BCI Battery Groups

odyssey 31m pc2150 1mMarine batteries come in various sizes, having different capacities, voltages and performances in general.

Depending on the size, batteries are categorized in various size groups. Of course, there are always 'special' size batteries, so pay attention when buying new batteries.

Battery Dimensions By Group Size

Following tables show industry standard group sizes according to their external dimensions. Battery compartments are usually made for a certain battery standard, so knowing both values is important - larger battery can't fit into smaller compartment, while smaller can, but must be additionally fixed to avoid any damage to the boat or battery.

Most popular battery group sizes:

Group Size LxWxH (inches) LxWxH (mm)
34 10.25x6.8125x7.875 260x173x200
24 10.25x6.8125x8.875 260x173x225
24H 10.25x6.8125x9.375 260x173x238
27  12.0625x6.8125x8.875 306x173x225
29H 13.125x6.725x9.125 333x171x232
30H 13.5x6.8125x9.25 343x173x235
31 13x6.8125x9.4375 330x173x240

Following BCI battery group size chart lists most common battery sizes.

Note: we have really tried to verify information provided in this table, but there are no warranties of any kind.

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

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Many BCI battery groups differ by only fraction of an inch and they can be used interchangeably, if and only if the new battery fits the 'old' battery tray/box, and features equal or better charging/discharging characteristics compared to the old battery.