BU-410: Charging at High and Low Temperatures

Batteries operate over a wide temperature range, but this does not give permission to also charge them at these conditions. The charging process is more delicate than discharging and special care must be taken. Extreme cold and high heat reduce charge acceptance and the battery should be brought to a moderate temperature before charging.

Older battery technologies, such as lead acid and NiCd, have higher charging tolerances than newer systems, such as Li-ion. This allows them to charge below freezing at a reduced charge C-rate. When it comes to cold-charging NiCd is hardier than NiMH. Lead acid is also tolerant, but Li-ion needs special care.

Table 1 summarizes the permissible charge and discharge temperatures of common rechargeable batteries. 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%.
Li-ion 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 the 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

Nickel Based: Fast charging of most batteries is limited to 5°C to 45°C (41°F to 113°F). For best results consider narrowing the temperature bandwidth to between 10°C and 30°C (50°F and 86°F) as the ability to recombine oxygen and hydrogen diminishes when charging nickel-based batteries below 5°C (41°F). If charged too quickly, pressure builds up in the cell that can lead to venting. Reduce the charge current of all nickel-based batteries to 0.1C when charging below freezing.

Nickel-based chargers with NDV (negative delate V) full-charge detection offer some protection when fast charging at low temperatures. 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 synonymous.

To enable fast charging at all temperatures, some industrial batteries add 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 is advised to only charge at room temperature.

Lead-acid: 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. When going to –20°C (0°F), the gassing threshold rises to 2.97V/cell.

A lead acid battery charges at a constant current to a set voltage that is typically 2.40V/cell at ambient temperature. This voltage is governed by temperature and is set higher when cold and lower when warm. Figure 2 illustrates the recommended settings for most lead acid batteries. In parallel, the figure also shows the recommended float charge voltage to which the charger reverts when the battery is fully charged. When charging lead acid at fluctuating temperatures, the charger should feature voltage adjustment to minimize stress on the battery. (See also BU-403: Charging Lead Acid)

Cell voltages on charge and float at various temperatures
Figure 2: Cell voltages on charge and float at various temperatures [1]
Charging at cold and hot temperatures requires adjustment of voltage limit.

Freezing a lead acid battery leads to permanent damage. Always keep the batteries fully charged because in the discharged state the electrolyte becomes more water-like and freezes earlier than when fully charged. According to BCI (Battery Council International), 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 with 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 they fade and need replacement.

Lithium Ion: Li-ion can be fast charged from 5°C to 45°C (41 to 113°F). Below 5°C, the charge current should be reduced, and no charging is permitted at freezing temperatures because of the reduced diffusion rates on the anode. During charge, the internal cell resistance causes a slight temperature rise that compensates for some of the cold. The internal resistance of all batteries rises when cold, prolonging charge times noticeably. This also affects discharge performance noticeably with Li-ion.

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 occurs on the anode during a sub-freezing charge that leads to a permanent degradation in performance and safety. 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.

Advancements are being made to charge Li-ion below freezing temperatures. 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, a time that is deemed impractical. There are, however, specialty Li-ions that can charge down to –10°C (14°F) at a reduced rate.

Some Li-ion manufacturers offer custom-made cells for cold-charging. Specialty chargers will also be needed that decrease the C-rate according to temperature and charge the battery to a lower voltage peak; 4.00V/cell rather than the customary 4.20V/cell for example. Such limitations decrease the energy a Li-ion battery can hold to roughly 80% instead of the customary 100%. Charge times will also be prolonged and can last 12 hours and longer when cold.

Li-ion batteries charging below 0°C (32°F) must undergo regulatory issue to certify that no lithium plating will occur. In addition, a specially designed charger will keep the allotted current and voltage within a safe limit throughout the temperature bandwidth. Certification of such batteries and chargers are very costly that will reflect in the price. Similar regulatory requirements also apply to intrinsically safe batteries (See BU-304: Why Are Protection Circuits Needed?)

There are cell and charger manufacturers claiming to charge Li-ion at low temperatures; however, most companies do not want to take the risk of potential failure and assume liability. Yes, Li-ion will charge at low temperature but research labs dissecting these batteries see concerning results.

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 is said to prolong battery life by up to 15 percent. The recommended compensation is a 3mV drop per cell for every degree Celsius rise in temperature. If the float voltage is set to 2.30V/cell at 25°C (77°F), the voltage should read 2.27V/cell at 35°C (95°F). Going colder, the voltage should be 2.33V/cell at 15°C (59°F). These 10°C adjustments represent 30mV change.

Table 3 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/cell2.45V/cell2.35V/cell
Float voltage
at full charge
2.55V/cell
or lower
2.45V/cell
or lower
2.35V/cell
or lower
2.30V/cell
or lower
2.25V/cell
or lower
Table 3: Recommended voltage limits
when charging 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.

Charging nickel-based batteries when warm lowers oxygen generation that reduces charge acceptance. Heat fools the charger into thinking that the battery is fully charged when it’s not. Figure 4 shows a strong decrease in charge efficiency from the “100 percent efficiency line” when dwelling 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 temperatures, and temperature sensing is essential for backup.

NiCd charge acceptance as a function of temperature
Figure 4: NiCd charge acceptance as a function of temperature [2]

High temperature reduces charge acceptance and departs from the dotted “100% efficiency line.” At 55°C, commercial NiMH has a charge efficiency of 35–40%; newer industrial NiMH attains 75–80%.

Lithium-ion performs well at elevated temperatures but prolonged exposure to heat reduces longevity. Charging and discharging at elevated temperatures is subject to gas generation that might cause a cylindrical cell to vent and a pouch cell to swell. Many chargers prohibit charging above 50°C (122°F).

Some lithium-based packs are momentarily heated to high temperatures. This applies to batteries in surgical tools that are sterilized at 137°C (280°F) for up to 20 minutes as part of autoclaving. Oil and gas drilling as part of fracking also exposes the battery to high temperatures.

Capacity loss at elevated temperature is in direct relationship with state-of-charge (SoC). Figure 5 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 with a 20 percent SoC, a slight capacity loss is visible over 10 cycles. This loss is higher with a 50 percent SoC and shows a devastating effect when cycled at full charge.

Capacity loss at room temperature (RT) and 130°C for 90 minutes
Figure 5: Capacity loss at room temperature (RT) and 130°C for 90 minutes [3]
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.

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.

References

[1] Source: Betta Batteries
[2] Courtesy of Cadex
[3] Source: Greatbatch Medical

Last Updated: 1-Mar-2022
Batteries In A Portable World
Batteries In A Portable World

The material on Battery University is based on the indispensable new 4th edition of "Batteries in a Portable World - A Handbook on Rechargeable Batteries for Non-Engineers" which is available for order through Amazon.com.

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Jeff

Are these ambient temperatures or actual internal battery temperatures? And what's the correlation between the two? If 25C is optimal ambient temperature for charging is there an optimal internal battery temperature at 25C ambient? Is the ideal battery temp 25C when ambient is 25C? 30C? 35? 40?

Prince

You can read about the boat batteries here: https://sailorsknowit.com/can-you-use-deep-cycle-battery-for-starting-boat/

Jim Weslock

I understand the theory behind not charging 18650’s at or below freezing.
Can this work, I have my power wall 14s120p located in a separate small shed which located away from the main house and a separate backup to my main lead acid system in the main house. Temps in the Canadian winter here drop below freezing for several months Dec-April. Use of this power is needed as the PVs and sun exposure on the main are reduced.

Can I heat the shed using a generator to raise the lithium batteries to a temp of 10-15C start once reached start charging the lithium’s using the generator to 70-80% SOC shut the generator down and use the batteries until they reach my lbco of 3.3volts?
Repeat the process as needed.

I realize it seems inefficient but I will be able to determine how much usage (5 amps an hour) I can get out of each cycle until the temps come back up in the spring and make a judgment to continue with the cold charge cycle further the next fall.

Zion

What is the reason that the electrolyte in a dicharged lead storage battery free
zes at higher temperature than a fully charged battery?

Zion

What is the reason that the electrolyte in a dicharged lead storage battery free
zes at higher temperature than a fully charged battery?

P. Ramanathan

Can a LiFePO4 battery, 24 V, 60 Ah be efficiently charged under Constant Voltage charge source (Genarator, 28 V, 8 kW) without current control?
Will be the CV charge effective with inbuilt Arctic heater at temperatures below -20 degree Celcius?

P. Ramanathan

Can a LiFePO4 battery, 24 V, 60 Ah be efficiently charged under Constant Voltage charge source (Genarator, 28 V, 8 kW) without current control?
Will be the CV charge effective with inbuilt Arctic heater at temperatures below -20 degree Celcius?

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On March 9, 2019, Steve Balinski wrote:
Several takeaways here and concerns. If using one of these in a car, in a location like Chicago which has 100deg summers and -deg winters. Concern 1: Li-ion must not dip below 2V/cell for any length of time. Copper shunts form inside the cells that can lead to elevated self-discharge or a partial electrical short. If recharged, the cells might become unstable, causing excessive heat or showing other anomalies. Is this most likely going to happen here? Concern 2: no charging is permitted at freezing temperatures because of the reduced diffusion rates on the anode. Obviously the Alternator is going to try and charge them when its cold out... 1. is my car even going to start, 2, what happens when the ALT starts charing the cells? How are these used in cars given that all these conditions will apply depending on location?? 3. Many articles on building battery packs say they discharge the batteries, and then slowly recharge them with a BMS....If they discharge them below 2V, doesnt this automatically put them in a volatile state? Am I missing something?
On August 14, 2018, Pauli A. wrote:
Finland / Loviisa has had some 55 days in row with temperatures at plus 30 C or more.In January we have spells up to minus 25 C. Born 15,08.1935 I made myself a promise: Upon arrival of my sonomotors.com Sion Solar car I will carry a one year test related to battery/ outdoor temperature. My Garage has 16 C in the winter, but I can charge/ heat the car with 16A, 11 kW or 22kW at home. Design a test program for my iPad and you will get the report free of charge. Let me know your interest right away, but there is plenty of time to plan the tests programme.
On May 11, 2018, Pauli wrote:
rejoining thread
On May 10, 2018, Carlo wrote:
In hot countries (28-34C ambient temps), has anyone tried to immerse lead acid batteries in a water bath, say up to 3/4 of the battery’s height, in an attempt to lower ambient temp and increase life? I have this crazy idea of a recirculating Water bath using a small fountain pump to circulate water on the exteriors of a 2-Battery bank. Comments?
On March 28, 2018, Paul wrote:
I have a file on batteries on my early PC stipulating the optimal working temperature to be 21 Celsius. Do you agree or have another figure?
On March 23, 2018, Martin wrote:
I received a notice there was a response but i cannot find it. Are the responses displayed on this page? Thanks!
On March 22, 2018, Martin wrote:
I want to replace my lead acid batteries with lithium, my challenge is that winter temperatures will get to - 30 c. We will not be using the batteries during the cold times as it is a summer/fall season cottage. If the batteries are not used and disconnected from the cottage, will the cold temperatures affect or damage the lithium batteries once we return in the sping when temps are abou 12 - 20 c? Thanks!
On January 2, 2018, Vignesh Ananthan wrote:
I am seeing that most of the Li-Ion battery data sheet are saying the max allowable temperature during charging is 45degC. Is the maximum operating temp during charging having any relation with charging current as below? Max oper temp with 1amp charging current is 45degC Max oper temp with 0.9amp charging current is 46degC Max oper temp with 0.8amp charging current is 47degC Max oper temp with 0.7amp charging current is 48degC and so on. If yes, can you please give the formula to calculate this?
On December 30, 2017, Claude Courchaine wrote:
Hi, Compliments to Cadex and all who participate on this most educational and enjoyable site! I have not (yet) come across information regarding the charge acceptance rate of a typical automotive "sealed" lead acid in use below -20C. It is understood that the temperature of the battery will increase with underhood teperatures, thus conforming with the 0.3C charging above -20C, but what happens at less than -20C - which can occur in typical northern climate with short drive cycles? After such cold starts, the car computer's voltage readout appears to be over 14+volt, even immediately after start in -30C weather (amperage rate unknown). Is there a cutoff where the battery is not being charged? Thank you for any further information. Regards, Claude
On November 17, 2017, mrinal mani wrote:
Hi! What temperature are we talking about, surface temperature or ambient temperature? Consider a typical 18650 Lithium cell that has a maximum 45 degree C limit during charging. Is 45 degree C the surface temperature of the cell or the ambient temperature? Thanks
On July 19, 2017, DURGAMADHAB MISHRA wrote:
Sir/Madam, I want Temperature Vs Charging & discharging graph of LI(lithium Ion) battery. Please support in sharing. Can anybody share how LI battery pack is better than VRLA battery in auto-mobile application.
On June 22, 2017, Jason Han wrote:
Yasir. Try to use evoparative cooling method. Example. Put your battery in plastic bag, put them in a shallow pail of water. Make sure water doesn't go into the battery.
On June 7, 2017, Christopher de Vidal wrote:
Yasir maybe duct air from a cooler location. Some fans.
On June 4, 2017, Yasir wrote:
My location temperature is 35 to 45 degree centigrade,we use gas generator for power source.as generators produce lot of heat and the battery is also placed near by.so the temperature around the battery is near 60 centigrade.rate of acid evoparation is high.how I keep the battery cool.
On April 8, 2017, Christopher de Vidal wrote:
Does anyone have a link to the research papers for this quote? I couldn't find anything. "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."
On March 19, 2017, Rob Gilbert wrote:
I keep my lithium drill batteries in my shed which gets very hot in the peak summer.Can anyone tell me if this is a hazard for lithium batteries or is is just direct sunlight that causes a hazard? One of my batteries has a 30 degree marking on the label, this seems very low to me as a maximum temperature. I would think the inside my shed gets to 40 degrees or even a bit more in peak summer. What is the maximum safe temperature a drill lithium battery can be kept at before there is risk of fire/explosion?.
On January 13, 2017, Md jiauddin wrote:
My betry temperature is high charge can't be phone
On June 28, 2016, Zsean wrote:
I am making a device which uses a dc heater with a builtin battery the heater runs from battery and the heater and the battery is adjacent to eachother the heat produced will damage the battery how can i prevent the battery from damaging....
On March 24, 2016, jheandianesanjuan wrote:
Plus help me how to use my cellphone because when I plug it in the outlet it shuts down.. and when I charged it off it s just0%all day long???what will I do.. pls hep le
On March 24, 2016, jheandianesanjuan wrote:
What if I do if when I pku my phone.. it shuts off and when I charged it in the outlet.. it just 0%all day long..
On January 19, 2016, holy wrote:
What is maximum charge of a car battery?
On May 18, 2015, raju wrote:
What should be the max temperature of electrolyte
On January 16, 2015, 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 January 1, 2015, wajahat wrote:
hi any softwear who charged the laptop in cold weathr witout electrictcity?
On October 18, 2014, 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 August 30, 2014, 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 June 24, 2014, 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 February 14, 2014, 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 December 25, 2013, muhammadmutlab wrote:
q786 low battre tam
On December 18, 2013, 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 17, 2013, 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 15, 2013, Oto wrote:
What about alkaline rechargable batteries and NiZn? What are temperature limits for charging?
On September 18, 2013, 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 September 6, 2013, dale wrote:
hi i was wondering about batteries will they be a bomb if you put too much heat on it
On June 30, 2013, GILBERT M. SAMOITA wrote:
Hi, 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 May 29, 2013, praveen wrote:
can anybody tell me how to calculate battery sizing when the load power is 12KW
On May 9, 2013, 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 January 14, 2013, Pim wrote:
Can I charge a Li-ion above 40C till 50C? With a voltage of 3,92Volt (50%) without damage the battery?
On December 17, 2012, 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 September 30, 2012, Garry wrote:
So i have already read all the lesson above. my <a href="http://www.teletechnology.in/">­</a>question is which one is the best metode, charging at the lowest or highest temperature for range 10 - 30C that you mentioned?
On July 20, 2012, 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 June 25, 2012, jo wrote:
Hi
On March 14, 2012, 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 December 25, 2011, 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 October 31, 2011, 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 August 24, 2011, 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 January 13, 2011, Girish.K wrote:
How to calculate the connected load of battery chargers 360V-150A-80% efficency