Can I discharge a LiFePO4 battery to 0%?

Technically yes, but it is not ideal for longevity. Most LiFePO4 batteries include a BMS (battery management system) that cuts off at 2.5V per cell to prevent damage. Regularly discharging to 100% DoD shortens cycle life compared to 80% DoD — from perhaps 3,500 cycles down to 2,000 cycles . For daily-use systems like solar storage, 80% DoD offers the best balance between usable capacity and lifespan.

Do LiFePO4 batteries work in freezing temperatures?

LiFePO4 batteries discharge well in cold conditions, delivering roughly 80% capacity at 0C (32F) and 60-70% at -20C (-4F). Charging below 0C, though, can permanently damage lithium cells by causing lithium plating on the anode. Quality batteries include a BMS that blocks charging below freezing. If you use LiFePO4 in winter, either insulate and heat the battery compartment or choose a model with built-in low-temperature charging protection.

Why are LiFePO4 batteries so much more expensive upfront?

As of early 2026, a 100Ah LiFePO4 battery costs $300-600 compared to $150-250 for an equivalent AGM. But cost-per-cycle tells the real story. A $400 LiFePO4 lasting 3,000 cycles costs about $0.13 per cycle. A $200 AGM lasting 400 cycles costs $0.50 per cycle — nearly 4x more expensive over its lifetime. LiFePO4 also weighs less and wastes less energy to heat, which further tips the economics.

LiFePO4 Battery Runtime Calc — Free

4 min read

LiFePO4 (lithium iron phosphate) batteries deliver more usable energy per amp-hour than any lead-acid type. This calculator uses LiFePO4-specific defaults for depth of discharge and efficiency, giving you a realistic runtime estimate without the guesswork. For the formula breakdown and more worked examples, see our battery runtime guide.

LiFePO4 battery key specs showing 3.2V cell voltage, 95 percent usable capacity, and cycle life.

LiFePO4 vs Other Battery Chemistries

Specification	LiFePO4	AGM Lead-Acid	Flooded Lead-Acid	Lithium-Ion (NMC)
Usable DoD	80-100%	50%	50%	80-90%
Cycle Life	2,000-5,000	300-500	300-700	500-1,000
Round-trip Efficiency	92-98%	80-85%	75-85%	85-95%
Weight per kWh	~7 kg	~25 kg	~30 kg	~6 kg
Self-discharge/month	2-3%	3-5%	5-15%	3-5%
Thermal Runaway Risk	Very low	None (but gassing risk)	None (but gassing risk)	Moderate

The usable capacity gap is the key difference. A 100Ah LiFePO4 battery at 80% DoD delivers 80Ah of usable power. A 100Ah AGM at its safe 50% DoD delivers just 50Ah — 37.5% less usable energy from the same amp-hour rating.

LiFePO4 discharge curve showing flat 3.2V per cell across 90% of usable capacity. — The flat voltage plateau means a LiFePO4 battery delivers consistent power from 10% to 90% state of charge.

The LiFePO4 Voltage Curve Advantage

LiFePO4 cells hold a remarkably flat voltage throughout discharge. A single cell stays between 3.2V and 3.3V from 10% to 90% state of charge. This flat curve means your 12V system delivers nearly constant power whether the battery is nearly full or nearly empty.

Compare that to lead-acid, where a 12V battery drops from 12.7V at full to 11.8V at 50% discharge. That voltage sag reduces the effective wattage available to your devices and makes some sensitive electronics behave erratically.

The practical impact: a LiFePO4-powered inverter maintains consistent AC output right up until the BMS cuts off, while a lead-acid system gradually loses capacity as voltage drops. For devices with minimum voltage requirements — like 12V compressor fridges — LiFePO4 delivers noticeably longer effective runtimes than the raw numbers suggest.

Worked Examples

Upgrading from Lead-Acid to LiFePO4 in an RV

Context

You currently run two 100Ah lead-acid batteries (200Ah) at 50% DoD, giving you 1,056 Wh usable. You want to switch to a single 200Ah LiFePO4 at 80% DoD. Your load is 150W.

Calculation

Lead-acid usable: 200 x 12 x 0.50 x 0.88 = 1,056 Wh → runtime = 7.0 hrs

LiFePO4 usable: 200 x 12 x 0.80 x 0.92 = 1,766 Wh → runtime = 11.8 hrs

Interpretation

The LiFePO4 gives 67% more runtime from the same amp-hour capacity. That is 4.8 extra hours from one battery weighing half as much as the two lead-acid units it replaces.

Takeaway

LiFePO4 wins on usable capacity, weight, and cycle life. To see how fast solar can recharge it, use our solar battery charge time calculator.

Sizing a 48V LiFePO4 Bank for Off-Grid Solar

Context

Your cabin draws 1,500W average for 6 hours per evening (9 kWh). You want one night of autonomy from a 48V LiFePO4 bank at 80% DoD and 90% inverter efficiency.

Calculation

Energy needed: 9,000 Wh / 0.90 eff = 10,000 Wh from battery

At 48V and 80% DoD: 10,000 / (48 x 0.80) = 260.4 Ah minimum

Standard option: 3 x 100Ah 48V modules in parallel (300Ah).

Interpretation

300Ah at 48V gives 11,520 Wh usable — about 28% headroom above the 9 kWh requirement. That margin covers colder nights when battery capacity drops.

Takeaway

After sizing the bank, size the solar array to replenish it daily. Our solar panel and battery sizing calculator handles both sides in one step.

Frequently Asked Questions

Glossary

Lithium Iron Phosphate

A lithium battery chemistry (LiFePO4) known for exceptional safety, long cycle life (3,000-5,000 cycles), and flat discharge voltage. It is heavier per kWh than other lithium chemistries but does not suffer thermal runaway.

Battery Management System

An electronic circuit built into LiFePO4 batteries that monitors voltage, current, and temperature of each cell. It prevents overcharging, over-discharging, and short circuits. Without a BMS, individual cells can become dangerously unbalanced.

Flat Discharge Curve

LiFePO4 batteries maintain a nearly constant voltage (around 13.2V for a 12V battery) through most of the discharge cycle. This means your devices receive stable power from full charge down to 80% DoD, unlike lead-acid which sags progressively.

Sizing a solar system for your LiFePO4 battery bank? Our <a href="/solar/solar-battery-bank-size-calculator">solar battery bank size calculator</a> helps you match panels to storage.

LiFePO4 dominates the off-grid and mobile power space for good reason. Higher usable capacity, longer cycle life, and flat voltage output make it the best chemistry for most applications — provided you can handle the upfront cost. Run your numbers above, then check whether the cost-per-cycle math works for your use case. For a side-by-side chemistry breakdown, read our LiFePO4 vs lead-acid runtime comparison. If AGM is on your shortlist, the AGM runtime calculator uses AGM-specific defaults. And for applications needing heavy cycling on a budget, check the deep cycle runtime calculator which covers flooded and gel types too.

Last updated: March 18, 2026

Written and maintained by Dan Dadovic, Commercial Director at Ezoic Inc. & PhD Candidate in Information Sciences. He works professionally as Commercial Director at Ezoic Inc., leading revenue strategy across digital publishing.

Disclaimer: Calculator results are estimates based on theoretical formulas. Actual performance varies with temperature, battery age, load patterns, and equipment condition. For critical electrical work, consult a licensed electrician.