How-To Guide · Updated November 2026
How to Charge a LiFePO4 Battery: Voltages, Chargers and Cold-Weather Rules
Charging a LiFePO4 battery safely comes down to four settings. Charge at constant current up to 14.2–14.6V for a 12V battery (28.4–29.2V for 24V, 56.8–58.4V for 48V), then stop or hold a low float of about 13.4–13.8V. Turn off equalize, desulfation and temperature compensation. Don't charge below 32°F unless the battery heats itself. Your battery's manual overrides any chart, including ours.
As an Amazon Associate, SolarGenAdvisor earns from qualifying purchases made through links on this page, at no additional cost to you. Voltages come from battery and charger makers' manuals, cited inline. Product scores are AI-synthesized from specs and logged Amazon prices; we did not test these products.
By Quick Answer: LiFePO4 Charging Settings
- Charge (bulk/absorption) voltage, 12V: 14.2–14.6V. Battle Born accepts 14.2–14.6V and recommends 14.4V (Battle Born). LiTime gives 14.4–14.6V (LiTime manual). Victron's Li-ion presets use 14.2V (Victron). RELiON specifies 14.0–14.6V (RELiON).
- 24V and 48V: multiply by 2 or 4. Power Queen lists 28.4–29.2V for 24V and 56.8–58.4V for 48V (Power Queen). Victron's 24V presets are 28.4V absorption and 27.0V float (Victron MPPT manual).
- Float: none, or 13.4–13.8V. The makers disagree (see float vs absorption).
- Turn off: equalize, recondition/desulfation and temperature compensation. RELiON says LiFePO4 needs neither equalizing nor temperature compensation (RELiON).
- Temperature: no charging below 32°F (0°C) unless the battery heats itself. Victron's charger manual says "NEVER" (Victron). LiTime's range is 32–122°F (0–50°C) (LiTime).
- When it's full: once the current tapers in the constant-voltage stage. LiTime calls a charge complete at about 0.02C of residual current, or 2A on a 100Ah battery by our arithmetic (LiTime). Victron's own 12.8V batteries use a 2-hour absorption (Victron).
How to Charge a LiFePO4 Battery, Step by Step
These steps fit any 12V, 24V or 48V LiFePO4 battery with a built-in battery management system (BMS), which covers the drop-in batteries sold for RVs, boats and solar.
- Find your battery's numbers. Look up the charge voltage, float (if any), maximum charge current and charge-temperature range in its manual or on its label. Those beat every generic chart.
- Check the temperature. If the battery is below 32°F and has no heater, warm it first or wait. A battery with a low-temperature cut-off will simply refuse the charge; one without may be damaged.
- Use a LiFePO4 profile. Pick the charger's LiFePO4 or lithium mode, or enter custom values in the 14.2–14.6V range. Don't use a charger made for other lithium-ion chemistries: RELiON warns they are "typically set to a higher voltage than required by LiFePO4" (RELiON).
- Connect in the right order. LiTime's sequence is charger to battery first, then plug into mains; to disconnect, unplug from mains first (LiTime).
- Let it run CC then CV. The charger pushes full amps (constant current) until it reaches the set voltage, then holds that voltage (constant voltage) while the current falls.
- Stop or float low. End the charge when the current tapers, then switch off or drop to a float at or below your battery maker's figure.
- Storing it? Don't top it off. RELiON recommends storing at 50% state of charge (RELiON); LiTime suggests 13.1–13.2V, about 50–60% (LiTime). Our storage and maintenance guide covers the same rules for power stations.
You don't have to charge after every use. RELiON says LiFePO4 batteries "do not get damaged when left in a partial state of charge" and can be recharged after each use or once they reach 20% (RELiON).
LiFePO4 Battery Voltage Chart (12V, 24V, 48V)
A 12V LiFePO4 battery is 4 cells in series, a 24V battery 8 and a 48V battery 16, so each column is the cell voltage times 4, 8 or 16. Read the battery at rest: LiTime's state-of-charge figures are open-circuit voltages after at least 3 hours with nothing connected (LiTime manual). A battery on a charger reads higher, and one under load reads lower.
| State of charge | 1 cell (3.2V) | 12V (12.8V) | 24V (25.6V) | 48V (51.2V) |
|---|---|---|---|---|
| 100% (while charging) | 3.65V | 14.6V | 29.2V | 58.4V |
| 100% (at rest) | 3.40V | 13.6V | 27.2V | 54.4V |
| 90% | 3.35V | 13.4V | 26.8V | 53.6V |
| 80% | 3.32V | 13.3V | 26.6V | 53.1V |
| 70% | 3.30V | 13.2V | 26.4V | 52.8V |
| 60% | 3.27V | 13.1V | 26.1V | 52.3V |
| 50% | 3.26V | 13.0V | 26.1V | 52.2V |
| 40% | 3.25V | 13.0V | 26.0V | 52.0V |
| 30% | 3.22V | 12.9V | 25.8V | 51.5V |
| 20% | 3.20V | 12.8V | 25.6V | 51.2V |
| 10% | 3.00V | 12.0V | 24.0V | 48.0V |
| 0% | 2.50V | 10.0V | 20.0V | 40.0V |
Source: Renogy LiFePO4 voltage chart. The "while charging" row is the charge voltage, not a resting reading.
Where the makers' charts disagree (12V, at rest)
Battery makers publish different resting voltages for the same state of charge. Across these four charts, "50%" runs from 13.0 to 13.2V:
| State of charge | Renogy | Power Queen | LiTime manual (3 h rest) | LiTime chart |
|---|---|---|---|---|
| 100% | 13.6 | 13.33 or more | about 13.33 | — (14.6 while charging) |
| about 75% | 13.2–13.3 (70–80%) | 13.3–13.33 | 13.2–13.3 | — |
| 50% | 13.0 | 13.15–13.2 | 13.1–13.2 | 13.2 |
| about 25% | 12.8–12.9 (20–30%) | 13.0–13.15 | 13.0–13.1 | 13.0 (20%) |
| 0% | 10.0 | 10–12 | 10–12 | 10.0 (cut-off) |
Volts. Sources: Renogy; Power Queen (its 24V and 48V columns are the 12V figures ×2 and ×4); LiTime user manual; LiTime voltage chart, which labels only its 90% row as resting.
Why a voltmeter is a rough gauge. From 90% down to 20%, Renogy's chart drops only 0.6V (13.4 to 12.8V), and its 40% and 50% rows are both 13.0V, so a 0.1V meter error or a battery that hasn't fully rested can shift the estimate by 10 to 20 points. RELiON says a voltage-based fuel gauge designed for lead-acid "will not accurately display" a LiFePO4 battery's state of charge, and recommends one that measures current instead (RELiON). A battery with Bluetooth, or a shunt-type battery monitor, does that. Voltage is most useful at the ends: about 13.3–13.6V at rest means full, and below about 12V it's nearly empty.
Charge Settings by Source: AC Charger, Solar, Alternator, Generator, RV Converter, Power Station
Whatever the energy source, the battery only sees the device that regulates the voltage. Set that device up correctly and the source doesn't matter. Here's what to check for each one (12V figures; double for 24V, quadruple for 48V):
| Source | What sets the voltage | Settings to use | Watch out for |
|---|---|---|---|
| AC charger | The charger | LiFePO4 mode, 14.2–14.6V, no float or a low one | Lead-acid "repair" or recondition modes |
| Solar (MPPT) | The charge controller | LiFePO4 preset or custom: 14.2–14.6V, float 13.4–13.6V or off, equalize off | Lead-acid default left on; temperature compensation |
| Alternator | A DC-DC charger (recommended) | LiFePO4 profile, current limit sized to the alternator | Alternator overheating on a direct connection |
| Generator | The charger or converter you plug in | Same as AC charger | The generator's unregulated 12V DC outlet |
| RV converter | The converter/charger | Lithium model or mode, e.g. 14.4V charge / 13.6V idle | Old lead-acid converters that never reach full |
| Power station | Its built-in charger and BMS | Nothing to set; follow its charge-temperature range | Charging it in a freezing car or garage |
AC battery charger
A dedicated LiFePO4 charger is the simplest option: it charges at constant current to 14.6V, then holds it. Power Queen's 20A model charges to 14.6V with no float stage and can wake a battery whose BMS has shut off (Amazon listing). A multi-mode charger works too if you select its lithium mode. Victron's Blue Smart IP65 Li-ion mode is 14.2V absorption, 13.5V float and 13.5V storage, and its lead-acid modes are not for lithium (Victron manual). Size the amps to the battery: LiTime's general manual suggests 10A from an AC charger, or up to 25A for fast charging (LiTime). Always stay within your battery's rated maximum charge current.
| Battery (fully discharged) | 5A charger | 10A charger | 20A charger |
|---|---|---|---|
| 12V 50Ah | ~11 h | ~5.5 h | ~3.0 h |
| 12V 100Ah | ~21 h | ~11 h | ~5.5 h |
| 12V 200Ah | ~41 h | ~21 h | ~11 h |
| 12V 300Ah | ~61 h | ~31 h | ~16 h |
Our estimate, not a measurement: amp-hours ÷ charger amps + about 0.5 hour. Victron says a lithium battery is over 95% charged when absorption starts and full after about 30 minutes of it (Victron). Loads running during the charge, thin cables or a heater warming the cells add time.
Solar charge controller (MPPT settings)
Most MPPT controllers ship set for lead-acid, so check the setting before the first sunny day. Victron's SmartSolar 100/30 and 100/50 have a LiFePO4 position (switch position 7) at 14.2V absorption and 13.5V float, with equalization not available for lithium (Victron MPPT manual). LiTime's settings for its batteries are a little higher (LiTime manual). If your controller has no LiFePO4 preset, enter custom values:
| Controller setting | 12V | 24V | 48V | Source |
|---|---|---|---|---|
| Absorption (boost) | 14.2–14.6V | 28.4–29.2V | 56.8–58.4V | Victron 14.2V; LiTime 14.4–14.6V |
| Absorption time | Battery maker's figure; end on a current tail of about 0.02C if the controller allows it | LiTime; Victron's default is adaptive, up to 6 h | ||
| Float | 13.4–13.6V or off | 26.8–27.2V | 53.6–54.4V | Victron 13.5V; LiTime 13.4–13.6V |
| Equalize | Off | Victron (n/a for lithium); RELiON | ||
| Temperature compensation | Off (0 mV/°C) | LiTime "off or minimal"; RELiON | ||
| Over-voltage disconnect / reconnect | 15.0V / 14.2V | 30.0V / 28.4V | 60.0V / 56.8V | LiTime (12V); others ×2, ×4 |
| Low-voltage disconnect / reconnect (load output) | 11.6V / 12.4V | 23.2V / 24.8V | 46.4V / 49.6V | LiTime (12V); others ×2, ×4 |
| Low-temperature charge cut-off | 5°C (41°F) if the controller has a battery temperature sensor; otherwise rely on the battery's BMS | Victron (needs a networked temperature sensor) | ||
Sources: Victron SmartSolar MPPT 100/30 & 100/50 manual; LiTime user manual; RELiON. The 24V and 48V columns are our multiplication of the 12V figures; Victron's own 24V preset is 28.4V absorption and 27.0V float.
Size the controller to the panels: Victron rates the 100/30 for 440W of panels on a 12V battery (880W on 24V). LiTime suggests at least 150W of panels for its 12V batteries (LiTime). Both MPPT controllers we've rated showed a future availability date on Amazon when we checked on November 8, so we're not linking them here; complete panel-plus-controller setups are in our best RV solar kit guide.
Alternator and DC-DC charger
A LiFePO4 bank will take as much current as an alternator can give for a long time. Battle Born says "if the alternator tries to meet that demand for too long, it can overheat," that most alternators can handle about half their rated amps continuously, and that "a DC-DC charger is the best alternator charging solution for most vehicles" because it limits how much current the house bank can pull (Battle Born). RELiON adds that a poorly regulated alternator can make the BMS disconnect the battery, which "may" damage the alternator (RELiON).
- Pick the LiFePO4 profile on the DC-DC charger and an output current your alternator can sustain. LiTime puts typical DC-DC current at 20–40A (LiTime).
- Protect the starter battery. LiTime describes DC-DC charging that starts at 13.3V or more and stops at 12.6V or less on the starter side (LiTime). Renogy's 40A model detects when the engine is running before it charges.
- Smart (variable-voltage) alternators need a DC-DC charger that supports them. Check your vehicle's documentation, and pick a charger whose listing says it works with smart alternators.
Alternator-only DC-DC charger
Renogy 40A DC-DC Battery Charger · 40A · Score 62/100
Alternator-only 40A DC-DC charger with engine-running detection, smart-alternator support, a LiFePO4 profile with lithium activation and up to 94% efficiency per Renogy; app monitoring needs the separately sold BT-2 module and there is no solar input.
Price: $179.99
Generator
Plug a LiFePO4 charger, your RV's converter or an inverter-charger into the generator's AC outlet, and those settings apply. Don't use the generator's 12V DC outlet: Honda's EU2000i inverter generator manual says it "should ONLY be used for charging 12-volt automotive type batteries" and that "the DC charging output is not regulated" (Honda EU2000i manual). The charger, not the generator, limits the charge rate. A 20A charger delivers about 290W of DC (20A × 14.6V, our arithmetic), well within even a small inverter generator. For RV generator sizing, see our best generator for RV picks.
RV converter/charger
The converter charges the house battery whenever you're on shore power or a generator. Lithium-rated converters use a LiFePO4 profile. Progressive Dynamics' two-stage lithium models charge at 14.4V for at least 1 hour and up to 8 hours, drop to a 13.6V idle, and top the battery off every 3 weeks on long hookups (Progressive Dynamics). An older lead-acid converter that holds around 13.6V usually won't hurt a LiFePO4 battery, but it may never fill it. RELiON says charging below its range leaves the battery at a partial state of charge without harming it (RELiON). The real problem is a converter with an automatic equalize or desulfation step (see below). Choosing the battery itself? Our best LiFePO4 battery for RV guide covers converter swaps and tray sizes.
Portable power station
A LiFePO4 power station has its charger and BMS built in, so there's nothing to set: plug it into the wall, a car socket or solar and it manages the charge itself. What you can control is temperature. Anker, for example, lists a 32–104°F charging range for its SOLIX C1000 but a -4–104°F discharging range (Anker). So a station can run lights in a cold garage and still refuse to charge there. Check your model's manual for its range. A power station can also charge a separate 12V LiFePO4 battery: plug a LiFePO4 AC charger into the station's AC outlet. Our LiFePO4 solar generator guide explains why most stations now use this chemistry.
Charging LiFePO4 in Cold Weather: The 32°F Rule
Don't charge a standard LiFePO4 battery below 32°F (0°C). Discharging in the cold is fine within the battery's range; charging is the risk. The makers set the line in slightly different places:
| Source | Cold-charging rule |
|---|---|
| Victron (charger manual) | "NEVER attempt to charge a Li-ion battery when its temperature is below 0°C (32°F)" (Victron) |
| Victron (its own Lithium Smart batteries) | Charging allowed from 5°C (41°F) by default; Victron says its cells "will sustain permanent damage when charged at temperatures below 5°C" (Victron) |
| LiTime | Ideal charging 0–50°C (32–122°F); below 0°C only with a low-temperature limit or pre-heating (LiTime) |
| Battle Born | Keep the battery above 35°F; heated versions keep the cells above freezing (Battle Born) |
| RELiON (its own batteries) | Full rate from 32 to 131°F; 0.1C from 32 down to 14°F; 0.05C from 14 down to -4°F (RELiON) |
RELiON's reduced-current rule is for RELiON batteries and their data sheets only. Don't apply it to another brand unless that maker says so.
The charger usually doesn't know the battery's temperature. Victron's MPPT controllers can stop charging at 5°C only with a networked battery temperature sensor (Victron). So the protection normally comes from the battery itself, in one of three forms:
- Low-temperature charge cut-off: the BMS blocks charging until the cells warm. Your solar or alternator charging simply stops on a cold morning, which is normal, not a fault.
- Self-heating: the battery uses incoming charge power to warm its cells first, then charges. Heating draws from the charger, so a bigger charger gets there sooner.
- Nothing listed: keep the battery somewhere heated while it charges, or bring it inside.
Three 12V 100Ah batteries we've already rated, and how each handles cold charging:
| Battery (our score) | Cold charging | Flat to full on a 20A charger | Price |
|---|---|---|---|
| LiTime 12V 100Ah Group 24 Self-Heating Bluetooth LiFePO4 (81/100) | Self-heating: warms the cells when a charger is connected below 41°F, charges from 50°F (maker page) | ~5.5 h (plus heating time when cold) | $368.99 |
| Power Queen 12V 100Ah Group 24 Dual-Mode Self-Heating Bluetooth LiFePO4 (81/100) | Self-heating: automatic below 41°F while charging, or preheat from the app (maker page) | ~5.5 h (plus heating time when cold) | $287.99 |
| Power Queen 12V 100Ah Group 24 Smart Bluetooth LiFePO4 (82/100) | No heater: charging stops below 32°F and resumes at 41°F (maker page) | ~5.5 h (plus heating time when cold) | $289.99 |
Each stores 1,280 Wh, about 1,088 Wh usable through an inverter (Wh × 0.85), enough to run a 60W load for roughly 18 hours. If your battery lives in a heated space or you winter somewhere warm, the cheaper non-heated Power Queen is enough. For a bay that freezes, pay for the heater. Compare them all in our best 12V lithium battery guide.
NMC lithium-ion batteries have the same no-charge-below-freezing limit. Our LiFePO4 vs NMC comparison covers how the two chemistries differ in cold and in cycle life.
Float vs Absorption: Does a LiFePO4 Battery Need a Float Charge?
Lead-acid batteries need a float because they self-discharge. LiFePO4 doesn't need one, and holding a lithium battery at a high voltage for weeks isn't helpful. The makers agree on that much. They disagree on whether a low float is acceptable, and how low:
| Source | Absorption (12V) | Float (12V) |
|---|---|---|
| Battle Born | 14.2–14.6V; 14.4V recommended | "Not necessary"; under 13.6V is fine |
| LiTime | 14.4–14.6V | "No permanent float"; 13.4–13.6V if needed |
| Victron (Lithium Smart battery) | 14.2V for 2 hours | 13.5V |
| RELiON | 14.0–14.6V | 13.8V |
| Progressive Dynamics lithium converter | 14.4V, 1–8 hours | 13.6V idle |
Sources: Battle Born; LiTime; Victron; RELiON; Progressive Dynamics.
What to do in practice:
- Battery used daily (solar, van): a float of about 13.4–13.5V lets solar run the loads during the day without cycling the battery, which is why Victron's presets include one.
- Charger left on for weeks: use no float, or the lowest float your battery maker allows. A charger with a separate storage voltage, like Victron's 13.5V, also works.
- Absorption length: long enough for the current to taper. At the very top of charge the BMS balances the cells (next sections), so a too-short absorption every time can leave them slightly uneven.
- If the numbers conflict, use your battery maker's. RELiON's 13.8V float is above Battle Born's and LiTime's ceilings, and that's fine for RELiON batteries.
BMS Cutoffs: What the Battery Does When a Setting Is Wrong
Every drop-in LiFePO4 battery has a battery management system that disconnects the cells when something goes outside its limits. It's the last line of defense, not a substitute for correct charger settings:
- Over-voltage. RELiON says if a charger goes over 14.6V, "the BMS will sense the over-voltage and disconnect" (RELiON). LiTime gives 15.0V as the over-voltage protection point and says charging resumes once the voltage falls below 14.2V (LiTime). A charger that keeps hitting this point isn't set up correctly.
- Under-voltage. LiTime lists 10.8V for inverter use (LiTime). Victron's Lithium Smart battery cuts loads when any cell reaches 2.8V by default (Victron). RELiON says that if the BMS disconnects for low voltage (the battery will read under 8V), remove the load and charge immediately (RELiON).
- Temperature. High or low temperature shuts off charging (and, at the extremes, discharging) until the cells recover.
- A "dead" battery that reads 0V. After an under-voltage cut-off, many chargers can't see the battery. A charger with 0V activation can wake it. Our charger guide walks through waking a LiFePO4 battery whose BMS shut off.
Balancing: Cells Inside the Battery, and Batteries in Series or Parallel
Cell balancing happens near full charge. The BMS evens out small differences between the four cells of a 12V battery at the top of the charge. Victron says its BMS may switch the charger off and on repeatedly until the cells balance, and that the battery is fully charged when it reaches float and the app shows the cells as "balanced" (Victron). If a battery is never charged to full, it never gets that chance.
Battery balancing is your job. When you wire two or more batteries together:
- Start matched. Use identical batteries with the same capacity and state of charge. LiTime says to fully charge each battery, then connect them in parallel for 12–24 hours to equalize before putting them in service, and allows up to 4 in series and 4 in parallel (LiTime). RELiON wants each battery within 0.05V (50 mV) of the others before installation (RELiON).
- Series banks (24V or 48V from 12V batteries): RELiON says it's best to charge with a multi-bank charger that charges each battery individually, and to recharge each one separately if any drifts more than 0.05V from the rest (RELiON).
- Parallel banks: LiTime recommends re-balancing every 6 months (LiTime).
- Never mix chemistries. LiTime says not to connect LiFePO4 in parallel with lead-acid or gel batteries (LiTime).
Why a Lead-Acid Charger or Desulfation Mode Is a Problem
A lead-acid charger isn't automatically wrong. RELiON says most can be used if they are within LiFePO4 voltage guidelines, that AGM and gel algorithms "typically fall within" them, and that because the BMS protects the battery, a lead-acid charger "will usually not damage the battery" (RELiON). The trouble comes from four lead-acid features:
- Desulfation, repair and recondition modes. These deliberately push the voltage far above lithium limits. NOCO's 12V Repair mode drives up to 16.5V and is "for 12-volt lead-acid batteries only" (NOCO GENIUS10 guide). Victron's lead-acid recondition steps run at 16.2V and 16.5V (Victron). That's well past the 15.0V over-voltage point LiTime gives, so the BMS has to cut off.
- Flooded-battery profiles. RELiON says flooded algorithms often run higher than LiFePO4 needs, so the BMS disconnects at the end of the charge and the charger may show an error code. Its fix is a charger with a LiFePO4 profile (RELiON).
- Temperature compensation. Lead-acid chargers raise the voltage in the cold. Victron applies 16 mV per °C in its lead-acid modes; by our arithmetic that adds about 0.4V at 32°F, taking a 14.4V setting near 14.8V. LiTime wants compensation "off or minimal" for LiFePO4 (LiTime).
- A long, high float. Victron's lead-acid float is 13.8V (Victron), above Battle Born's and LiTime's 13.6V ceiling, though within RELiON's figure.
If your charger lets you see and set its absorption (14.2–14.6V) and float (13.6V or lower) and has no automatic equalize or desulfation step, it can work. If not, a charger with a dedicated LiFePO4 mode is the safer choice. Our LiFePO4 charger guide goes through lead-acid charger compatibility in more detail.
Do You Need New Charging Gear?
Buy a LiFePO4 charger or DC-DC charger if
- ✓ Your charger has no lithium mode, or runs an automatic equalize or desulfation step
- ✓ You charge from a vehicle alternator with no current limit
- ✓ Your converter is lead-acid only and the battery never reaches full
- ✓ Your battery has tripped its BMS and your charger won't start on it
Keep what you have if
- ✗ It already offers 14.2–14.6V absorption and a float of 13.6V or less (or your maker's figure)
- ✗ Your solar controller has a LiFePO4 preset you can select
- ✗ You use a power station: its charger is built in
- ✗ Your only problem is cold: that needs a heated battery or a warmer location, not a new charger
Charging a LiFePO4 Battery: FAQ
What voltage should I charge a 12V LiFePO4 battery to?
Usually 14.2 to 14.6 volts in the absorption stage. Battle Born recommends 14.4V and accepts 14.2 to 14.6V, LiTime gives 14.4 to 14.6V, Victron's lithium presets use 14.2V and RELiON specifies 14.0 to 14.6V. For a 24V battery double it (28.4 to 29.2V), and for a 48V battery multiply by four (56.8 to 58.4V). Your battery maker's figure comes first.
What is a LiFePO4 battery's voltage at 50 percent?
About 13.0 to 13.2 volts at rest for a 12V battery, depending on whose chart you use: Renogy lists 13.0V, LiTime's manual 13.1 to 13.2V and Power Queen 13.15 to 13.2V. That is 26.0 to 26.4V for 24V and 52.0 to 52.8V for 48V. Measure after the battery has rested for a few hours with nothing connected; LiTime uses at least 3 hours. Because the curve is so flat, a battery monitor that counts current is more accurate than a voltmeter.
Can I charge a LiFePO4 battery with a regular lead-acid charger?
Sometimes. RELiON says most lead-acid chargers work if their voltages fall within LiFePO4 guidelines, and that AGM and gel settings usually do. Avoid any charger with an automatic equalize, desulfation, repair or recondition step, which can push 16V or more, and flooded-battery profiles that run high. Temperature compensation should be off. A charger with a dedicated LiFePO4 mode avoids the guesswork.
Do LiFePO4 batteries need a float charge?
No. Battle Born says float charging is not necessary, though a float under 13.6V is fine, and LiTime advises no permanent float, or 13.4 to 13.6V if one is needed. Victron uses a 13.5V float on its lithium presets, and RELiON specifies 13.8V for its batteries. A low float is useful when solar or shore power runs loads all day; a charger left on for weeks should use no float or the lowest your maker allows.
Can you charge a LiFePO4 battery below freezing?
Not a standard one. Victron says never to charge a lithium battery below 32 degrees F, and LiTime allows charging below 0 degrees C only with a low-temperature limit or pre-heating. Self-heating batteries warm their cells with charger power first, then charge. RELiON is an exception for its own batteries, allowing reduced current (0.1C down to 14 degrees F), so check your battery's data sheet before relying on that.
What are the best MPPT settings for a 12V LiFePO4 battery?
Absorption 14.2 to 14.6V, float 13.4 to 13.6V or off, equalize off and temperature compensation off. LiTime adds an over-voltage disconnect of about 15.0V (reconnect 14.2V) and a low-voltage disconnect of about 11.6V (reconnect 12.4V). Victron's SmartSolar LiFePO4 preset is 14.2V absorption and 13.5V float. Double every figure for 24V and multiply by four for 48V.
How long does it take to charge a 100Ah LiFePO4 battery?
Roughly the amp-hours divided by the charger's amps, plus about half an hour. A flat 100Ah battery takes about 5.5 hours on a 20A charger, about 10.5 hours on 10A and about 20.5 hours on 5A. Victron says a lithium battery is over 95 percent charged when the absorption stage starts and full after about 30 minutes of it. Cold batteries that heat themselves first take longer.