334 175 205 13 1/8 6 7/8 8 1/16
45 240 140 227 9 7/16 5 1/2 8 15/16
46 273 173 229 10 3/4 6 13/16 9
47 246 175 190 9 11/16 6 7/8 7 1/2
48 306 175 192 12 1/16 6 7/8 7 9/16
49 381 175 192 15 6 7/8 7 3/16
50 343 127 254 13 1/2 5 10
51 238 129 223 9 3/8 5 1/16 8 13/16
51R 238 129 223 9 3/8 5 1/16 8 13/16
52 186 147 210 7 5/16 5 13/16 8 1/4
53 330 119 210 13 4 11/16 8 1/4
54 186 154 212 7 5/16 6 1/16 8 3/8
55 218 154 212 8 5/8 6 1/16 8 3/8
56 254 154 212 10 6 1/16 8 3/8
57 205 183 177 8 1/16 7 3/16 6 15/16
58 255 183 177 10 1/16 7 3/16 6 15/16
58R 255 183 177 10 1/16 7 3/16 6 15/16
59 255 193 196 10 1/16 7 5/8 7 3/4
60 332 160 225 13 1/16 6 5/16 8 7/8
61 192 162 225 7 9/16 6 3/8 8 7/8
62 225 162 225 8 7/8 6 3/8 8 7/8
63 258 162 225 10 3/16 6 3/8 8 7/8
64 296 162 225 11 11/16 6 3/8 8 7/8
65 306 190 192 12 1/16 7 1/2 7 9/16
70 208 179 196 8 3/16 7 1/16 7 11/16
71 208 179 216 8 3/16 7 1/16 8 1/2
72 230 179 210 9 1/16 7 1/16 8 1/4
73 230 179 216 9 1/16 7 1/16 8 1/2
74 260 184 222 10 1/4 7 1/4 8 3/4
75 230 179 196 9 1/16 7 1/16 7 11/16
76 334 179 216 13 1/8 7 1/16 8 1/2
78 260 179 196 10 1/4 7 1/16 7 11/16
85 230 173 203 9 1/16 6 13/16 8
86 230 173 203 9 1/16 6 13/16 8
90 246 175 175 9 11/16 6 7/8 6 7/8
91 280 175 175 11 6 7/8 6 7/8
92 317 175 175 12 1/2 6 7/8 6 7/8
93 354 175 175 15 6 7/8 6 7/8
95R 394 175 190 15 9/16 6 7/8 7 1/2
96R 242 173 175 9 9/16 6 13/16 6 7/8
97R 252 175 190 9 15/16 6 7/8 7 1/2
98R 283 175 190 11 3/16 6 7/8 7 1/2
Passenger Car and Light Commercial 6 V Batteries (3 Cells)
BCI Group Size L (mm) W (mm) H (mm) L (inches) W (inches) H (inches)
1 232 181 238 9 1/8 7 1/8 9 3/8
2 264 181 238 10 3/8 7 1/8 9 3/8
2E 492 105 232 19 7/16 4 1/8 9 1/8
2N 254 141 227 10 5 9/16 8 15/16
17HF 187 175 229 7 3/8 6 7/8 9
Heavy Duty Commercial 12 V Batteries (6 Cells)
BCI Group Size L (mm) W (mm) H (mm) L (inches) W (inches) H (inches)
4D 527 222 250 20 3/4 8 3/4 9 7/8
6D 527 254 260 20 3/4 10 10 1/4
8D 527 283 250 20 3/4 11 1/8 9 7/8
28 261 173 240 10 5/16 6 13/16 9 7/16
29H 334 171 232 13 1/8 6 3/4 9 1/8
30H 343 173 235 13 1/2 6 13/16 9 1/4
31 330 173 240 13 6 13/16 9 7/16
Electric Vehicle 6 V Batteries (3 Cells)
BCI Group Size L (mm) W (mm) H (mm) L (inches) W (inches) H (inches)
GC2 264 183 270 10 3/8 7 3/16 10 5/8
GC2H 264 183 295 10 3/8 7 3/16 11 5/8

As one can see, some batteries are very similar in size and can be used interchangeably.

Again, just in case, don't check just BCI number of your old battery - be sure to measure its actual size as well, but also voltage, capacity, terminal types and orientation, Reserve Capacity (RC), CCA, MCA, chemistry etc.