---
title: "How does a LiFePO4 cell differ from a LiPo?"
topic: "LiPo vs LiFePO4"
answer: "A LiFePO4 cell, or LiFe, holds less energy for its weight, lasts longer and fails more gently, but its flat voltage hides how full it is. Read with the same 10 mV error, a half-full LiPo could be 47 to 53% and a half-full LiFe anywhere from 42 to 71%. So a LiFe needs a gauge that counts charge and a charger set for 3.60 V a cell."
url: "https://nearfieldnotes.com/notes/lipo-vs-life/"
site: "Near Field Notes"
author: "Michael Walker"
note: 18
family: "Power"
published: "2026-11-06"
revised: "2026-11-06"
revision: 1
video: "https://nearfieldnotes.com/videos/lipo-vs-life/"
---

Note 18 · [Power](https://nearfieldnotes.com/families/power/) · Rev 1 · [Watch the video · 3:04](https://nearfieldnotes.com/videos/lipo-vs-life/)

LiPo vs LiFePO4

# How does a LiFePO4 cell differ from a LiPo?

**Short answer:** A LiFePO4 cell, or LiFe, holds less energy for its weight, lasts longer and fails more gently, but its flat voltage hides how full it is. Read with the same 10 mV error, a half-full LiPo could be 47 to 53% and a half-full LiFe anywhere from 42 to 71%. So a LiFe needs a gauge that counts charge and a charger set for 3.60 V a cell.

The figure reads each half-full cell with a meter that is up to 10 mV off, first low, then high.

**Note 18’s opening figure: Two half-full cells.** The same 10 mV error on each

![Note 18’s opening figure: Two half-full cells](https://nearfieldnotes.com/notes/lipo-vs-life/fig-opening.png)

*What the figure shows:* Two charts, one per cell, of rest voltage against charge from 35 to 75%, drawn to the same millivolt scale. Each cell is half full. A meter reading 10 mV either side of the true voltage fits a LiPo charge of 47–53%, around 3.790 V, and a LiFe charge of 42–71%, around 3.264 V. The LiPo's curve climbs through the window. The LiFe's is almost flat.

Each chart is one cell at rest, both drawn to the same scale. The dashed lines sit 10 mV either side of the true voltage. The bar under each chart spans every charge that fits between them.

**The numbers**

| Cell | True charge | At rest | Reading | Charges that fit |
|---|---|---|---|---|
| LiPo | 50% | 3.790 V | 3.780 to 3.800 V | 47–53% |
| LiFe | 50% | 3.264 V | 3.254 to 3.274 V | 42–71% |

## A LiPo cell and a LiFe cell

*What differs inside*

A LiPo is a lithium cobalt oxide cell in a soft foil pouch, like the cells in a hobby pack. It is full at 4.20 V and averages 3.7 V.

The LiFe here is A123’s ANR26650M1, a metal can 26 mm across and 65 mm long. It is full at 3.60 V and averages 3.3 V.

**Fig. 18: The two cells.**

![Fig. 18: The two cells](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18.png)

*What the figure shows:* Figure 18: the two cells standing side by side, rendered at one scale. Left, a hobby LiPo pouch cell, silver, with an aluminum tab and a nickel tab at its top. Right, an A123 26650 LiFePO4 cell, 26 × 65 mm, a metal can in a lime sleeve with a metal cap on top.

At one scale. Their models hold about the same charge, 2.28 and 2.3 Ah.

**The numbers**

| Cell | Cathode | Capacity | Full | Nominal | Empty |
|---|---|---|---|---|---|
| LiPo | LiCoO₂ | 2.28 Ah | 4.20 V | 3.7 V | 3.0 V |
| LiFe | LiFePO₄ | 2.3 Ah | 3.60 V | 3.3 V | 2.0 V |

Inside, both have the same anode: graphite on copper foil. Charging pulls lithium out of the cathode and packs it between the graphite’s layers.

The cathodes differ. A full LiCoO₂ cathode still holds half its lithium. A full LiFePO₄ cathode holds none, so it has nothing left to give if a charger keeps pushing.

**Fig. 18b: Inside, full.**

![Fig. 18b: Inside, full](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18b.png)

*What the figure shows:* Figure 18b: a sketch of each cell's layers when full. Both have a copper foil coated with graphite, then a separator, then the cathode on an aluminum foil. Lithium, drawn as gold dots, sits between the graphite's layers. The LiPo's cathode is layered LiCoO2 and still holds lithium in half its sites; the LiFe's is LiFePO4 and holds none. The LiPo is full at 4.20 V, the LiFe at 3.60 V.

A sketch, not to scale. Gold dots are lithium. Small open dots are empty places for it in the cathode.

**The numbers**

| Cell | Anode | Cathode | Lithium left in the cathode when full | Full at |
|---|---|---|---|---|
| LiPo | Graphite | LiCoO₂, layered | Half | 4.20 V |
| LiFe | Graphite | LiFePO₄, olivine | None | 3.60 V |

## Voltage against charge

*Steep against flat*

Rested, each cell’s voltage follows its charge. From 20 to 80% the LiPo climbs 299 mV.

The LiFe climbs 141 mV, from 3.17 V to 3.31 V. Most of its charge sits on a voltage that barely moves.

**Fig. 18c: Each cell at rest.**

![Fig. 18c: Each cell at rest](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18c.png)

*What the figure shows:* Figure 18c: each cell's voltage at rest against its charge. The LiPo's climbs from 3.0 V empty to 4.2 V full the whole way, from 3.69 V at 20% to 3.99 V at 80%. The LiFe's rises steeply from 2.0 V, then sits near 3.3 V: 3.17 V at 20%, 3.31 V at 80%, before it climbs to 3.6 V at full.

The dots mark 20 and 80% on each curve.

**The numbers**

| Charge | LiPo at rest | LiFe at rest |
|---|---|---|
| 0% | 3.000 V | 2.000 V |
| 10% | 3.636 V | 2.975 V |
| 20% | 3.692 V | 3.166 V |
| 30% | 3.730 V | 3.203 V |
| 40% | 3.759 V | 3.250 V |
| 50% | 3.790 V | 3.264 V |
| 60% | 3.833 V | 3.267 V |
| 70% | 3.906 V | 3.272 V |
| 80% | 3.991 V | 3.307 V |
| 90% | 4.084 V | 3.312 V |
| 100% | 4.197 V | 3.598 V |

So a meter’s error becomes a charge error, divided by how steeply the curve climbs:

`Δq ≈ ΔV/s`

where Δq: charge error (%); ΔV: meter error (mV); s: slope of the rest curve (mV per %).

`LiPo: (10 mV)/(3.6 mV/%) = 2.8%`

`LiFe: (10 mV)/(0.58 mV/%) = 17%`

Those slopes are at half full. The LiFe’s changes along the way, so its range in the opening figure is lopsided: 8 points below half and 21 above.

## Charging

*1C from 10%*

Both charge the same way. A [constant current](https://nearfieldnotes.com/glossary/#g-cc-cv) runs until the cell reaches its full voltage. Then the charger holds that voltage while the current tapers to a twentieth.

The LiPo reaches 4.20 V at 48 min and holds it for 31 min. The LiFe stays flat almost to the end, then climbs from 3.5 to 3.6 V in 27 s. It holds 3.60 V for only 2.5 min.

That last climb is all the warning a LiFe gives that it is full.

**Fig. 18d: A 1C charge.**

![Fig. 18d: A 1C charge](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18d.png)

*What the figure shows:* Figure 18d: both cells charged at 1C from 10%. Each takes a constant current until it reaches its full voltage, then holds that voltage while the current tapers to a twentieth. The LiPo reaches 4.20 V after 48 minutes and holds it for 31 minutes, 79 in all. The LiFe stays near 3.3 to 3.4 V, reaches 3.60 V after 53 minutes and holds it for 2.5, 56 in all.

Each cell from 10%, at 25 °C. Each line ends when the current falls to a twentieth.

**The numbers**

| Cell | Holds | Reaches it at | Then holds it for | Done at | Charge taken |
|---|---|---|---|---|---|
| LiPo | 4.20 V | 48 min | 30.8 min | 79 min | 2.20 Ah |
| LiFe | 3.60 V | 53 min | 2.5 min | 56 min | 2.07 Ah |

## The wrong setting

*LiPo and LiFe on one charger*

Hobby chargers charge both, and you pick the chemistry from a menu. On the LiPo setting, a charger aims for 4.20 V a cell. A LiFe is full at 3.60.

In the model, a LiFe on the LiPo setting goes from 3.60 to 4.20 V in 33 s, taking only 21 mAh more. Its cathode has no lithium left to give. In overcharge tests, a LiFe starts heating up at 100% of full, a LiCoO₂ cell only near 150%.

**Fig. 18e: A LiFe on the LiPo setting.**

![Fig. 18e: A LiFe on the LiPo setting](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18e.png)

*What the figure shows:* Figure 18e: a LiFe cell charged at 1C on a charger set for a LiPo. Its voltage creeps up toward 3.60 V, full, then climbs to the charger's 4.20 V in 33 seconds, taking 21 mAh more.

1C from 90%. The run stops where the cell reaches the charger’s 4.20 V.

**The numbers**

| Seconds from 3.60 V | LiFe cell |
|---|---|
| −120 | 3.410 V |
| −60 | 3.441 V |
| −30 | 3.489 V |
| −10 | 3.552 V |
| 0 | 3.601 V |
| +10 | 3.666 V |
| +20 | 3.753 V |
| +30 | 3.884 V |
| 32.7 | 4.200 V |

Overcharge

### A LiFe pushed to a LiPo’s voltage

**Field marks.** A 2S LiFe pack charging toward 8.4 V, where 7.2 V is full. The charger’s menu says LiPo.

**Look-alike.** The opposite mistake. A LiPo on the LiFe setting stops at 3.60 V a cell, nearly empty: 6% full in the model, 5 to 20% in real cells.

**Range.** Overcharged until they failed in Mao’s 2023 tests, LiFePO₄ pouch cells smoked and peaked near 310 °C. LiCoO₂ and NMC cells burned past 1000 °C. Victron’s BMS stops a charge when any cell passes 3.75 V.

**Habitat.** Hobby chargers with a battery-type menu. SkyRC’s B6 Evo offers LiPo, LiIon, LiFe, LiHV, NiCd, NiMH and Pb.

## One weak cell

*A 4S LiFe pack on a plain charger*

Four LiFe cells in series make a 12 V battery, charged to 14.4 V. Here the far cell holds 5% less than the others. A plain charger sees only the total:

`V_pack = V_1 + V_2 + V_3 + V_4`

where V_pack: pack voltage (V); V_1: cell 1’s voltage (V); V_2: cell 2’s voltage (V); V_3: cell 3’s voltage (V); V_4: cell 4’s voltage, the far cell (V).

`3.328 + 3.328 + 3.328 + 4.416 = 14.40 V`

The total is right at the end of the charge. The cells aren’t. The far cell ends at 4.42 V, the others at 3.33 V.

**Fig. 18f: The pack at the end of its charge.**

![Fig. 18f: The pack at the end of its charge](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18f.png)

*What the figure shows:* Figure 18f: four LiFe 26650 cells in a row, joined in series by nickel straps, red lead at the near cell, black at the far one. Tags give each cell's voltage at the end of a 14.4 V charge: the three full cells at 3.33 V, the far one, which holds 5% less, at 4.42 V.

Each tag is that cell’s voltage when the charger stops, after 47 min.

**The numbers**

| Cell | Holds | Ends at |
|---|---|---|
| 1 | 100% | 3.328 V |
| 2 | 100% | 3.328 V |
| 3 | 100% | 3.328 V |
| 4, the far one | 95% | 4.416 V |

For most of the charge, all four sit on the flat part, within 17 mV of each other until 43 min. Then the small cell reaches its steep end first. It passes 3.60 V at 45 min and ends past the 3.75 V where Victron’s BMS stops a charge.

The same small cell in a 3S LiPo pack ends at 4.23 V, as in [Note 15](https://nearfieldnotes.com/notes/battery-balance/), which covers balancing. A LiPo’s slope shows the gap all through the charge. A LiFe hides it until the last minutes. TI warns that this steep end of charge “can lead to significant cell-to-cell voltage divergence”.

**Fig. 18g: The pack charging.**

![Fig. 18g: The pack charging](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18g.png)

*What the figure shows:* Figure 18g: each cell's voltage while the 4S LiFe pack charges at 1C to 14.4 V, from 20%. All four sit near 3.3 V for most of the charge. The cell with 5% less stays within 17 mV of the others until 43 minutes, passes 3.60 V at 45 minutes and ends at 4.42 V after 47 minutes, while the other three end at 3.33 V. Dashed lines mark full, 3.60 V, and the 3.75 V where Victron's BMS stops a charge.

1C from 20%, until the current falls to a twentieth at 14.4 V. Purple is cells 1 to 3, which charge as one. Orange is the far cell.

**The numbers**

| Minute | Cells 1 to 3 | Cell 4 | Pack |
|---|---|---|---|
| 0 | 3.254 V | 3.257 V | 13.02 V |
| 10 | 3.337 V | 3.340 V | 13.35 V |
| 20 | 3.342 V | 3.349 V | 13.38 V |
| 30 | 3.387 V | 3.392 V | 13.55 V |
| 40 | 3.399 V | 3.407 V | 13.60 V |
| 43 | 3.405 V | 3.421 V | 13.64 V |
| 45 | 3.414 V | 3.623 V | 13.86 V |
| 47.4, end | 3.328 V | 4.416 V | 14.40 V |

## Counting charge

*When the voltage can’t say*

So a LiFe gauge [counts charge](https://nearfieldnotes.com/glossary/#g-coulomb-counting) instead. It reads the current through a shunt and adds it up, in and out.

Counting drifts. Any offset in the current reading adds up too:

`Δq_drift = I_off t/Q`

where Δq_drift: gauge drift (% of full); I_off: offset in the current reading (A); t: time since the gauge was last reset (h); Q: cell capacity (Ah).

`= (1 mA × 720 h)/(2.5 Ah) = 29%`

TI’s example offset is 1 mA. Never corrected, it walks a 2.5 Ah gauge 29% off in 30 days. Real gauges trim their offset, so this is the size of the problem, not a typical result.

A counter needs a fixed point. A full charge is one. Held at 3.60 V until the current tapers off, the cell is full whatever the count says.

Victron’s SmartShunt resets at a full charge, once the voltage passes its charged level and the current tapers. It asks for one regularly to stop the drift. Reset every 7 days, the same offset never gets past 6.7%.

**Fig. 18h: A counter’s drift.**

![Fig. 18h: A counter’s drift](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18h.png)

*What the figure shows:* Figure 18h: how far a coulomb counter's reading drifts from the truth with a 1 mA sensor offset on a 2.5 Ah cell. Never reset, the error climbs in a straight line to 29% after 30 days. Reset by a full charge every 7 days, it climbs to 6.7% and falls back to zero each time.

A 1 mA offset on a 2.5 Ah cell, the size of A123’s later ANR26650M1-B.

**The numbers**

| Day | Never reset | Full charge every 7 days |
|---|---|---|
| 0 | 0.0% | 0.0% |
| 7 | 6.7% | 6.7%, then 0 |
| 14 | 13.4% | 6.7%, then 0 |
| 21 | 20.2% | 6.7%, then 0 |
| 28 | 26.9% | 6.7%, then 0 |
| 30 | 28.8% | 1.9% |

The other fixed point is a [rested voltage](https://nearfieldnotes.com/glossary/#g-ocv), away from the flat part. TI’s gauge won’t trust one from A123’s cell between 34 and 93%, and waits 5 hours after a charge before trusting one at all. Its default wait is 30 minutes.

Even rested, a LiFe’s voltage depends on whether it was last charged or discharged. In one 20 Ah cell the gap was about 15 mV at half charge, more than the opening figure’s 10 mV error.

**Fig. 18i: Where TI ignores the voltage.**

![Fig. 18i: Where TI ignores the voltage](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18i.png)

*What the figure shows:* Figure 18i: the charge ranges where TI's Impedance Track gauge won't trust a rested cell's voltage, from TI's Table 1. LiCoO2, 3737 to 3800 mV, 26 to 54%. A123's LiFePO4, 3274 to 3351 mV, 34 to 93%.

TI’s keep-out ranges for its Impedance Track gauges. Inside a bar, a rested reading isn’t used to set the charge.

**The numbers**

| Chemistry | TI ID | Not trusted from | To | Charge |
|---|---|---|---|---|
| LiCoO₂ | 100 | 3737 mV | 3800 mV | 26 to 54% |
| LiFePO₄, A123 | 404 | 3274 mV | 3351 mV | 34 to 93% |

Coulomb counter

### Counts every coulomb, and needs a full charge to stay right

**Field marks.** A shunt in the battery’s negative lead, read by a chip that adds up the current. Victron’s SmartShunt and TI’s Impedance Track gauges work this way.

**Look-alike.** A battery bar that reads voltage alone. On a LiPo it comes close. On a LiFe, 10 mV off fits anything from 42 to 71%.

**Range.** A 1 mA offset left alone walks a 2.5 Ah gauge 29% off in a month. Maxim’s gauge, a counter mixed with a voltage model, stayed within 2% on an A123 26650 for over a week without reaching full or empty.

**Habitat.** 12 V LiFe banks in RVs, boats and solar systems, and any LiFe pack with a charge display.

## Charging in the cold

*Same graphite, same limit*

Charging pushes lithium into the graphite. In the cold it moves in slowly, and the graphite’s voltage against lithium falls. Below 0 V, lithium metal can build up on the anode’s surface instead.

Both cells use graphite, so this model is the LiPo’s. At 1C and 25 °C the graphite bottoms out at 5.6 mV. At 10 °C it spends 9 min below 0 V, at 0 °C 31 min, and at −10 °C 105 min.

Half the current at 0 °C keeps it above 0 V, at 11 mV. The charge takes 144 min instead of 104 min.

**Fig. 18j: The graphite while charging.**

![Fig. 18j: The graphite while charging](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18j.png)

*What the figure shows:* Figure 18j: the graphite electrode's voltage against lithium while a cell charges, from the LiPo cell model. Below 0 V, lithium metal can form on the graphite. 25 °C at 1C, lowest +6 mV. 10 °C at 1C, lowest -19 mV, below 0 V for 9 minutes. 0 °C at 1C, lowest -67 mV, below 0 V for 31 minutes. 0 °C, half the current, lowest +11 mV. Each line ends when its charge does.

From 10%, at 1C unless marked. The lowest point in the graphite, beside the separator. Each line ends when its charge does. The −10 °C run is in the table.

**The numbers**

| Temperature | Current | Lowest | Below 0 V for | Charge took |
|---|---|---|---|---|
| 25 °C | 1C | +5.6 mV | never | 79 min |
| 10 °C | 1C | −19.3 mV | 9.0 min | 87 min |
| 0 °C | 1C | −66.9 mV | 30.8 min | 104 min |
| −10 °C | 1C | −99.9 mV | 104.7 min | 185 min |
| 0 °C | C/2 | +10.6 mV | never | 144 min |

So both datasheets stop charging at 0 °C. The LiFe’s allows charging up to 55 °C, the LiPo’s up to 45 °C.

**Fig. 18k: Allowed temperatures.**

![Fig. 18k: Allowed temperatures](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18k.png)

*What the figure shows:* Figure 18k: the temperatures each cell's datasheet allows. LiPo charge, 0 to 45 °C. LiPo discharge, -20 to 60 °C. LiFe charge, 0 to 55 °C. LiFe discharge, -20 to 55 °C. The LiPo is Varta's PLF 523450 C, the LiFe EVE's LF280K. Neither charges below 0 °C.

Varta’s PLF 523450 C LiPo cell and EVE’s LF280K LiFe cell. Filled bars are charging, open bars discharging.

**The numbers**

| Cell | Charge | Discharge | Datasheet |
|---|---|---|---|
| LiPo | 0 to 45 °C | −20 to 60 °C | Varta PLF 523450 C |
| LiFe | 0 to 55 °C | −20 to 55 °C | EVE LF280K |

Cold charging

### Lithium metal on the anode, in either cell

**Field marks.** A charge started below 0 °C, or a fast one just above it. Outdoors, a battery that warms itself before it takes a charge.

**Look-alike.** The idea that a LiFe charges fine in the cold. Its cathode differs. Its anode is the same graphite, and the model’s 1C charge at 0 °C spends 31 min below 0 V.

**Range.** At −20 °C, Zinth’s 2014 neutron study found up to 19% of the working lithium had turned to metal. After a 20 h rest, only part of it had come back.

**Habitat.** RV, boat and solar batteries left out in winter. Battle Born’s heated batteries switch a heater on near 35 °F and off near 45 °F, powered by the battery itself.

## Heat

*Heated until they fail*

Golubkov and colleagues heated 18650 cells in argon until they failed. The LiFePO₄ cell began heating itself later, at 195 °C against 149. It peaked at 404 °C against 853, and gave off a fifth of the gas.

The reason is oxygen. Hot LiCoO₂ breaks down and gives off oxygen, which burns with the electrolyte. LiFePO₄ keeps its oxygen even when it breaks down.

Part of the gap is size. The LiFePO₄ cell held 3.5 Wh, the other about 9.9.

**Fig. 18l: Heated until they fail.**

![Fig. 18l: Heated until they fail](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18l.png)

*What the figure shows:* Figure 18l: Golubkov's 2014 tests, 18650 cells heated in argon until they failed. A LiCoO2/NMC cell began heating itself at 149 °C, peaked at 853 °C and gave off 265 mmol of gas. The LiFePO4 cell began at 195 °C, peaked at 404 °C and gave off 50 mmol.

Golubkov 2014, Table 3. The cobalt cell’s cathode is LiCoO₂ and NMC, two to one.

**The numbers**

| Measure | LiCoO₂/NMC 18650 | LiFePO₄ 18650 |
|---|---|---|
| Self-heating starts | 149 °C | 195 °C |
| Hottest point | 853 °C | 404 °C |
| Gas given off | 265 mmol | 50 mmol |

Heat still wears a LiFe out. EVE rates its LF280K for 6,000 cycles at 25 °C and 2,500 at 45 °C.

## Storage and shipping

*Neither likes sitting full*

Store a LiPo at 3.8 V a cell, about half full. Hobby chargers have a storage mode that charges or discharges a pack to it.

Store a LiFe at 30 to 50%, as EVE specifies for its LF280K.

Sitting full costs it too, and heat costs more. Keil’s A123 cells lost twice as much stored full as half full. Half full at 50 °C, they lost four times as much.

**Fig. 18m: Stored nine months.**

![Fig. 18m: Stored nine months](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18m.png)

*What the figure shows:* Figure 18m: capacity A123's LiFePO4 cells lost in nine months of storage, from Keil 2016. At 25 °C, about 3% half full and 6% full. At 50 °C half full, about 12%.

Keil 2016, A123’s LiFePO₄ 18650 cells, read from their Fig. 2c.

**The numbers**

| Stored nine months | Capacity lost |
|---|---|
| 25 °C, half full | about 3% |
| 25 °C, full | about 6% |
| 50 °C, half full | about 12% |

Shipped alone by air, both count as lithium-ion. Since 1 April 2016 they fly on cargo aircraft only, at 30% charge or less.

## The two cells

*Side by side*

**Fig. 18n: LiPo.**

![Fig. 18n: LiPo](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18n.png)

*What the figure shows:* Figure 18n: the top of a LiPo pouch cell, close in. Two flat tabs come out of the sealed foil edge: aluminum for + and nickel for −. The arrow points to the aluminum + tab.

Closer than Fig. 18. The arrow marks the aluminum + tab.

**The numbers**

| Field mark | LiPo |
|---|---|
| Case | Soft foil pouch |
| Terminals | Two flat tabs, aluminum + and nickel − |
| Full | 4.20 V |
| Nominal | 3.7 V |

LiPo

### Lighter and easy to read, hotter when it fails

**Field marks.** A soft foil pouch with two flat tabs, aluminum for + and nickel for −. Full at 4.20 V, 3.7 V nominal, empty at 3.0 V.

**Look-alike.** A hobby LiFe pack, in the same shrink wrap with the same balance plug. Its label says LiFe and 3.3 V a cell.

**Range.** A Gens Ace 2200 mAh 3S pack stores 145 Wh/kg. Rated for 150 to 500 cycles. Charges at 0 to 45 °C. Heated until it failed, an LCO/NMC 18650 peaked at 853 °C. Stored at 3.8 V a cell.

**Habitat.** Drones, RC cars and planes, where every gram counts.

**Fig. 18o: LiFe.**

![Fig. 18o: LiFe](https://nearfieldnotes.com/notes/lipo-vs-life/fig-18o.png)

*What the figure shows:* Figure 18o: the top half of an A123 26650 LiFePO4 cell, close in. A metal cap sits in a white ring on top, and LiFePO4 is printed down the lime sleeve. One arrow points to the cap, one to the printing. On this cell the cap is − and the can is +.

Closer than Fig. 18. The arrows mark the cap and the printing. On this cell the cap is − and the can is +.

**The numbers**

| Field mark | LiFe |
|---|---|
| Case | Metal can in a printed sleeve |
| Terminals | The cap on top is −, the can is + |
| Size | 26 × 65 mm |
| Full | 3.60 V |
| Nominal | 3.3 V |

LiFe

### Heavier and long-lived, calmer, hard to gauge

**Field marks.** A metal can or a block, printed LiFePO4 or LFP. Full at 3.60 V, 3.3 V nominal, empty at 2.0 V.

**Look-alike.** A 12 V lead-acid battery. A 4S LiFe drop-in like Battle Born’s 100 Ah fits the same space and charges at 14.4 V.

**Range.** Spektrum’s 2200 mAh 2S LiFe pack stores 110 Wh/kg. Rated for 1,000 to 6,000 cycles. Charges at 0 to 55 °C. Heated until it failed, an LFP 18650 peaked at 404 °C. Stored at 30 to 50%.

**Habitat.** RC receiver packs, and 12 V banks in RVs, boats and solar systems.

## Which cell

*A key*

Key to LiPo and LiFe

### Which cell, and what does it need?

1. 1a Every gram counts LiPo, charged to 4.20 V a cell
2. 1b Life and safety count more than weight Go to 2
3. 2a It must charge below 0 °C Either cell, with a heater
4. 2b It charges above 0 °C Go to 3
5. 3a Its charge must be read from voltage alone LiPo
6. 3b It can have a shunt and a coulomb counter LiFe, charged to 3.60 V a cell, with a BMS on every cell

Both cells share 2a: their graphite takes no charge below 0 °C.

## Read a cell yourself

*68 readings, every one drawn*

Pick how full both cells really are and how far off the meter is. The thick part of each curve, and the bar under it, is every charge that reading could mean.

The LiFe’s curve isn’t flat everywhere. Below about a third full it slopes, and a reading there is as good as a LiPo’s. TI’s keep-out range for A123’s cell starts at 34% too.

**Note 18’s explorer: Each cell, read.**

![Note 18’s explorer: Each cell, read](https://nearfieldnotes.com/notes/lipo-vs-life/fig-explore.png)

*What the figure shows:* Each cell's rest voltage against its charge, with the chosen true charge marked on both curves. The thick part of each curve, and the bar under it, cover every charge a reading that far off could mean.

The rest curves of Fig. 18c. The reading is the true rest voltage, give or take the error.

**Every case, as a table**

| True charge | Meter error | LiPo at rest | LiPo could be | LiFe at rest | LiFe could be |
|---|---|---|---|---|---|
| 10% | ±1 mV | 3.636 V | 10% | 2.975 V | 10% |
| 10% | ±5 mV | 3.636 V | 9–11% | 2.975 V | 10% |
| 10% | ±10 mV | 3.636 V | 9–12% | 2.975 V | 10% |
| 10% | ±20 mV | 3.636 V | 8–14% | 2.975 V | 9–11% |
| 15% | ±1 mV | 3.662 V | 15% | 3.105 V | 15% |
| 15% | ±5 mV | 3.662 V | 15–16% | 3.105 V | 15% |
| 15% | ±10 mV | 3.662 V | 14–16% | 3.105 V | 15% |
| 15% | ±20 mV | 3.662 V | 12–18% | 3.105 V | 14–16% |
| 20% | ±1 mV | 3.692 V | 20% | 3.166 V | 20% |
| 20% | ±5 mV | 3.692 V | 19–21% | 3.166 V | 19–21% |
| 20% | ±10 mV | 3.692 V | 18–22% | 3.166 V | 19–23% |
| 20% | ±20 mV | 3.692 V | 16–24% | 3.166 V | 18–26% |
| 25% | ±1 mV | 3.714 V | 25% | 3.183 V | 25% |
| 25% | ±5 mV | 3.714 V | 24–26% | 3.183 V | 23–26% |
| 25% | ±10 mV | 3.714 V | 22–28% | 3.183 V | 22–28% |
| 25% | ±20 mV | 3.714 V | 20–31% | 3.183 V | 20–30% |
| 30% | ±1 mV | 3.730 V | 30% | 3.203 V | 30% |
| 30% | ±5 mV | 3.730 V | 29–32% | 3.203 V | 29–31% |
| 30% | ±10 mV | 3.730 V | 27–33% | 3.203 V | 28–32% |
| 30% | ±20 mV | 3.730 V | 24–37% | 3.203 V | 25–34% |
| 35% | ±1 mV | 3.745 V | 35% | 3.230 V | 35% |
| 35% | ±5 mV | 3.745 V | 33–37% | 3.230 V | 34–36% |
| 35% | ±10 mV | 3.745 V | 32–38% | 3.230 V | 33–37% |
| 35% | ±20 mV | 3.745 V | 29–42% | 3.230 V | 31–40% |
| 40% | ±1 mV | 3.759 V | 40% | 3.250 V | 40% |
| 40% | ±5 mV | 3.759 V | 38–42% | 3.250 V | 39–42% |
| 40% | ±10 mV | 3.759 V | 36–44% | 3.250 V | 37–45% |
| 40% | ±20 mV | 3.759 V | 33–47% | 3.250 V | 35–69% |
| 45% | ±1 mV | 3.773 V | 45% | 3.260 V | 44–46% |
| 45% | ±5 mV | 3.773 V | 43–47% | 3.260 V | 42–52% |
| 45% | ±10 mV | 3.773 V | 42–48% | 3.260 V | 40–69% |
| 45% | ±20 mV | 3.773 V | 38–51% | 3.260 V | 37–73% |
| 50% | ±1 mV | 3.790 V | 50% | 3.264 V | 48–52% |
| 50% | ±5 mV | 3.790 V | 49–51% | 3.264 V | 44–67% |
| 50% | ±10 mV | 3.790 V | 47–53% | 3.264 V | 42–71% |
| 50% | ±20 mV | 3.790 V | 44–55% | 3.264 V | 38–74% |
| 55% | ±1 mV | 3.809 V | 55% | 3.266 V | 52–60% |
| 55% | ±5 mV | 3.809 V | 54–56% | 3.266 V | 46–69% |
| 55% | ±10 mV | 3.809 V | 53–57% | 3.266 V | 42–72% |
| 55% | ±20 mV | 3.809 V | 50–59% | 3.266 V | 39–74% |
| 60% | ±1 mV | 3.833 V | 60% | 3.267 V | 55–65% |
| 60% | ±5 mV | 3.833 V | 59–61% | 3.267 V | 47–70% |
| 60% | ±10 mV | 3.833 V | 58–62% | 3.267 V | 43–72% |
| 60% | ±20 mV | 3.833 V | 56–63% | 3.267 V | 39–74% |
| 65% | ±1 mV | 3.865 V | 65% | 3.268 V | 61–67% |
| 65% | ±5 mV | 3.865 V | 64–66% | 3.268 V | 48–71% |
| 65% | ±10 mV | 3.865 V | 64–66% | 3.268 V | 44–72% |
| 65% | ±20 mV | 3.865 V | 62–67% | 3.268 V | 39–75% |
| 70% | ±1 mV | 3.906 V | 70% | 3.272 V | 69–70% |
| 70% | ±5 mV | 3.906 V | 69–71% | 3.272 V | 59–72% |
| 70% | ±10 mV | 3.906 V | 69–71% | 3.272 V | 47–73% |
| 70% | ±20 mV | 3.906 V | 68–72% | 3.272 V | 41–75% |
| 75% | ±1 mV | 3.949 V | 75% | 3.290 V | 75% |
| 75% | ±5 mV | 3.949 V | 74–75% | 3.290 V | 74–76% |
| 75% | ±10 mV | 3.949 V | 74–76% | 3.290 V | 73–77% |
| 75% | ±20 mV | 3.949 V | 73–77% | 3.290 V | 68–82% |
| 80% | ±1 mV | 3.991 V | 80% | 3.307 V | 79–81% |
| 80% | ±5 mV | 3.991 V | 79–80% | 3.307 V | 78–92% |
| 80% | ±10 mV | 3.991 V | 79–81% | 3.307 V | 77–96% |
| 80% | ±20 mV | 3.991 V | 78–82% | 3.307 V | 75–97% |
| 85% | ±1 mV | 4.037 V | 85% | 3.311 V | 83–90% |
| 85% | ±5 mV | 4.037 V | 85–86% | 3.311 V | 79–96% |
| 85% | ±10 mV | 4.037 V | 84–86% | 3.311 V | 78–96% |
| 85% | ±20 mV | 4.037 V | 83–87% | 3.311 V | 75–97% |
| 90% | ±1 mV | 4.084 V | 90% | 3.312 V | 85–94% |
| 90% | ±5 mV | 4.084 V | 90% | 3.312 V | 80–96% |
| 90% | ±10 mV | 4.084 V | 89–91% | 3.312 V | 78–97% |
| 90% | ±20 mV | 4.084 V | 88–92% | 3.312 V | 76–97% |

#### Conditions

- **Cells:** PyBaMM’s Doyle-Fuller-Newman model. LiPo: the Ai2020 parameters, an Enertech LiCoO₂/graphite pouch cell of 2.28 Ah, 3.0 to 4.20 V. LiFe: the Prada2013 parameters, A123’s ANR26650M1 LiFePO₄/graphite cell of 2.3 Ah, 2.0 to 3.60 V.
- **Rest curves:** A C/50 discharge from full to empty, within a few mV of the rest voltage, from the single-particle model with electrolyte. A reading’s range is every sample whose voltage lies within the error.
- **Charges:** 1C until the full voltage, then that voltage until the current falls to C/20. From 10%, at 25 °C.
- **Wrong settings:** LiFe on the LiPo setting: 1C from 90% until 4.20 V. LiPo on the LiFe setting: a full charge to 3.60 V from empty, against one to 4.20 V.
- **Pack:** Four LiFe cells in series, the fourth with 95% of the others’ capacity, all from 20%. 1C until the pack reads 14.40 V, then 14.40 V until C/20.
- **Cold:** The LiPo model, whose parameters change with temperature, held at each temperature throughout. The graphite’s voltage against lithium beside the separator, where it is lowest.
- **Drift:** Arithmetic from TI’s 1 mA offset example on a 2.5 Ah cell
- **Renders:** Blender, both cells at one scale. The LiFe is built to A123’s published size. The LiPo is a generic hobby pouch.

Simulated only. Nothing on this page has been measured on a board yet.

#### Limits

- Past 3.60 V the LiFe model runs beyond its fitted range, and past 4.20 V the LiPo’s. Voltages there are indicative.
- The rest curves are the models’. Real cells differ: TI’s own LiFePO₄ curve spans about 105 mV from 20 to 80%.
- Hysteresis and the hours a LiFe takes to settle are left out of the rest curves.
- The cold runs hold one temperature and ignore the heat a charge makes.
- Datasheet and paper figures are for the cells named beside them, not the modeled ones.

#### Files

- sim/cells.py The two cell models
- sim/scenarios.py Rest curves, charges, wrong settings and the cold
- sim/pack.py The 4S LiFe pack
- render/cells.py The renders
- refs/research.md Every datasheet and paper figure and its source

#### Sources

- [TI, SLYT402, Impedance Track gauging with LiFePO4 cells](https://www.ti.com/lit/pdf/slyt402)
- [TI, SLYT528, LiFePO4 cell balancing with an Impedance Track gauge](https://www.ti.com/lit/pdf/slyt528)
- [Zerkalov, Wortham and Damle, Maxim, fuel gauging LiFePO4 batteries, Electronic Design, 2018](https://www.electronicdesign.com/technologies/power/article/21807294/why-special-care-is-needed-when-fuel-gauging-lifep04-batteries)
- [Barai and others, hysteresis in lithium-ion cells, J. Power Sources, 2015](https://wrap.warwick.ac.uk/70160)
- [Doughty and Roth, Sandia, a general discussion of Li-ion battery safety, ECS Interface, 2012](https://www.electrochem.org/dl/interface/sum/sum12/sum12_p037_044.pdf)
- [Mao and others, overcharge thermal runaway by cathode, J. Energy Storage, 2023](https://doi.org/10.1016/j.est.2023.109421)
- [Golubkov and others, thermal runaway of metal-oxide and olivine cells, RSC Adv., 2014](https://doi.org/10.1039/c3ra45748f)
- [Zinth and others, TUM, neutron study of a cell charged at −20 °C, 2014](https://www.frm2.tum.de/en/frm2/news-single-view-en/article/researchers-observe-the-phenomenon-of-lithium-plating)
- [Keil and others, calendar aging, J. Electrochem. Soc., 2016](https://iopscience.iop.org/article/10.1149/2.0411609jes)
- [Varta, PLF 523450 C datasheet](https://storage.sea.com.ua/tech_info/Varta/DS66280.pdf)
- [EVE, LF280K specification](https://akkudoktor.net/uploads/short-url/maYfKTLNOcRNqlYZNRluaz43RTL.pdf)
- [A123, ANR26650M1-B datasheet](https://bto.pl/files/Karty%20katalogowe/a123%20datasheet_26650m1b.pdf)
- [Victron, Smart LFP batteries datasheet](https://www.victronenergy.com/upload/documents/Datasheet-12,8-&-25,6-Volt-lithium-iron-phosphate-batteries-Smart-EN.pdf)
- [Victron, SmartShunt manual](https://www.victronenergy.com/media/pg/SmartShunt/en/operation.html)
- [Battle Born, heated batteries](https://battlebornbatteries.com/blogs/academy/how-to-wire-integrated-battery-heating-and-heat-enable-the-battle-born-educational-series)
- [Battle Born, charging LiFePO4 batteries](https://battlebornbatteries.com/blogs/articles/charging-battleborn-lifepo4-batteries)
- [SkyRC, B6 Evo manual](https://www.rcscomponents.kiev.ua/datasheets/B6_Evo_Instruction_Manual_EN_V1.0.pdf)
- [Spektrum, SPMB2200LFRX 2S LiFe pack](https://www.spektrumrc.com/product/SPMB2200LFRX.html)
- [Gens Ace 2200 mAh 3S 25C, AMain listing](https://www.amainhobbies.com/gens-ace-3s-lipo-battery-25c-11.1v-2200mah-ga-b1113/p792030)
- [IATA, lithium battery guidance, 2026](https://www.iata.org/contentassets/05e6d8742b0047259bf3a700bc9d42b9/lithium-battery-guidance-document.pdf)
- [PyBaMM, the battery models](https://pybamm.org/)

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---

Source: https://nearfieldnotes.com/notes/lipo-vs-life/

Cite as: Michael Walker, “LiPo vs LiFePO4”, Near Field Notes, Note 18, Rev 1, 6 Nov 2026. https://nearfieldnotes.com/notes/lipo-vs-life/

Figures: free to reuse under CC BY 4.0 (https://nearfieldnotes.com/license/). Each one's image is linked under its name. Credit Michael Walker, Near Field Notes, and link the figure: this address plus #fig- and its number, like https://nearfieldnotes.com/notes/lipo-vs-life/#fig-18.