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

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
Group 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
29H 334 171 232 13 1/8 6 3/4 9 1/8 Group 29H 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
Group 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
Group 51 238 129 223 9 3/8 5 1/16 8 13/16 Group 51 Battery
Group 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
Group 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

Note: Amazon affiliate links open in the new windows, feel free to check them.

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.

BCI, DIN, and EN Battery Groups Cross Reference Chart

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:

Best BCI Group 22NF Battery

weize lfp1255 mBCI Group 22NF batteries are very popular, mid-size, general-purpose batteries, commonly used as wheelchair batteries, trolling batteries, as a second car deep cycle battery, as small inverter battery, in medical and security applications, etc.

BCI Group 22NF batteries are mostly spill-proof AGM and Gel-Cell lead-acid batteries, although lithium Group 22NF batteries have started to appear on the market as well.

Published: June 2, 2021.

Best BCI Group 51 and Group 51R Batteries

group 51 batteries mBCI Group 51 and Group 51R batteries are very popular automotive and marine batteries, used as starting/cranking batteries and for powering other devices while the engine is turned off.

While older group 51/51R batteries were almost exclusively wet/flooded starting lead-acid batteries, modern group 51/51R batteries are very often designed as dual-purpose, maintenance-free AGM batteries, with lithium group 51/51R batteries slowly becoming more and more popular.

Published: May 14, 2021.

Best BCI Group 65 Batteries

group 65 battery mBCI Group 65 batteries are mid-range automotive and light industry batteries, often used in marine applications as starting/cranking batteries and as deep-cycle/dual-purpose batteries in both single- and dual-battery systems.

The most popular BCI Group 65 battery type is a lead-acid AGM battery, although lithium batteries are becoming more and more popular as well.

Published: February 24, 2021.

BCI Group 35 Batteries

northstar nsb agm35 w150BCI Group 35 batteries are popular general-purpose and starting batteries, often used in marine, automotive and even industrial applications where space is limited, but one needs a strong and reliable power source for cranking gas and diesel small-to-medium large engines, for medical and security systems, for electric vehicles and similar.

BCI Group 35 batteries are sometimes used as backup batteries for smaller sump pump systems, for smaller off-the-grid applications and for other purposes where their size, capacity, and performances fit perfectly.

Published: February 23, 2021.

Best BCI Group 34 Battery

odyssey 34m 1500 w150pxBCI 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.

Published: December 18, 2020.

Best Deep Cycle BCI Group 27 Batteries

group 27 mBCI 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.

Published: November 30, 2020.

BCI Group 24 Batteries

group24 battery w150BCI 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.

Published: July 1, 2020.

BCI Group 4D and 8D Batteries - Features and Specifications

group 4d battery mBCI 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.

Published: May 16, 2020.

Best BCI Group 31 Batteries

odyssey 31m pc2150 1mBCI 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.

Published: March 21, 2020.

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