Can you charge a lithium battery below freezing?

No. A lithium battery should not be charged when its cells are below 0 degrees C (32 degrees F), and that holds for every consumer cell datasheet and device specification we checked that gives a charging range. Warm it first. The line most people miss sits higher: below 10 degrees C, Panasonic tells designers to charge its NCR18650B cell at about half its standard rate. Using a cold battery is fine. Charging it is the problem.

Why is 0 degrees C the limit everyone quotes?#

Charging pushes lithium ions into the graphite of the negative electrode. When they cannot get in fast enough, they deposit on the surface as metallic lithium. Researchers at the Karlsruhe Institute of Technology describe this lithium plating as taking place "at conditions of high currents and/or low temperatures", with the main cause being "the slow solid-state diffusion of lithium inside the active material". Plating "can cause an irreversible capacity fade", and "dendritically grown lithium can lead to an internal short circuit".

Cold slows that diffusion, so a current that charges a warm cell safely can plate a cold one. Two consequences follow.

First, plating depends on current and temperature together. The Karlsruhe group tested graphite between 0 and 25 degrees C and found "plating is more pronounced at lower temperatures". There is no sudden switch at 0 degrees C; it is a sliding scale that cell makers cut off at a round number.

Second, it is the cell's temperature that counts, not the air's. A bank brought from a minus 10 degree C vestibule into a warm tent warms on the outside long before the cells in the middle catch up.

Below 0 degrees C the consumer cell datasheets give no charging rating at all. Further down the chemistry barely works: a 2025 laboratory study of graphite electrodes by Chen and colleagues at the City College of New York found that intercalation, the reaction a charge depends on, "drops precipitously as temperature decreases below minus 20 degrees C".

Charging and using temperatures, side by side#

Here are the limits printed for cells and for the devices built around them.

Every device that states a charging range starts it at 0 degrees C, even where it runs far colder: the Garmin works to minus 20 but charges only from 0. And the discharge column is always wider than the charge column.

The 0 to 10 degree band nobody mentions#

Most advice stops at "not below freezing", as if 1 degree C were as good as 20. Panasonic's NCR18650B datasheet carries a footnote on the charge range: "At temperatures below 10 degrees C, charge at a 0.25C rate." The standard charge for that cell is 1,625 mA, close to 0.5C, so below 10 degrees C the permitted current roughly halves.

Translated into something you carry, a hypothetical 10,000 mAh power bank built from three of these cells in parallel works like this:

• Capacity: 3 x 3,350 mAh = 10,050 mAh at 3.6 V nominal.
• Standard charge: 3 x 1,625 mA = 4.9 A into the cells, about 17.6 W.
• Below 10 degrees C: 0.25C is 0.84 A per cell, 2.5 A in total, about 9.0 W.

Nitecore's SUMMIT 20000, for scale, accepts 18 W (9 V at 2 A). If our bank took 18 W and put about 16 W into its cells (we assume 90 percent converter efficiency), that is 4.4 A, or 0.44C: 1.75 times what this datasheet allows below 10 degrees C. Whether a given bank throttles itself in that band is not something you can see from the outside.

The lithium iron phosphate specification from KAMCY shows the same idea in finer steps. It allows charging well below freezing, but only at currents that fall steeply with temperature. The table below takes the highest charging step in each band:

Between 25 degrees C and the band just below freezing the allowed current falls to about a seventh. At minus 20 it is a fortieth. The same document warns that with imprecise charging current, low-temperature charging can cause lithium plating and "rapid decline in battery capacity". Charging below 0 degrees C is possible for a cell engineered and controlled for it, not something to improvise with a phone and a cable.

Why two answers circulate#

One answer says never below freezing. The other says lithium iron phosphate is fine in the cold, or that a battery's own electronics cut off at 25 degrees F, so a little below freezing must be acceptable.

Battle Born's article contains both. It says its battery management system will not accept charge "when the internal temperature of the battery drops below 25 degrees F", about minus 4 degrees C. A few paragraphs later it says: "You should never charge any battery when its internal temperature dips below freezing." The 25 degree F cutoff is the last line of defence, not the operating advice.

Lithium iron phosphate is not exempt: KAMCY's LFP specification warns of plating during cold charging, and Jackery's LiFePO4 station specifies 0 to 45 degrees C. A heated battery or a specification like KAMCY's moves the floor by controlling temperature and current, not by changing the chemistry.

The working rule: 0 degrees C is the floor for anything you own unless its manual says otherwise and explains how.

Using a cold battery is safe, just weaker#

Discharging has a much wider window, down to minus 20 degrees C for the Panasonic and LG cells and minus 40 for the Molicel. What you lose is capacity, and it comes back on warming. LG's MJ1 specification gives a clean figure: a cell charged at room temperature and discharged at 0.2C delivers 80 percent of its initial capacity at 0 degrees C and 70 percent at minus 10. That matches the roughly 20 percent near-freezing shortfall used in our power bank sizing guide and in the power budget calculator.

Apple says the same of iPhones: below 0 degrees C ambient a phone "might temporarily shorten battery life and could cause your device to turn off". That is not damage.

So a cold bank charging a warm phone is acceptable: the bank is discharging and the warm phone takes the charge. A warm bank charging a phone that spent the day in an outside pocket is the risky combination, because the phone's cell is the one being charged cold. An iPhone may refuse with "Charging On Hold"; do not count on every device doing that.

Self-heating banks and power stations#

Batteries marketed for the cold do not change the chemistry; they add a heater. The Nitecore SUMMIT 20000 is rated for use from minus 40 to 40 degrees C ambient. Below 0 degrees C it enters a Low Temperature Heating Mode automatically when anything is plugged in, and below minus 10 degrees C ambient it "needs to be heated for 5 to 10 minutes before it can be used".

Power stations follow the same pattern. The Jackery Explorer 1000 v2 charges from 0 to 45 degrees C and discharges from minus 10. A unit that spent the night in a minus 10 degree vehicle weighs kilograms and warms far more slowly than the cabin air; if it refuses to charge on a cold morning, it is protecting itself. The full vehicle setup is in 12 volt power and camping fridges.

A decision rule for a cold trip#

Work from the battery's temperature, not the forecast.

1. Below 0 degrees C: do not charge, unless the device has a heater and its manual says it charges in the cold. Using it is fine.
2. 0 to 10 degrees C: charge slowly if you must (a small 5 V charger, a low-current mode, a weak panel), or warm it further.
3. 10 to 35 degrees C: charge normally. Every specification on this page agrees here.
4. Above 35 to 45 degrees C: stop, and keep a charging bank out of direct sun.

In practice the bank and phone spend the night inside your sleeping bag or quilt, close to body temperature, and charge there or in the morning (quilts against sleeping bags covers how much room there is). Do not bury a bank under insulation while it is charging: it needs to shed heat.

Solar is where this goes wrong most often. A panel and bank left out overnight start charging at first sun, when the bank is coldest. Bring the bank in, warm it, and connect it mid-morning; early harvest is small anyway, as solar for camping shows.

Test it yourself: how long does your bank take to warm?#

Warm-up time depends on the bank's mass and case, so measure it. You need a kitchen probe thermometer, tape, a freezer and a sealable plastic bag.

1. Charge the bank to about half, seal it in the bag against condensation, and freeze it at about minus 18 degrees C for three hours, within the minus 20 degree storage limit of the Panasonic and LG datasheets.
2. Tape the probe flat against the middle of the bank's largest face, still in the bag.
3. Put it in an inside jacket pocket you are wearing and note the time.
4. Record the minutes to reach 10 degrees C on the case, then 20.
5. Add a margin: the case warms before the cells in the middle.

Write the time on a piece of tape on the bank. That is your minimum wait before charging on a cold trip.

Common mistakes#

Charging the moment you reach the hut or car. The air is warm, the battery is not. Phones and headlamps warm faster than a thick power bank, so charge them first.

Assuming 2 degrees C is fine because it is above freezing. It is inside the rated window, but at least one cell maker halves the permitted current below 10 degrees C. Charge slowly or wait.

Trusting the battery to protect itself. Some do: Apple pauses charging, Battle Born's BMS refuses below 25 degrees F, Nitecore heats. But a manual with no stated charging temperature is not giving permission.

Leaving a headlamp charging in the vestibule. A lamp with a built-in pack is a lithium cell like any other. Our headlamp guide covers why a spare lamp on lithium primary cells is the better cold-weather backup.

Charging straight out of a freezing car or shed. Cold storage within the datasheet range is fine; charging before warming is not. See storing gear between trips.

Frequently asked questions#

Can I charge my phone in the cold?#

Not if the phone itself is below 0 degrees C. Apple designs iPhones for use between 0 and 35 degrees C ambient and says a cold device "might not charge or could stop charging". Warm the phone in an inside pocket or sleeping bag first. The power bank can be cold, because it is discharging, which common lithium cells tolerate down to minus 20 degrees C.

Can you charge a power bank below freezing?#

No, unless its manual says it can and explains how. The lithium-ion cell datasheets checked here all set the charging floor at 0 degrees C, and below 10 degrees C at least one maker halves the permitted current. Cold-rated banks such as the Nitecore SUMMIT 20000 carry a heater. Without one, warm the bank first.

Can LiFePO4 batteries be charged below freezing?#

Not without a heater or a published low-temperature profile. Jackery's LiFePO4 power station charges from 0 to 45 degrees C. Some cell specifications allow charging colder, but only at sharply reduced currents under a battery management system, and heated LiFePO4 batteries warm themselves first. Otherwise, treat 0 degrees C as the limit.

What happens if you charge a lithium battery below 0 degrees C?#

Metallic lithium can deposit on the graphite anode instead of entering it. Plating "can cause an irreversible capacity fade", according to researchers at the Karlsruhe Institute of Technology, and lithium that grows in dendrites can cause an internal short circuit. Unlike cold-weather sluggishness, that lost capacity does not return when the battery warms.

Is it safe to use a power bank in freezing weather?#

Yes. Discharging is rated far below freezing: minus 20 degrees C for common Panasonic and LG cells, minus 40 for some high-power cells. You lose capacity, 20 percent at 0 degrees C and 30 percent at minus 10 for the LG MJ1, and it returns when the bank warms. An inside pocket keeps more of it available.

Why will my power bank not charge in the cold?#

Often because its protection circuit has measured a cell temperature below its charging limit and is refusing current, which is what it should do. On an iPhone the same thing shows as Charging On Hold. Bring the bank somewhere warm, give it time, and try again. If it still refuses at room temperature, the cause is something other than cold.