What Is a LiFePO4 Battery? Lithium Iron Phosphate Explained (2026 Guide)

Short answer: A LiFePO4 battery is a rechargeable lithium battery that uses lithium iron phosphate as its cathode. It runs at 3.2V per cell, so four cells make a 12.8V battery, and it lasts thousands of cycles with nearly all of its rated capacity usable. The Pro-Guide 24M100 is a typical example: 12.8V, 100Ah and 1,280Wh in a 23.8 lb Group 24 case, rated for more than 3,000 cycles at 100% depth of discharge.

LiFePO4 (say "lithium iron phosphate," or "LFP" for short) has become the standard chemistry for boats, RVs, solar storage and golf carts. This guide covers the chemistry, cycle life, pack voltages, charging and sizing, then compares the full Pro-Guide LiFePO4 lineup.

Key Takeaways

• LiFePO4 is a type of lithium-ion battery: it uses lithium iron phosphate in place of the nickel and cobalt cathodes found in many phone and laptop cells.
• Each cell is 3.2V nominal: 4 cells in series make 12.8V, 8 make 25.6V, 12 make 38.4V and 16 make 51.2V.
• Cycle life is measured in thousands: the Pro-Guide 24M100 is rated for more than 3,000 cycles at 100% depth of discharge and more than 6,000 at 80%.
• Nearly all the capacity is usable: lead-acid and AGM batteries are usually discharged only about halfway to protect their life.
• Size by watt-hours: Wh = V x Ah. A 12.8V 100Ah battery stores 1,280Wh, and a 12V 400Ah bank stores about 5,120Wh.
• Charge with a LiFePO4 profile: about 3.6V to 3.65V per cell, which is 14.6V for a 12.8V battery and 57.6V for a 51.2V pack.

What Is a LiFePO4 Battery?

LiFePO4 is the chemical formula for lithium iron phosphate. In a LiFePO4 battery, lithium ions move between a graphite anode and an iron phosphate cathode as the battery charges and discharges. The iron phosphate structure holds together well under heat and abuse, which is why this chemistry is known for stability and long life.

A finished battery combines 3.2V cells, a battery management system (BMS) that protects them, and a case, often a standard group size like Group 24 or Group 31 so it drops into the tray a lead-acid battery used. Many Pro-Guide models add Bluetooth monitoring, built-in heating and NMEA 2000 compatibility. Our guide to what NMEA is and why it matters explains that last feature.

LiFePO4 vs. Lithium-Ion and Lead-Acid

"Lithium-ion" covers several chemistries. The one most people picture is NMC (lithium nickel manganese cobalt oxide), used in many power tools and electric cars. LiFePO4 trades a little energy density for more stability and longer cycle life. Compared with lead-acid and AGM, the gap is bigger: less weight, more usable capacity and far more cycles.

Trait	LiFePO4 (LFP)	Lithium-ion NMC	Lead-acid / AGM
Nominal cell voltage	3.2V	About 3.6V to 3.7V	2V
Thermal and chemical stability	Very stable cathode	Less stable, more heat-sensitive	Stable, but can vent gas when overcharged
Usable capacity	Nearly all of the rating	Most of the rating	Usually about half, to protect battery life
Cycle life	Thousands (Pro-Guide: more than 3,000 at 100% DOD)	Generally fewer than LiFePO4	Usually hundreds
Weight for the same usable energy	Light	Lightest	Heaviest
Voltage under load	Flat until nearly empty	Gradual decline	Sags steadily as it drains
Maintenance	None	None	Flooded types need watering

The flat voltage curve matters as much as the weight: a trolling motor or golf cart on LiFePO4 holds its speed as the battery drains.

Two Pro-Guide LiFePO4 designs side by side: the 31M235-DP dual purpose battery and three Group 24 deep cycle 24M100 batteries.

Cycle Life and Depth of Discharge

Cycle count (or cycle life) is the number of full charge and discharge cycles a battery is rated to deliver before its capacity falls to a set level. Depth of discharge (DOD) is how much of the capacity you use in each cycle. Running a 100Ah battery down to 20Ah left is 80% DOD.

Shallower cycles mean more of them. The 24M100, 31M180-DP, 24VM90, 36VM75 and 48VM60 are rated for more than 3,000 cycles at 100% DOD and more than 6,000 at 80%. The PGLM10, PGLM35 and PGLM46 are rated for more than 3,000 cycles at 80% DOD, and Pro-Guide golf packs for more than 3,500 cycles.

As arithmetic only: 3,000 cycles at one full cycle per day is about 8 years of daily use. Real life depends on temperature, charge rate and how deeply you discharge.

Cell Voltage: How 12V to 48V Packs Are Built

Every LiFePO4 cell has a nominal voltage of 3.2V. Cells wired in series add voltage. Cells wired in parallel add capacity (Ah) at the same voltage. Packs are labeled by system class and by true nominal voltage.

• 12V class: 4 cells x 3.2V = 12.8V nominal
• 16V class: 5 cells x 3.2V = 16V nominal
• 24V class: 8 cells x 3.2V = 25.6V nominal
• 36V class: 12 cells x 3.2V = 38.4V nominal
• 48V class: 16 cells x 3.2V = 51.2V nominal

That is why a Pro-Guide 24VM90 is listed at 25.6V and a G48V105 golf pack at 51.2V. A single 24V, 36V or 48V battery replaces two, three or four 12V batteries wired in series, with one case and one BMS. If you are weighing those two approaches for a trolling motor, read One Pack or Three? Choosing the Right Trolling Motor Battery Setup.

What the BMS Does

The BMS measures cell voltages, current and temperature, and disconnects the battery when something goes out of range. The PGLM50, PGLM24 and 16VM50 data sheets list protection against:

• Over-charge
• Over-discharge: cuts the load before cells drain too low. The 31M180-DP, for example, has a 10V discharge cut-off.
• Over-current: which is why each model has a continuous discharge rating.
• Over-temperature
• Short circuit
• Cell balancing: keeps all cells at the same state of charge so the pack ages evenly.

The 24VM115, for example, uses a 150A BMS and is rated for 100A continuous.

How to Charge a LiFePO4 Battery

LiFePO4 charges in two simple stages: constant current until the battery reaches its charge voltage, then a short constant-voltage stage as the current tapers off. There is no long absorption stage, and no need for equalizing or desulfation modes, which are lead-acid functions. Use a charger with a LiFePO4 profile. Pro-Guide sells chargers and lists lithium-compatible gear.

Charge cut-off voltages from Pro-Guide data sheets work out to about 3.6V to 3.65V per cell:

• 12.8V: 14.6V on the 24M100 and 24M100-ST (the 31M180-DP and 31M235-DP use 14.4V)
• 16V: 18V on the 16VM160 and 18.25V on the 16VM50
• 25.6V (24V): 28.8V on the 24VM90 and 24VM115
• 38.4V (36V): 43.2V on the 36VM60, 36VM75 and G36V105
• 51.2V (48V): 57.6V on the 48VM60 and every 48V golf pack

Temperature matters. A LiFePO4 battery should not be charged below freezing unless it has a way to warm its cells. Several Pro-Guide models have built-in heating and list a charging range of -4°F to 131°F (-20°C to 55°C): the 31M180-DP, 31M235-DP, 16VM160, 24VM90, 24VM115, 36VM60, 36VM75 and 48VM60. Pro-Guide golf packs and the 16VM50 should be charged between 32°F and 131°F (0°C to 55°C). Discharging in the cold is fine within each model's rated range.

Partial charging does no harm, so you can top up when it is convenient.

Do You Need 100Ah, 200Ah or 400Ah?

Start with watt-hours, because they let you compare batteries of any voltage: Wh = nominal volts x amp-hours.

• 12.8V 100Ah = 1,280Wh
• 12.8V 150Ah = 1,920Wh
• 12.8V 200Ah = 2,560Wh
• 12.8V 400Ah = 5,120Wh

Next, add up your daily use in amp-hours (amps x hours) and add a margin of about 20%. Here is a worked example for a small RV or boat cabin. The loads are illustrative, not measured:

• 12V fridge averaging 4A for 24 hours = 96Ah
• LED lights at 3A for 5 hours = 15Ah
• Fan, water pump and phone charging at 3A for 6 hours = 18Ah
• Total = 129Ah, plus 20% margin = about 155Ah per day

Here 100Ah is too small, 150Ah is just enough and 180Ah to 200Ah gives a buffer. Double the loads, or plan two days without charging, and you need about 300Ah to 400Ah.

How that maps to Pro-Guide 12V options:

• About 100Ah: the 24M100, 1,280Wh in a Group 24 case (currently on pre-order). See our Group 24 lithium battery guide.
• 150Ah to 200Ah: the 31M180-DP, 180Ah and 2,304Wh in a standard Group 31 case. See our Group 31 dual purpose lithium guide.
• About 235Ah: the 31M235-DP, 3,008Wh in a Group 31 Tall case. See our 12V 235Ah lithium guide.

For 400Ah-class energy, look at stored watt-hours rather than a single 12V battery. A 12V 400Ah bank stores about 5,120Wh, close to the 5,376Wh in one Pro-Guide G48V105 pack. Larger 12V banks use several batteries, and 24V or 48V systems cut current and cable size for the same energy. Call Pro-Guide before wiring any batteries together so the bank matches each model's ratings.

Pro-Guide LiFePO4 Batteries by Voltage

Every model below is a LiFePO4 battery. Continuous discharge is the current the battery can deliver without stopping. "Not listed" means the data sheet does not give a continuous figure.

Model	Voltage (nominal)	Capacity	Energy	Case	Continuous discharge
PGLM10	12V	10Ah	128Wh	Compact, F2 terminals	Not listed
PGLM24	12.8V	24Ah	307.2Wh	Compact, 3 in wide	30A max
PGLM35	12V	35Ah	448Wh	Group U1	Not listed
PGLM46	12V	46Ah	588Wh	Group U1	Not listed
PGLM50	12.8V	50Ah	640Wh	Compact	50A max
24M100	12.8V	100Ah	1,280Wh	Group 24	100A
24M100-ST (starting)	12.8V	100Ah	1,280Wh	Group 24	100A
31M180-DP	12.8V	180Ah	2,304Wh	Group 31	180A
31M235-DP	12.8V	235Ah	3,008Wh	Group 31 Tall	200A
16VM50	16V	50Ah	800Wh	Compact	50A max
16VM160	16V	160Ah	2,560Wh	Group 31 Tall	100A
24VM90	25.6V	90Ah	2,304Wh	Group 31	90A
24VM115	25.6V	115Ah	2,944Wh	Group 31 Tall	100A
36VM60	38.4V	60Ah	2,304Wh	Group 31	60A
36VM75	38.4V	75Ah	2,880Wh	Group 31 Tall	75A
G36V105 (golf kit)	38.4V	105Ah	4,032Wh	Metal golf pack	200A
48VM32	48V	32Ah	1,536Wh	GC2	Not listed
48VM60	51.2V	60Ah	3,072Wh	Group 31 Tall	60A
G48V105 (golf kit)	51.2V	105Ah	5,376Wh	Metal golf pack	200A
G48V150 (golf kit)	51.2V	150Ah	7,680Wh	Metal golf pack	300A
G48V210 (golf kit)	51.2V	210Ah	10,752Wh	Metal golf pack	300A

Pro-Guide also offers the G48V105M, with the same 51.2V, 105Ah and 200A ratings as the G48V105 in a smaller footprint, and the 70.4V G72V105 for 72V carts. Browse by voltage in the 12V, 24V, 36V and 48V collections.

Where Each Battery Fits

Marine

For trolling motors, the 36VM60 and 36VM75 put a 36V supply in one case, and the 24VM90 and 24VM115 serve 24V systems. The 31M180-DP and 31M235-DP crank at 1,000 CCA (lead-acid equivalent) and run electronics from one battery. Kayaks and fish finders suit the PGLM series, and 16V-compatible electronics suit the 16VM50 and 16VM160. Shop trolling motor batteries or a marine power kit.

RV and overlanding

The 31M180-DP and 31M235-DP give a 12V house bank 2,304Wh or 3,008Wh from one battery, with built-in heating for cold-weather charging. Systems built on 24V can use the 24VM90 or 24VM115.

Solar and off-grid storage

The 48VM32 stores 1,536Wh in a GC2 case for 48V solar systems. The 24VM115 is built for 24V off-grid systems, with 2,944Wh in one Group 31 Tall case.

Golf carts and LSEVs

The G36V105, G48V105, G48V105M, G48V150, G48V210 and G72V105 are sold as kits with a matched charger, state of charge gauge and 12V converter. The 48VM60 suits low-speed electric vehicles and utility machines within its 60A rating. Compare them in our best lithium battery for golf carts guide or shop golf cart batteries.

A 51.2V G48V105 golf pack: 16 LiFePO4 cells in series, 5,376Wh, in one case under the seat.

Frequently Asked Questions

What is a LiFePO4 battery?

A LiFePO4 battery is a rechargeable lithium battery with a lithium iron phosphate cathode. Each cell is 3.2V nominal, so four cells in series make a 12.8V battery. It is known for stability, long cycle life and nearly full usable capacity.

Is LiFePO4 the same as lithium-ion?

LiFePO4 is one type of lithium-ion battery. It uses iron phosphate instead of the nickel, manganese and cobalt cathode in NMC cells, which makes it more thermally stable and longer lasting, with slightly lower energy density.

How many cycles does a LiFePO4 battery last?

Ratings vary by model. The Pro-Guide 24M100 is rated for more than 3,000 cycles at 100% depth of discharge and more than 6,000 at 80%. Pro-Guide lithium golf packs are rated for more than 3,500 cycles.

What voltage do you charge a 12V LiFePO4 battery to?

Most 12.8V LiFePO4 batteries charge to about 14.4V to 14.6V. The Pro-Guide 24M100 has a 14.6V charge cut-off. A 25.6V battery charges to 28.8V, a 38.4V battery to 43.2V and a 51.2V battery to 57.6V.

Can you charge a LiFePO4 battery below freezing?

Not without heating. Pro-Guide models with built-in heating, such as the 24VM90, 36VM75 and 31M180-DP, list a charging range of -4°F to 131°F. Pro-Guide golf packs list a charging range of 32°F to 131°F, so charge them only above freezing.

Do I need a 100Ah, 200Ah or 400Ah lithium battery?

Add up your daily amp-hours and add about 20%. A 12.8V 100Ah battery stores 1,280Wh, 200Ah stores 2,560Wh and 400Ah stores 5,120Wh. Pro-Guide offers 12V options at 100Ah, 180Ah and 235Ah, and 48V packs up to 10,752Wh.

How long will a 150Ah lithium battery last?

Divide 150Ah by your load in amps. On a steady 10A load, a 150Ah battery runs about 15 hours. At 12.8V it stores about 1,920Wh. Real runtime depends on load, temperature and depth of discharge.

Can I use a lead-acid charger on a LiFePO4 battery?

Use a charger with a LiFePO4 profile. Lead-acid chargers can use the wrong voltages and add equalize or desulfation modes that do not suit lithium. Pro-Guide golf kits include a matched lithium charger.

Shop Pro-Guide LiFePO4 Batteries

A LiFePO4 battery gives you thousands of cycles, nearly all of its rated capacity and a fraction of the weight of lead-acid. Pick the voltage your system runs on, size it in watt-hours, then match the case and continuous discharge rating to your space and your load. Pro-Guide offers LiFePO4 batteries from 10Ah fish finder batteries to 10,752Wh golf packs.

SHOP PRO-GUIDE LITHIUM BATTERIES

Need deep cycle power for a boat or RV? Browse every Pro-Guide deep cycle lithium battery or call our team at 1-800-827-3232 for help choosing the right battery.

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