Battery Equivalents and Replacements

BCI Group 22NF Battery

BCI Group 22NF battery is a general-purpose mid-range battery used as backup/standby battery, wheelchair battery, trolling motor battery, off-the-grid battery, as starting battery for smaller gas and diesel engines, and similar.

As such, 22NF battery is manufactured by many battery brands as wet/flooded, AGM, Gel-Cell lead-acid battery. Also, lithium 22NF batteries are also emerging on the market, offering great weight savings and other benefits.

 BCI Group 22NF Batteries Features and Specifications

BCI Group 22NF batteries feature physical dimensions of (L x W x H) 9.4375 x 5.5 x 8.9375 inches (9 7/16 x 5 1/2 x 8 15/16 inches, 240 x 140 x 227 mm), a nominal voltage of 12 volts, a nominal (20h) capacity in the 50-60 Ah range, 90-135 minutes Reserve Capacity and they weigh between 15-18 pounds (lithium group 22NF batteries) and ~34-45 pounds (lead-acid group 22NF batteries).

mighty max ml55 12

In order to avoid confusion about "22" groups, one must note that there are several BCI battery groups that have the number "22" in their label, followed by one or two letters, as listed in the following table:

Battery Group Battery Size (mm) Battery Size (inches)
22F 241 x 175 x 211 9 1/2 x 6 7/8 x 8 5/16
22HF 241 x 175 x 229 9 1/2 x 6 7/8 x 9
22NF 240 x 140 x 227 9 7/16 x 5 1/2 x 8 15/16
22R 229 x 175 x 211 9 x 6 7/8 x 8 5/16

This article is about BCI Group 22NF batteries.

Group 22NF batteries feature similar length and height just as other "22" group batteries, but 22NF batteries are narrower - battery compartments intended for 22NF batteries rarely can accept other "22" batteries, so be careful when choosing the new battery.

Most Popular BCI Group 22NF Batteries

The following chart lists some of the most popular BCI group 22NF batteries on the market with their most important features and specifications:

Model Battery Type Cell Type Ah CCA MCA RC Weight (lbs/kg)
Absolute UX12550 Dual Purpose AGM 55 493 641 90 40.1 lbs; 17.5 kg
AJC 12V55Ah Deep Cycle AGM 55 - - - 40.1 lbs; 17.5 kg
Casil CA12550 Deep Cycle AGM 55 - - - 35 lbs; 15.9 kg
ExpertPower EXP12500 Deep Cycle AGM 55 - - - 36.0 lbs; 16.3 kg
ExpertPower EXP55-Gel Deep Cycle Gel-Cell 55 - - - 37.0 lbs; 16.8 kg
Interstate DCM0055 Deep Cycle AGM 55 - - - 37.5 lbs; 17.0 kg
Mighty Max ML55-12 Deep Cycle AGM 58 - - - 37.0 lbs; 16.8 kg
Mighty Max ML5512LI Deep Cycle LiFePO4 55 - - ~130 19.0 lbs; 8.6 kg
MK 22NF Deep Cycle AGM 51 - - - 37.0 lbs; 16.8 kg
PowerSonic PS-12550 Deep Cycle AGM 55 - - - 36.0 lbs; 16.3 kg
SigmasTek SP12-55 Deep Cycle AGM 55 - - - 36.0 lbs; 16.3 kg
SigmasTek SPG12-55 Deep Cycle Gel-Cell 51 - - - 36.6 lbs; 16.6 kg
UPG UB12550 AGM Deep Cycle AGM 55 - - - 45 lbs; 20.4 kg
UPG UB12550 Gel Deep Cycle Gel-Cell 55 - - - 38.6 lbs; 17.5 kg
UPS 12V55Ah Deep Cycle AGM 55 - - - 39.7 lbs; 18 kg
VMAXTANKS LFP22-1255 Deep Cycle LiFePO4 55 - - 120+ 15.5 lbs; 7.1 kg
VMAXTANKS MB96-60 Deep Cycle AGM 60 - - 125 43 lbs; 19.5 kg
VMAXTANKS SLR60 Deep Cycle AGM 60 - - 135 43 lbs; 19.5 kg
Weize LFP1255 Deep Cycle AGM 55/10h - - - 34.2 lbs; 15.5 kg
XS Power D5100 XS Dual Purpose AGM 60 - 745 131 43.2 lbs; 19.6 kg
XS Power D5100R XS Dual Purpose AGM 60 - 745 131 43.2; 19.6 kg

Note: Amazon links ('Model' column) open in the new windows, feel free to check them for the most up-to-date offers and prices.

Most group 22NF batteries are general-purpose, deep-cycle Absorbent Glass Mat (AGM) Sealed Lead-Acid (SLA) batteries, featuring an average 20h capacity in the 50-60 Ah range, Reserve Capacity of 130-135 minutes, and the weight of 34-43 pounds.

Some brands also offer Gel-Cell group 22NF batteries, while flooded/wet 22NF batteries are being slowly phased out - AGM and Gel-Cell 22NF batteries are mostly spill-proof, maintenance-free, and vibration-resistant batteries.

Most group 22NF batteries feature NB (Nuts and Bolts) battery terminals, but there are also models that feature M6 or similar battery terminals.

Lithium group 22NF batteries are not as common as lead-acid 22NF batteries, but they feature a similar 20h capacity (~55 Ah) which doesn't drop when the batteries are being discharged with strong currents (0.33-1.0 C, for example).

Also, lithium batteries are 2-3x lighter and support a much larger number of charging/discharging cycles, sometimes up to 2000-3000 cycles down to 80-100% DoD (Depth of Discharge).

On the other hand, lithium batteries must be recharged using dedicated lithium battery chargers and are sensitive to being discharged by strong currents - the built-in Battery Management System shuts the battery off when the discharge thresholds are met.

weize lfp1255

How to Charge BCI Group 22NF Battery

If the battery is part of an electric system that also features a battery charger (for example, a garden tractor with an internal combustion engine, alternator, and a charge controller), let the battery charger take care of charging the battery.

When the lead-acid 22NF battery is charged using a dedicated battery charger, one should go for an advanced AGM battery charger that allows the user to set the battery application mode (Float/Standby or Cyclic Use), exact battery chemistry (wet/flooded, AGM, Gel-Cell), that features temperature probe for temperature correction and one that analyzes the battery first before charging it.

Most group 22NF batteries feature maximum allowed charging current in the 15-20 Amps range, making 10 Amps battery chargers highly recommended.

Amazon Search:

- 10 Amps AGM Battery Charger

- 15 Amps AGM Battery Charger

- Battery Maintainer

Note: Amazon links open in the new windows, feel free to check them for the most up-to-date offers and prices.

For example, if the 12V 55Ah battery is discharged down to 50% DoD (or SoC), a 10 Amp intelligent AGM battery charger requires ~3 hours to recharge it fully.

BCI Group 22NF Batteries as Trolling Motor Batteries

BCI Group 22NF batteries are commonly used as trolling motor batteries for small boats, pontoons, and kayaks - such trolling motors draw a maximum current of 30-35 Amps and an average current of 15-20 Amps.

With an average 55Ah 20h capacity, most 22NF group batteries are able to provide 30-35 Amps for at least one hour and 15-20 Amps for at least 2-3 hours.

However, the quality of batteries varies and the capacity loss due to the higher discharge current also varies.

The following table shows constant current discharge values (at 77°F, 25°C) of the very popular Mighty Max ML55-12 deep cycle AGM battery:

Cell End Point Voltage Battery End Point Voltage 5 min 10 min 15 min 30 min 1h 3h 5h 10h 20h
1.60 V 9.6 V 172 130 98.0 58.2 35.2 14.5 9.98 5.69 2.98
1.65 V 9.9 V 162 123 94.0 56.5 34.4 14.3 9.88 5.65 2.97
1.70 V 10.2 V 152 115 89.5 54.5 33.6 14.0 9.75 5.60 2.95
1.75 V 10.5 V 141 108 84.4 52.9 32.7 13.7 9.60 5.55 2.93
1.80 V 10.8 V 128 100 80.5 51.0 31.6 13.4 9.43 5.50 2.90

group 22nf mObviously, group 22NF batteries may also be used for powering larger trolling motors that draw 50 or so Amps, but the capacity drop is significant - Mighty Max ML55-12 battery is able to provide 51 Amps for 30 minutes (effective capacity drop from 58Ah/20h and 55Ah/10h, down to 25.5Ah/0.5h) which is enough for most 45-55 lbs trolling motors.

Note: such capacity drop is a normal occurrence for lead-acid batteries, with Mighty Max ML55-12 being one of the best performers in its class, especially considering its price - that is why it is one of the most popular group 22NF batteries on the market.

If You need an electric trolling motor battery with a longer runtime, feel free to check our How to Choose the Best Trolling Motor Battery? article.

BCI Group 22NF Batteries as Wheelchair Batteries

Wheelchair motors differ in strength, but on average one may expect two 150-300W (or even stronger) motors.

When calculating expect runtime, one must also note a number of batteries which is usually one (12V systems) or two (12V or 24V systems).

The following table shows constant power discharge values (at 77°F, 25°C) of the Mighty Max ML55-12 battery:

Cell End Point Voltage Battery End Point Voltage 5 min 10 min 15 min 30 min 45 min 1h 2h 3h 5h
1.60 V 9.6 V 1920 1482 1146 690 530.4 428.4 255.0 182.4 116.4
1.65 V 9.9 V 1860 1398 1098 678 348.4 418.8 250.2 177.0 114.6
1.70 V  10.2 V 1746 1320 1056 666 511.8 409.2 244.8  173.4 112.8
1.75 V  10.5 V 1626 1242 1008 654 500.4 399.6 238.8 169.8 112.2
1.80 V  10.8 V 1542 1152 954 642 487.2 389.4 232.8 166.2 111.0

For example, if our hypothetical wheelchair features 2x250W electric motors and its electric system is a 24V system consisting of two 22NF batteries connected in series, then two Mighty Max ML55-12 batteries offer a runtime of ~2h with the voltage drop down to 9.9 volts.

Since wheelchairs are rarely used at full power all the time, actual runtime may be for days - in that case, charging the batteries during the night and using them during the day, ensure that the batteries will almost never be discharged below 50%, prolonging their lifetime.

BCI Group 22NF Batteries as Inverter Batteries

In the case of emergencies and blackouts, group 22NF batteries may be used as small inverter batteries, allowing the user to run smaller appliances or recharge the laptops, tablets, phones, and similar.

If the 300W power inverter with 90% efficiency is connected to the Mighty Max ML55-12 or similar battery, the battery must provide at least:

P(battery) = P(inverter) / 0.90 = ~333 watts

If we check the constant power discharge table for the Mighty Max ML55-12, we see that that battery is able to provide such power for 1+ hours without the voltage dropping below 10.8 volts.

And if the power inverter is not used at its full power all the time, the runtime can be much longer.

 BCI Group 22NF Batteries as Starting Battery

Most group 22NF batteries are designed as deep-cycle batteries and are not very suitable as starting batteries.

For example, the Mighty Max ML55-12 battery features an 8 mΩ internal resistance and it is able to provide 550 Amps for 5 seconds at 77°F (25°C).

However, several dual-purpose 22NF battery models are able to provide 450-500 CCA and 640-745 CA Amps.

But, some garden tractors and similar vehicles use deep-cycle group 22NF batteries as starting batteries for several reasons:

- such vehicles come with gas/diesel engines that don't require more than 200-300 Amps when starting,

- such vehicles also often come with electric tools that rely on the battery when the main engine is off - such tools may be various winches, pumps, fans, and similar.

Group 22NF batteries are also often used as starting batteries for power generators, small marine gas engines and similar.

BCI Group 22NF vs. 51/51R Batteries

BCI battery groups 22NF and 51/51R feature similar dimensions (L x W x H):

- group 22NF: 9.4375 x 5.5 x 8.9375 inches (9 7/16 x 5 1/2 x 8 15/16 inches, 240 x 140 x 227 mm)

- group 51/51R: 9.374 x 5.0625 x 8.8125 inches (9 3/8 x 5 1/16 x 8 13/16, 238 x 129 x 223 mm).

As one can see, group 51/51R batteries are somewhat smaller than group 22NF batteries and any compartment that can accept group 22NF battery can accept group 51/51R battery as well.

The following chart lists some of the most popular 51/51R batteries and their most important features and specifications:

Model Battery Type Cell Type Ah CCA MCA RC Weight (lbs/kg)
ACDelco ACDB24R Dual Purpose AGM 45 325 390 70 29.11 lbs; 13.2 kg
Deka/East Penn 8AMU1R Starting AGM - 320 400 45 25 lbs; 11.3 kg
Delphi BU9051P MaxStart Dual Purpose AGM 46 325 390 60 29.5 lbs; 13.4 kg
Optima 8071-167 D51 Dual Purpose AGM 38 450 575 66 26 lbs; 11.8 kg
Optima 8073-167 D51R Dual Purpose AGM 38 450 575 66 26 lbs; 11.8 kg
VMAXTANKS SLR60 Deep Cycle AGM 60 - - 135* 43 lbs; 19.5 kg
XS Power D5100 XS Dual Purpose AGM 60 - 745 100* 39.6 lbs; 18.0 kg
XS Power D5100R XS Dual Purpose AGM 60 - 745 100* 39.6 lbs; 18.0 kg

Note: Amazon links ('Model' column) open in the new windows, feel free to check them for the most up-to-date offers and prices.

As one can see, group 51/51R batteries are not only smaller, but they also feature smaller capacity, smaller weight, and shorter Reserve Capacity.

But, they are also more suitable as starting batteries than deep-cycle group 22NF batteries.

Note: VMAXTANKS SLR60, XS Power D5100 XS, and XS Power D5100R XS are often labeled as group 51/51R batteries, but they are actually group 22NF batteries - hence the "*" in the table.

xs power d5100 xs


Long Story Short: BCI Group 22NF batteries are very popular, general-purpose batteries, offering good capacity and other discharge characteristics at an acceptable price.

Model Battery Type Cell Type Ah CCA MCA RC Weight (lbs/kg)
Absolute UX12550 Dual Purpose AGM 55 493 641 90 40.1 lbs; 17.5 kg
AJC 12V55Ah Deep Cycle AGM 55 - - - 40.1 lbs; 17.5 kg
Casil CA12550 Deep Cycle AGM 55 - - - 35 lbs; 15.9 kg
ExpertPower EXP12500 Deep Cycle AGM 55 - - - 36.0 lbs; 16.3 kg
ExpertPower EXP55-Gel Deep Cycle Gel-Cell 55 - - - 37.0 lbs; 16.8 kg
Interstate DCM0055 Deep Cycle AGM 55 - - - 37.5 lbs; 17.0 kg
Mighty Max ML55-12 Deep Cycle AGM 58 - - - 37.0 lbs; 16.8 kg
Mighty Max ML5512LI Deep Cycle LiFePO4 55 - - ~130 19.0 lbs; 8.6 kg
MK 22NF Deep Cycle AGM 51 - - - 37.0 lbs; 16.8 kg
PowerSonic PS-12550 Deep Cycle AGM 55 - - - 36.0 lbs; 16.3 kg
SigmasTek SP12-55 Deep Cycle AGM 55 - - - 36.0 lbs; 16.3 kg
SigmasTek SPG12-55 Deep Cycle Gel-Cell 51 - - - 36.6 lbs; 16.6 kg
UPG UB12550 AGM Deep Cycle AGM 55 - - - 45 lbs; 20.4 kg
UPG UB12550 Gel Deep Cycle Gel-Cell 55 - - - 38.6 lbs; 17.5 kg
UPS 12V55Ah Deep Cycle AGM 55 - - - 39.7 lbs; 18 kg
VMAXTANKS LFP22-1255 Deep Cycle LiFePO4 55 - - 120+ 15.5 lbs; 7.1 kg
VMAXTANKS MB96-60 Deep Cycle AGM 60 - - 125 43 lbs; 19.5 kg
VMAXTANKS SLR60 Deep Cycle AGM 60 - - 135 43 lbs; 19.5 kg
Weize LFP1255 Deep Cycle AGM 55/10h - - - 34.2 lbs; 15.5 kg
XS Power D5100 XS Dual Purpose AGM 60 - 745 131 43.2 lbs; 19.6 kg
XS Power D5100R XS Dual Purpose AGM 60 - 745 131 43.2; 19.6 kg

Note: Amazon links ('Model' column) open in the new windows, feel free to check them for the most up-to-date offers and prices.

When used in cyclic applications, their number of charging/discharging cycles may be increased by not discharging them below 50% or at least not below 80%.

People who have the need for lightweight group 22NF batteries that are able to cycle a lot should check lithium 22NF batteries - they are not as common as lead-acid 22NF batteries, but they are becoming more and more popular.

Amazon Search:

- 22NF Battery

- 12V 55Ah Battery

- 10 Amps AGM Battery Charger

Note: Amazon links open in the new windows, feel free to check them for the most up-to-date offers and prices.