Marine 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.
The 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 - a larger battery can't fit into the smaller compartment, while smaller can, but must be additionally fixed to avoid any damage to the boat or battery.
For the list of most popular Powersports batteries, please check our Powersports, ATVs, and Motorcycle Battery Cross Reference Chart.
Most popular marine, automotive, industry, and off-the-grid battery group sizes are listed in the following chart:
BCI Battery Group Size | L x W x H (inches/mm) | Typical Capacity (Ah) | Typical CCA (Amps) | Typical RC (min) |
Group 4D Batteries | 20.75 x 8.75 x 9.875 527 x 222 x 250 |
170 - 200 | 1200 - 1500 | 350 - 470 |
Group 8D Batteries | 20.75 x 11.125 x 9.875 527 x 283 x 250 |
200 - 350 | 1450 - 2700 | 460 - 780 |
Group 24 Batteries | 10.25 x 6.8125 x 8.875 260 x 173 x 225 |
75 - 85 | 500 - 840 | 140 - 180 |
Group 27 Batteries | 12.0625 x 6.8125 x 8.875 306 x 173 x 225 |
66 - 110 | 640 - 870 | 140 - 220 |
Group 31 Batteries | 13 x 6.8125 x 9.4375 330 x 173 x 240 |
75 - 125 | 600 - 1150 | 155 - 240 |
Group 34 Batteries | 10.25 x 6.8125 x 7.875 260 x 173 x 200 |
50 - 75 | 750 - 880 | 100 - 145 |
Following the BCI battery group size chart lists the most common battery sizes.
Note: we have really tried to verify the information provided in this chart, 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 |
Light Commercial Vehicles and Passenger Car Batteries 12 V Batteries (6 Cells) | |||||||
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 |
Group 27 | 306 | 173 | 225 | 12 1/16 | 6 13/16 | 8 7/8 | Group 27 Battery |
Group 27F | 318 | 173 | 227 | 12 1/2 | 6 13/16 | 8 15/16 | Group 27F Battery |
Group 27H | 298 | 173 | 235 | 11 3/4 | 6 13/16 | 9 1/4 | Group 27H Battery |
Group 27R | 306 | 173 | 225 | 12 1/16 | 6 13/16 | 8 7/8 | Group 27R 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 |
Group 34 | 260 | 173 | 200 | 10 1/4 | 6 13/16 | 7 7/8 | Group 34 Battery |
Group 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 |
94R | 315 | 175 | 190 | 12 3/8 | 6 7/8 | 7 1/2 | Group 94R 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 |
99 | 207 | 175 | 175 | 8 1/8 | 6 7/8 | 6 7/8 | Group 99 Battery |
99R | 210 | 175 | 175 | 8 1/4 | 6 7/8 | 6 7/8 | Group 99R Battery |
100 | 260 | 179 | 188 | 10 1/4 | 7 1/16 | 7 3/8 | Group 100 Battery |
101 | 260 | 179 | 170 | 10 1/4 | 7 1/16 | 6 11/16 | Group 101 Battery |
121R | 208 | 177 | 215 | 8 1/4 | 7 | 8 1/2 | Group 121R Battery |
124 | 265 | 175 | 214 | 10 7/16 | 6 7/8 | 8 7/16 | Group 124 Battery |
124R | 262 | 177 | 218 | 10 3/8 | 7 | 8 5/16 | Group 124R Battery |
151R | 188 | 125 | 225 | 7 3/8 | 4 15/16 | 8 7/8 | Group 151R Battery |
Light Commercial Vehicles and Passenger Car 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 |
19L | 216 | 178 | 191 | 8 1/2 | 7 | 7 1/2 | Group 19L Battery |
Special Tractor and Heavy Duty Commercial 12 V Batteries (6 Cells) | |||||||
3EE | 491 | 111 | 225 | 19 5/16 | 4 3/8 | 8 7/8 | Group 3EE Battery |
3ET | 491 | 111 | 249 | 19 5/16 | 4 3/8 | 9 13/16 | Group 3ET Battery |
Group 4D | 527 | 222 | 250 | 20 3/4 | 8 3/4 | 9 7/8 | Group 4D Battery |
4DLT | 508 | 208 | 202 | 20 | 8 3/16 | 7 15/16 | Group 4DLT Battery |
Group 6D | 527 | 254 | 260 | 20 3/4 | 10 | 10 1/4 | Group 6D Battery |
Group 8D | 527 | 283 | 250 | 20 3/4 | 11 1/8 | 9 7/8 | Group 8D Battery |
12T | 179 | 177 | 202 | 7 1/16 | 6 15/16 | 7 15/16 | Group 12T 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 |
Group 31 | 330 | 173 | 240 | 13 | 6 13/16 | 9 7/16 | Group 31 Battery |
Special Tractor and Heavy Duty Commercial 6 V Batteries (3 Cells) | |||||||
3 | 298 | 181 | 238 | 11 3/4 | 7 1/8 | 9 3/8 | Group 3 Battery |
3EH | 491 | 111 | 249 | 19 5/16 | 4 3/8 | 9 13/16 | Group 3EH Battery |
4 | 334 | 181 | 238 | 13 1/8 | 7 1/8 | 9 3/8 | Group 4 Battery |
4EH | 491 | 127 | 249 | 19 5/16 | 5 | 9 13/16 | Group 4EH Battery |
5D | 349 | 181 | 238 | 13 3/4 | 7 1/8 | 9 3/8 | Group 5D Battery |
7D | 413 | 181 | 238 | 16 1/4 | 7 1/8 | 9 3/8 | Group 7D 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 |
Electric Vehicle 8 V Batteries (4 Cells) | |||||||
GC8 | 264 | 183 | 277 | 10 3/8 | 7 3/16 | 10 7/8 | Group GC8 Battery |
GC8H | 264 | 183 | 295 | 10 3/8 | 7 3/16 | 11 5/8 | Group GC8H Battery |
Electric Vehicle 12 V Batteries (6 Cells) | |||||||
GC12 | 327 | 183 | 277 | 12 7/8 | 7 3/16 | 10 7/8 | Group GC12 Battery |
General Purpose 12 V Batteries (6 Cells) | |||||||
U1 | 197 | 132 | 186 | 7 3/4 | 5 3/16 | 7 5/16 | Group U1 Battery |
U1R | 197 | 132 | 186 | 7 3/4 | 5 3/16 | 7 5/16 | Group U1R Battery |
U2 | 160 | 132 | 181 | 6 5/16 | 5 3/16 | 7 1/8 | Group U2 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.
The following cross reference chart lists the most popular BCI, DIN, and EN standards battery groups and their dimensions.
Maximum BCI Battery Dimensions (L x W x H, inch/mm) |
BCI Group | Maximum DIN/EN Battery Dimensions (L x W x H mm) |
DIN Codes | EN Codes |
10 15/16 x 6 7/8 x 6 7/8 277 x 175 x 175 |
40R | 278 x 175 x 175 | T6, LB3 | 66LB |
11 3/16 x 6 7/8 x 6 7/8 293 x 175 x 175 |
41 | 293 x 175 x 175 | T65 | 54LB |
9 5/16 x 6 13/16 x 6 13/16 243 x 173 x 173 |
42 | 242 x 175 x 175 | T5, LB2 | 45LB |
9 11/16 x 6 7/8 x 7 1/2 246 x 175 x 190 |
47 | 242 x 175 x 190 | H5, L2 | 55L2 |
12 1/16 x 6 7/8 x 7 9/16 306 x 175 x 192 |
48 | 278 x 175 x 190 | H6, L3 | 66L3 |
15 x 6 7/8 x 7 3/16 381 x 175 x 192 |
49 | 354 x 175 x 190 | H8, L5 | 88L5 |
9 11/16 x 6 7/8 x 6 7/8 246 x 175 x 175 |
90 | 242 x 175 x 175 | T5, LB2 | 45LB |
11 x 6 7/8 x 6 7/8 280 x 175 x 175 |
91 | 278 x 175 x 175 | T6, LB3 | 66LB |
12 1/2 x 6 7/8 x 6 7/8 317 x 175 x 175 |
92 | 315 x 175 x 175 | T7, LB4 | 77LB |
15 x 6 7/8 x 6 7/8 354 x 175 x 175 |
93 | 354 x 175 x 175 | T8, LB5 | 88LB |
12 3/8 x 6 7/8 x 7 1/2 315 x 175 x 190 |
94R | 315 x 175 x 190 | H7, L4 | 77L4 |
15 9/16 x 6 7/8 x 7 1/2 394 x 175 x 190 |
95R | 394 x 175 x 190 | H9, L6 | - |
9 15/16 x 6 7/8 x 7 1/2 252 x 175 x 190 |
97R | 252 x 175 190 | H5, L2 | 55L2 |
11 3/16 x 6 7/8 x 7 1/2 283 x 175 x 190 |
98R | 283 x 175 x 190 | H6, L3 | 66L3 |
8 1/8 x 6 7/8 x 6 7/8 207 x 175 x 175 |
99 | 207 x 175 x 175 | T4, LB1 | 36LB |
8 1/4 x 6 7/8 x 6 7/8 210 x 175 x 175 |
99R | 210 x 175 x 175 | T4, LB1 | 36LB |
- | - | 175 x 175 x 190 | H3, L0 | 32L0 |
- | - | 297 x 175 x 190 | H4, L1 | 45L1 |
Note: this chart list 'just' battery dimensions and not their orientation, the way they are assembled, the presence of lifting edge, base hold-down type, and similar.
Most of the batteries in the list are of very similar dimensions, except two models (48 and 49) which have a slightly larger size differences.
For example, it is generally considered that BCI Group 48 (306 x 175 x 192 mm, positive terminal location: Right) is equivalent to the DIN/EN battery groups labeled as H6, L3 and 66L3 (278 x 175 x 190 mm, positive terminal location: Right).
However, if You dig a little bit deeper in the BCI Battery Groups Chart, You can find that the BCI Battery Group 98R (283 x 175 x 190 mm, positive terminal location: Right) is a better match to the DIN/EN battery groups labeled as H6, L3 and/or 66L3.
Again, if in doubt, always measure your battery compartment and check actual battery size, not just the claimed battery group, battery orientation, terminal types, etc.
Here is the list of our BCI Battery Group articles, ordered according to the date added or modified:
BCI Group 34 Batteries are very popular car, boat, and light industry batteries, used in deep-cycle, dual-purpose, and starting/cranking applications.
Most modern group 34 batteries are Sealed Lead-Acid (SLA) Absorbent Glass Mat (AGM) batteries, but flooded batteries are still present. Also, lithium group 34 batteries are becoming more common. But, group 34 AGM batteries are still going on strong, offering a strong and reliable source of electric power at an acceptable price.
BCI Group 27 batteries are very popular industrial, marine and automotive batteries, commonly designed as deep cycle or dual-purpose batteries, with cranking-only group 27 batteries being rather rare.
BCI Group 27 batteries are commonly used in applications where larger and more powerful BCI Group 31 batteries are too large and heavy, but strong and reliable battery is nonetheless, required, like UPS batteries, trolling motor batteries, in the security and medical systems, as wheelchair battery, as RV/ATV/SUV battery, etc.
BCI Group 24 Batteries are very popular general-purpose batteries, commonly used as wheelchair batteries, trolling motor batteries, in off-the-grid systems, as sump pump backup battery, etc.
Most modern BCI Group 24 batteries are Sealed Lead Acid (SLA) Absorbent Glass Mat (AGM) batteries, although there are also other types and chemistries on the market as well.
BCI Group 4D and 8D batteries are large and heavy lead-acid batteries, that can store large amounts of energy and release it in both short but strong energy bursts or slowly, over longer periods of time.
BCI Group 4D and 8D batteries are not used as often as smaller batteries from BCI groups 31, 24, or 27, but are nonetheless very popular in automotive, industrial and marine applications where strong and reliable batteries are required.
BCI group 31 batteries are very popular batteries, commonly used in automotive, marine, industrial, off-the-grid and other similar applications where the atteries are often pushed to their limits.
Group 31 batteries differ in internal construction and exact chemistry, with the lead-acid AGM and Gel group 31 batteries being most common, and with lithium group 31 batteries becoming more and more popular.