BU-410: Charging at High and Low Temperatures

Learn how to extend battery life by moderating ambient temperatures.

Rechargeable batteries operate at a wide temperature range but this does not give license to charge them at extreme temperatures. Extreme cold and high heat reduce charge acceptance, and the battery must be brought into moderate temperature conditions before charging.

Older battery technologies, such as Lead acid and NiCd, have higher charging tolerances than newer systems and can be charged below freezing at a C-rate of 0.1C. This is not possible with most NiMH and lithium-ion systems. Table 1 summarizes the permissible charge and discharge temperatures of common lead acid, NiCd, NiMH and Li ion. The table excludes specialty batteries that are designed to charge outside these parameters.


Battery Type

Charge Temperature

Discharge Temperature

Charge Advisory

Lead acid

–20°C to 50°C
(–4°F to 122°F)

–20°C to 50°C
(–4°F to 122°F)

Charge at 0.3C or lessbelow freezing.
Lower V-threshold by 3mV/°C when hot.

NiCd, NiMH

0°C to 45°C
(32°F to 113°F)


–20°C to 65°C
(–4°F to 149°F)


Charge at 0.1C between –18°C and 0°C.

Charge at 0.3C between 0°C and 5°C.
Charge acceptance at 45°C is 70%. Charge acceptance at 60°C is 45%.


0°C to 45°C
(32°F to 113°F)

–20°C to 60°C
(–4°F to 140°F)

No charge permitted below freezing.
Good charge/discharge performance at higher temperature but shorter life.

Table 1: Permissible temperature limits for various batteries. Batteries can be discharged over a large temperature range but charge temperature is limited. For best results, charge between 10°C and 30°C (50°F and 86°F). Lower the charge current when cold.

Low-temperature Charge

Fast charging of most batteries is limited to a temperature of 5 to 45°C (41 to 113°F); for best results consider narrowing the temperature bandwidth to between 10°C and 30°C (50°F and 86°F). Nickel-based batteries are most forgiving in accepting charge at low temperatures, however, when charging below 5°C (41°F), the ability to recombine oxygen and hydrogen diminishes. If NiCd and NiMH are charged too rapidly, pressure builds up in the cell that will lead to venting. Not only do escaping gases deplete the electrolyte, the hydrogen released is highly flammable. The charge current of all nickel-based batteries should be reduced to 0.1C below freezing.

Nickel-based chargers with NDV full-charge detection offer some protection when fast-charging at low temperatures; the poor charge acceptance when cold mimics a fully charged battery. This is in part caused by a high pressure buildup due to the reduced ability to recombine gases at low temperature. Pressure rise and a voltage drop at full charge appear to be synonymous.

To enable fast-charging at all temperatures, some industrial batteries include a thermal blanket that heats the battery to an acceptable temperature; other chargers adjust the charge rate to prevailing temperatures. Consumer chargers do not have these provisions and the end user should only charge at room temperatures.

Lead acid is reasonably forgiving when it comes to temperature extremes, as the starter batteries in our cars reveal. Part of this tolerance is credited to their sluggish behavior. The recommended charge rate at low temperature is 0.3C, which is almost identical to normal conditions. At a comfortable temperature of 20
°C (68°F), gassing starts at charge voltage of 2.415V/cell. By lowering the temperature to 20°C (0°F), the gassing threshold rises to 2.97V/cell.

Do not freeze a lead acid battery. This would cause permanent damage. Always keep the batteries fully charged. In the discharged state the electrolyte becomes more water-like and freezes earlier than when fully charged. According to BCI, a specific gravity of 1.15 has a freezing temperature of 15°C (5°F). This compares to 55°C (67°F) for a specific gravity of 1.265; a fully charged starter battery. Flooded lead acid batteries tend to crack the case and cause leakage if frozen; sealed lead acid packs lose potency and only deliver a few cycles before a replacement is necessary.

Li ion batteries offer reasonably good charging performance at cooler temperatures and allow fast-charging in a temperature bandwidth of 5 to 45°C (41 to 113°F). Below 5°C, the charge current should be reduced, and no charging is permitted at freezing temperatures. During charge, the internal cell resistance causes a slight temperature rise that compensates for some of the cold. With all batteries, cold temperature raises the internal resistance.

Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a subfreezing charge. The plating is permanent and cannot be removed with cycling. Batteries with lithium plating are more vulnerable to failure if exposed to vibration or other stressful conditions. Advanced chargers (Cadex) prevent charging Li-ion below freezing.

Manufactures seek ways to charge Li-ion below freezing. Charging is indeed possible with most lithium-ion cells but only at very low currents. According to research papers, the allowable charge rate at –30
°C (–22°F) is 0.02C. At this low current, the charge time would stretch to over 50 hours. It is for this reason that manufacturers prohibit the charging below freezing.

Specialty Li-ion is available that can charge at temperatures down to –10°C (14°F) at a reduced rate. To charge at a higher rate, Li-ion systems for automotive propulsion systems require a heating blanket. Some hybrid cars circulate warm cabin air through the batteries to raise the temperature. Liquid heating and cooling is the preferred method in high-performance electric cars.


High-temperature Charge

Heat is the worst enemy of batteries, including lead acid. Adding temperature compensation on a lead acid charger to adjust for temperature variations prolongs battery life by up to 15 percent. The recommended compensation is 3mV per cell per degree Celsius applied on a negative coefficient, meaning that the voltage threshold drops as the temperature increases. For example, if at 25°C (77°F) the float voltage is set to 2.30V/cell, the recommended setting at 35°C (95°F) is 2.27V/cell and at 15°C (59°F) 2.33V/cell. This represents a 30mV correction per cell per 10°C (18°F). Table 2 indicates the optimal peak voltage at various temperatures when charging lead acid batteries. The table also includes the recommended float voltage while in standby mode.


Battery status -40°C (-40°F) -20°C (-4°F) 0°C (32°F) 25°C (77°F) 40°C (104°F)
Voltage limit
on recharge
2.85V/cell 2.70V/cell 2.55V/cell 2.45V/cell 2.35V/cell
Float voltage
at full charge
or lower
or lower
or lower
or lower
or lower

Table 2: Recommended voltage limits when recharging and maintaining stationary lead acid batteries on float charge. Voltage compensation prolongs battery life when operating at temperature extremes.

Charging nickel-based batteries at high temperatures lowers oxygen generation, which reduces charge acceptance. Heat fools the charger into thinking that the battery is fully charged when it’s not.

Figure 3 shows a strong decrease in charge efficiency above 30
°C (86°F). At 45°C (113°F), the battery can only accept 70 percent of its full capacity; at 60°C (140°F) the charge acceptance is reduced to 45 percent. NDV for full-charge detection becomes unreliable at higher temperature and temperature sensing is essential for backup. Newer NiMH performs better at elevated temperatures than NiCd.


NiCd charge acceptance as a function of temperature.

Figure 3: NiCd charge acceptance as a function of temperature. High temperature reduces charge acceptance. At 55°C, commercial NiMH has a charge efficiency of 35–40%; newer industrial NiMH attains 75–80%.

Courtesy of Cadex

Lithium-ion performs well at elevated temperatures but prolonged exposure to heat reduces longevity. Some lithium-based packs must momentary be heated to high temperatures and this applies to batteries in surgical tools that are sterilized at 137°C (280°F). Oil & gas drilling as part of fracking are exposed to similar high temperatures.

Capacity loss at elevated temperature is in direct relationship with state-of-charge (SoC). Figure 4 illustrates the effect of Li-cobalt (LiCoO2) that is first cycled at room temperature (RT) and then heated to 130°C (266°F) for 90 minutes and cycled at 20, 50 and 100 percent SoC. There is no noticeable capacity loss at room temperature. At 130°C and a SoC of 20 percent, a slight capacity loss is visible over 10 cycles. This loss is higher at a SoC of 50 percent and shows a devastating effect when cycled at full charge.

Batteries in surgical power tools should be sterilized at low SoC. This also reduces the danger of a thermal runaway as the threshold is lower compared to one that is fully charged. (See BU-409: Charging Lithium-ion under Overcharging Lithium-ion.)


Capacity loss
Figure 4: Capacity loss at room temperature (RT) and 130°C for 90 minutes
Sterilization of batteries for surgical power tools should be done at low SoC.

Test: LiCoO2/Graphite cells were exposed to 130°C for 90 min.at different SoC between each cycle.
Source: Greatbatch Medical

Caution:  In case of rupture, leaking electrolyte or any other cause of exposure to the electrolyte, flush with water immediately. If eye exposure occurs, flush with water for 15 minutes and consult a physician immediately.

Last updated 2015-11-12

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On January 12, 2011 at 11:02pm
Girish.K wrote:

How to calculate the connected load of battery chargers
360V-150A-80% efficency

On August 24, 2011 at 10:33am
Janusz Konopka wrote:

Battery means several cells connected in series.  I the course of work (after several charging and discharging cycles) one may note important differences between particular cells.  Despite of   monitoring particular cells during discharge it chappens that battery become useless because e.g. one cell is much weaker. I founfd it in the case of my electric bike. After, say, some 30 cycles battery become usless. When I performed separate charging of weaker cells the baterry recovered and could be used again.
Plese give me the approximate internal resistance of Li-Ion cell (dV/dI).  This parameter will may be decisive in controlling quality of each cell.

On October 31, 2011 at 7:48am
Max Dirnberger wrote:

Dear Janusz,

This will be because your charger is not doing charge balancing. When Li-Ion batteries are in series (most battery packs) this step is often not implemented but must be to avoid the problem you mention

On December 24, 2011 at 9:03pm
Omair wrote:

So basically, if I don’t requite the batteries to fast charge, and since I plug my phone to the charger before bed, I actually prefer it to charge slowly in order to reduce stress, wouldnt cooling the phone to about 15°every night
help elongate my battery life? (Accodibg to your other post, by uptill 15%).
The battery in consideration is a 3.7v 1230mAh Li-ion battery.

On March 13, 2012 at 7:23pm
Happy wrote:

So i have already read all the lesson above. my question is which one is the best metode, charging at the lowest or highest temperature for range 10 - 30C that you mentioned?

thanks for the answer

On June 24, 2012 at 6:45pm
jo wrote:


On July 20, 2012 at 3:48am
emad wrote:

I connect my phone to my pc ( tethering to get internet ) about 4 to 5 times last weak and i found that my battery is get fully charge after 2hours connecting to the charger instead of 2h 30min as usual .Is that mean that my battery health is affected too much?
and usualy i connect my charger when my battery charge about 25% : 40%
is it okay , or better to leave it to fully discharge befor charge it agail??
please help
my battery is li-ion 1200
the room temp. about 28° : 30°c

On September 30, 2012 at 11:25am
Garry wrote:

So i have already read all the lesson above. my ­question is which one is the best metode, charging at the lowest or highest temperature for range 10 - 30C that you mentioned?

On December 17, 2012 at 8:29am
Dave Dutton wrote:

I have heard lately from Makita salesman that charging warm is best. How warm? I don’t know. I am thinking that since the Lipos like to discharge at near 100 degrees F that charging might be best near that temperature, too.
Anyone with data? Anywhere? I am studying.

On January 14, 2013 at 2:27pm
Pim wrote:

Can I charge a Li-ion above 40C till 50C? With a voltage of 3,92Volt (50%) without damage the battery?

On May 8, 2013 at 8:43pm
Stephen wrote:

Compare to other type of battery, NiCd gives best performance in charging for temperature over 40 degree C.
High Temp NiCd can doing good at 70 degree C. That is why they still use in Emergency Lighting application.
I can also make Low Temp NiCd which perform 65% at -20 degree C. It is heard that some companies can even supply NiCd work at -40 degree C.
My experience is that, Li-ion battery become unstable when over 40 degree C. It could be dangerous of fire if you get products from unprofessional manufacturer.
0 - 40 degree C is the suitable range for most Li-ion.

On May 29, 2013 at 1:33am
praveen wrote:

can anybody tell me how to calculate battery sizing when the load power is 12KW

On June 29, 2013 at 11:52pm

I have been a keen follower of your site and i have interests i battery manufacturing. Please advise me on factors influencing charge acceptance.

On September 5, 2013 at 5:24pm
dale wrote:

hi i was wondering about batteries will they be a bomb if you put too much heat on it

On September 18, 2013 at 2:03am
Tom Wald wrote:

Wireless chargers for cellphones increase battery temperature. The third party fonesalesman brand QI charger for my Samsung Galaxy S4 takes the battery temperature up to around 37 degrees, maybe a little more for long charges, whereas charging by plugging it in produces a very small temperature rise.

Are there any safety concerns here? Will the battery life be significantly degraded?

On December 15, 2013 at 4:35pm
Oto wrote:

What about alkaline rechargable batteries and NiZn? What are temperature limits for charging?

On December 17, 2013 at 6:31am
stephen wrote:

Special NiCd battery can be charged at temp up to 70°C, this is so called High Temp NiCd, normally used in maintained Emergency Lighting in Europe regulation, especially in UK.
They are in floating charging all the time, and must be over 70% capacity after working in four years.
Another special Low Temp NiCd can work down to -40°C. This is used mostly in cold storage warehouse.
Anyone want to know more can contact me.

On December 18, 2013 at 1:29am
praveen wrote:

@Stephen you have mentioned they are in float charging all the time, so what would be tha max cahrge and discharge rates it can be operated?

On December 24, 2013 at 11:15pm
muhammadmutlab wrote:

q786 low battre tam

On February 14, 2014 at 6:36am
William wrote:

I have a lithium battery in my laptop, I lost my dell charger and have a rocket fish charger which allows my computer to run but it has 0% charge. If my plug is pulled out of the outlet the computer shuts off.

Would putting my battery in the freezer for a couple days be a good idea, pointless, or a terrible idea? A friend told me it can bring back some battery life that has been slowly degrading, is this true?

On June 24, 2014 at 8:36am
Chris Fox wrote:

I have a small solar cell charging two Lithium batteries in series that run a very low power device in an industrial application. The device will normally run a year on four “AA” alkaline cells, so it’s power consumption is very low. The power from the small solar cells is also very small current. What I need is to keep the system running indefinitely with daily sunlight. Can I let the solar cell charge the lithium battery constantly (when there’s light) through a resistance to minimize the current? Because of the very low currents involved, I think the charging current could be microamperes. Would that damage the lithium cells?

On August 29, 2014 at 10:14pm
Ankitha Jayan wrote:

I have a new smartphone, it has a   “Li-Ion 2000 mAh battery”. Should i need to fully charge it before first use…??? Am used my phone while i charging first time . Is there any problem with this…? How can i get maximum life time

On October 18, 2014 at 8:41am
Brian W wrote:

I have a question with regards to the solar charger temperature limits as opposed to the battery temperature limits itself - I’m I’m out camping, say, in the winter, and need to charge my smartphone, as long as I kept the phone/battery w/in its recommended temperature range, would it not matter how cold the solar charger is?

On January 1, 2015 at 1:32am
wajahat wrote:

any softwear who charged the laptop in cold weathr witout electrictcity?

On January 15, 2015 at 11:22pm
BOORA wrote:

I have learnt so much about Li-ion batteries. But thow can we measure/calculate the battery backup after 50% use, If i used the battery with 100%,60% 30% discharge levels.Kindly explain more about this.

On May 17, 2015 at 7:12pm
raju wrote:

What should be the max temperature of electrolyte

On January 19, 2016 at 7:49am
holy wrote:

What is maximum charge of a car battery?