http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries
Simple Guidelines for Charging Lithium-based Batteries
* A portable device should be turned off while charging. This allows the battery to reach the threshold voltage unhindered and reflects the correct saturation current responsible to terminate the charge. A parasitic load confuses the charger.
* Charge at a moderate temperature. Do not charge below freezing.
* Lithium-ion does not need to be fully charged; a partial charge is better.
* Chargers use different methods for “ready” indication. The light signal may not always indicate a full charge.
* Discontinue using charger and/or battery if the battery gets excessively warm.
* Before prolonged storage, apply some charge to bring the pack to about half charge.
* Over-discharged batteries can be “boosted” to life again. Discard pack if the voltage does not rise to a normal level within a minute while on boost.
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Comments
On November 10, 2010 at 3:39am
Adley wrote:
Super post there! Comprehensive and well collated material. Thanks for sharing.
On November 11, 2010 at 7:41am
Grosser wrote:
Very usefull information here, good thing I fond this page first before designing a charger for my custom-made battery pack.
P.S. You’re alwais talking about a 4,2V like they are the the standardwhat about 3,6V cells?
On November 12, 2010 at 3:52pm
Jason wrote:
Facinating stuff, although I doubt I will ever have the ambition to put it use.
On November 21, 2010 at 6:45am
Mike wrote:
Grosser,
3.6 is the nominal delivery voltage of a Li-ion cell, while 4.2 is the max charging voltage. They are the same battery. It’s the same situation with other battery chemistries, e.g. for a 12V lead-acid battery, you’d be charging to ~14V
On November 21, 2010 at 7:22pm
Paul Smith wrote:
My Li-ion battery is used in a Canon 50D DSLR camera; The charger blinks to indicate the level of charge. The indications are 1-blink series, 2-blink series, 3-blink series, and steady-on to indicate full charge. Often I leave the battery in the charger and go to bed if the LED is at the 2-blink state. When I wake up 4 to 5 hours later, the LED may have been steady-on for 4 hours. I have two questions. (1)What harm am I doing to my battery by following this practice and (2)Is the battery fully-charged if I remove it from the charger as soon as the steady-on state is reached?
On November 22, 2010 at 8:15am
Eduardo wrote:
I need to do the following test:
1 Question;
Have my charge Battery is Full. How time (day) can battery disconnect?
and
2 Questions
What time need battery recharge for has charge Full ?.
PD: My power Supply is 3,7 volt
On November 23, 2010 at 6:26pm
MANAS R. PANIGRAHI wrote:
what is the work of that circuit inside a lithium ion battery?
On November 24, 2010 at 7:29am
Eduardo wrote:
Thak You, unanswer.
The Batery is connected circuit 3,6 volt constant (regulable according to load) and this support a circuit for memory and a processor primary.
Thanks again.
Eduardo
On December 2, 2010 at 1:12am
Steve Webert wrote:
Does it benefit a lithium-ion or lithium-ion-polymer battery to periodically discharge it “fully” (ie, down to the above mentioned 2.7V-3.0V range)?
I have read several OEM’s offering differing strategies for optimizing battery life.
Thank you for your time and efforts—I very much appreciate the above instruction.
On December 9, 2010 at 2:02pm
Thomas Vargas wrote:
What about chargin vehicle batteries? This will be a big issue if they ever become popular.
How would the graph look if it were for vehicles?
On December 17, 2010 at 8:43pm
thomas micciantuono wrote:
Can lithium polymer cell phone batteries be over charged if left on charge to long and if left on to long will it diminish battery life.
On December 27, 2010 at 9:27pm
Andy wrote:
I’ve inherited an electric vehicle powered by two 38V/90Ah lithium-ion batteries. The voltage of both packs read around 9V only! The engine management system reports that a mere 21 hours of operation have been logged thus far. Are these battery packs truly dead-DEAD or is it possible to resuscitate them again in one way or another? Please advise. Cheers.
On January 3, 2011 at 10:21pm
Flynn Siy wrote:
I am looking for alternative charges for my HTC Desire. The standard charger that came with it is 5V and 1000mah. Since the charger uses a standard micro USB tip, there are a lot of available chargers out there with different Amp rating. Is it advisable to get a low Amp rating such as 500mah, higher amp such as 1200mah or stick with the same 1000amp? Is slow charging better than fast charging?
On January 6, 2011 at 12:50am
Jerry Conrad wrote:
My HTC EVO cellphone shuts down when the discharge voltage reaches 3.6 volts. Isn’t this reducing the use-capacity of this battery quite a bit?
On January 6, 2011 at 9:59pm
Jovy Macaspac wrote:
I’ve read somewhere that a charger with a lower voltage rating (e.g., 3.2v) cannot recharge a lithium battery with a higher voltage rating (e.g., 3.7v). Is this true? Something to do with electron transfer, I think… If this is true, I’m confused. How can a 3.7v charger charge a 3.2v battery to 4.2v if, when they reach the same voltage level (3.7v), it can no longer push said electrons around the battery?
Another question, if it’s alright: USB chargers have a rating of 5v. Would this cause problems with lithium batteries since as stated above, charging above 4.3v causes plating of the metallic lithium on the anode?
Thanks and more power!
Jovy
On January 7, 2011 at 6:47pm
Mr. D wrote:
how can you trickle charge a 12v batt @ 2v trickle and get a full charge . the battery is like a tank, with a limitation of it"s rateing ie. 4.2v or 12v ,is the limit that the battery will hold, forceing anything over that will start to burn the core of the battery in one way or the other ... do i win a cuppie doll??
On January 9, 2011 at 1:44pm
Vass wrote:
@ Flynn Siy, the ratings of the charger mentioned misguiding me as the standard charger rating should be in terms of volts and Amps/milli amps(mA) but not in mAh. If your concern is about a charger(i’ll interpret it to 500mA/12mA ) then go for 1200mA. There’s no harm in it. If you go for 500mA, it’ll charge but it become hot due to it’s inability to supply the rating current(say 1000mA).This inturn drop the voltage. If your concern is about a battery(a standard battery rating will be in volts and mAh), go for either one but in reduction in back up, in case if you chose 500mAh.Hope it cleared your doubt.
Cheers,
Vass.
On January 12, 2011 at 7:03am
Shiwakoti wrote:
How Li-ion battery gets recharged? Why at elevated temperature the battery life gets shortened? Does frequent charging pratice without being fully discharged affect bttery life span? Plz help..
On January 15, 2011 at 3:55am
Ike wrote:
“My HTC EVO cellphone shuts down when the discharge voltage reaches 3.6 volts. Isn’t this reducing the use-capacity of this battery quite a bit?”
—This is to protect the battery: further discharge could destabilize it and next charging could be risky (you may have heard of exploding LiIon batteries…).
Despite more strict cutoff liit, LiIons can store more energy than previous technologies iin same cell size, so you should not consider this a design fault/drawback, just a essential characteristic feature of this different chemistry.
—
Shiwakoti, you will find answers to your questions on the articles at this site: esp. in “Is lithium-ion the ideal battery?”. Shortly said, elevated temperature speeds up battery aging (it’s a chemical reaction a bit like how iron rusts faster in humid climate compared to dry circumstances) and it’s MUCH better to recharge often than let LiIons drain fully.
On January 15, 2011 at 5:43am
Shiwakoti wrote:
Thanks for the answer..
On January 23, 2011 at 1:08am
STEYAERT.DANIEL wrote:
GOED UITGELEGDE TEKST
On January 23, 2011 at 1:31pm
Curt Eglin wrote:
Excellent material. I now know how to properly charge a 3.7 volt Li-Ion pack I took out of a Blackberry phone that is since defunct. Tnx.
On February 2, 2011 at 2:24pm
Mike wrote:
So in this article is states that Lithium Ion batterys are charged upto 4.2v, where each cell can handle 4.2v +/- .05v. So the upperbound here is 4.25v to 4.15v. So, if you have a charger that is push the cells to 4.21v or 4.22v, then it is theoretically fine.
“A continuous trickle charge above 4.05V/cell would causes plating of metallic lithium that could lead to instabilities and compromise safety. “
Here though you say that raising the cell above just over 4v may cause plating. So by specification, charging lithium ion cells to 4.2v will cause plaiting?
On February 4, 2011 at 6:54am
captainirmak wrote:
i observe (via an application) that my smartphone is reaching till 4191 volts during re-charging the battery by usb cable.
can we say that battery is died a bit? cos it is not reaching 4.2 or above.
i know that it is very small numbers but curious about it.
and also what shold i do max charge the battery?
On February 4, 2011 at 2:21pm
Ken wrote:
The article mentions how dangerous it is to attempt charging cells that have been @<1.5v for just a few days. Well, that has not been in agreement with my experience. I occasionally salvage discarded Li-ion laptop battery packs…disassembling them to harvest the 18650’s for personal r/c and flashlight use. I commonly pull cells that are totally flat: 0v, sometimes even with polarity reversed by a few millivolts. In addition, some of the battery packs I ripped into were prehistoric by lithium chemistry standards (10 years+). More often than not all cells would recharge to their FULL original rated capacity and perform as new. I always test each cell individually with my iMAX B6 charger, manually putting them through at least a couple 500mA to 1Amp discharge/charge cycles. I have *never* experienced any safety nor reliability issues to date.
I would also like to brag of having had success restoring substantial capacity to the occasional cells that truly were worn. I will never share my method_IT’S MINE !_do not ask. ...Additionally, that procedure IS potentially dangerous and requires mandatory attentive supervision.
I suppose I’ve been laughing all the way to the battery bank. I know, horrible joke!
On February 11, 2011 at 1:30pm
TAS wrote:
What i have believed is keeping my laptop plugged in all the time at my desk and using the battery power in case of power failure or so. We have very frequent power cut-downs for brief spans. I also use BatteryCare to notify me of recalibration.
AFAIK Li-ion does not have memory effect and they have PMS circuit built-in so don’t overcharge.
A vendor of notebooks recently opposed and recommended to cycle discharges and recharges regularly to keep the battery healthy and prolong its life.
What’s the bottom line?
On February 11, 2011 at 1:32pm
tas wrote:
What i have believed is keeping my laptop plugged in all the time at my desk and using the battery power in case of power failure or so does no harm to my battery pack. We have very frequent power cut-downs for brief spans. I also use BatteryCare to notify me of recalibration.
AFAIK Li-ion does not have memory effect and they have PMS circuit built-in so don’t overcharge.
A vendor of notebooks recently opposed and recommended to cycle discharges and recharges regularly to keep the battery healthy and prolong its life.
What’s the bottom line?
On February 15, 2011 at 10:28am
Steven Hess wrote:
I just bought a Bushnell GPS and it has a Li-Ion battery pack. The instructions said to charge the li-Ion batteries for four hours. But upon plugging the charger to the batteries the green light immediatley came on, indicating a fully charged pack. But the pack is not charged at all. The unit will not turn on with these batteries. So my question is; Why is the charger displaying a Green LED when in fact the batteries need charged. And is there something I can do to make it start charging because the charger doesn’t charge when displaying a green light.
On February 15, 2011 at 1:06pm
Dan wrote:
Mike, I have been thinking of doing some EV experiments using some old laptop cells. They flat and packaged in plastic bags. What do you think about using this type of cell?
On February 16, 2011 at 12:24pm
Edward wrote:
i got a new phone. and it says b4 i do anything, i need to charge it for a total of 12 hours for it 2 run right, and battery life, blah blah…. but my question is, simple and plain… do i need to really charge it for the full 12 hours? can i just charge it until it says 100% charged, which would be in a hour or two…. i’ve google’d my question, and i’ve read mixed answers… “yes you should” “no, you don’t have to, because its a lithium-ion” whoop this, and whoop that…..
i would jus like a simpe answer.. yes or no… and why?
Thanx yous
On February 16, 2011 at 11:49pm
Samer wrote:
hi, i would like to know about the first charge lithium baattery ?
should i live chargim for 24h ?
thanks
On February 18, 2011 at 2:43am
Betty wrote:
Thanks so much. All the new gadgets (laptops, cell phones, portable TV-DVD kits, etc) don’t specify anything about the Battery “rules’ like they used to in the day of NiCad and NiMH. This article is very VERY informative and helpful. NOW, i better start unplugging my laptop… thought i was ‘saving’ the battery by keeping it plugged in while using. I guess i probably shouldn’t be charging my cell phone overnight for 8+hours either?
On February 19, 2011 at 2:33am
Ken wrote:
Great article, very informative. Can anyone help me with the following:
I have a Gibson Robot Guitar, the manufacturer states that it runs on:
(2 x 14500) 2.4v 2100mAh lithium rechargeable battery system.
These batteries have been run down for some time now and do charge, the manufacturer cannot replace them.
How can the voltage be 2.4v when the minimum cell voltage for lithium batteries is 3.6v What should I buy to replace these?
On February 25, 2011 at 9:12pm
marwan saade wrote:
dear sir
i have a vemar jiano helmet with integrated bluetooth. by mitake i’ve charged it with a nicd charger so the batterie was distroyed and does not work anynore.
when i opened the divice i found a li ion battery 3.7v 800ma reference stilo b001011.
please i would like to know if there is a way to fix it or recharge it again
if not can i use a a 1cell lypo battery to replace it
On February 28, 2011 at 11:14pm
to make money forex trading wrote:
You made some respectable points there. I looked on the internet for the issue and located most individuals will associate with together with your website.
On March 1, 2011 at 9:19am
BJ McGeever wrote:
So should I do my best to keep the battery at 40%? For instance I’ve been letting it hover around 40% by continually plugging and unplugging it. Is that a good idea?
On March 3, 2011 at 6:08pm
EDWARD BRIDGEWATER wrote:
IS IT POSSIBLE TO CHARGE A PACK OF SIX 1.2 LI-ION BATTERIES WITH THE ORIGANAL
CHARGER THAT WAS BUILT FOR CHARGING A PACK OF 6 1.2 BATTERIES
THE BATTERY PACK IS FOR A SCREW/DRIVER DRILL
I WOULD BE VERY GRATFULL FOR ANY HELP
EDWARD.
On March 10, 2011 at 2:31pm
Isidor wrote:
This article has been updated as of March 10, 2011 with all new information. Enjoy!
On March 10, 2011 at 8:07pm
Robert wrote:
Nice work Isidor. Thank you.
On March 12, 2011 at 10:10am
Lee Kunkiw wrote:
Mar. 13, 2011
To : Robert
I am looking for a 24V bicycle dynamo.
Is it available ? Please help me if you possible.
Thank you.
kunkiw77@gmail.com
On March 15, 2011 at 11:47am
TAS wrote:
What i have believed is keeping my laptop plugged in all the time at my desk and using the battery power in case of power failure or so does no harm to my battery pack. We have very frequent power cut-downs for brief spans. I also use BatteryCare to notify me of recalibration.
AFAIK Li-ion does not have memory effect and they have PMS circuit built-in so don’t overcharge.
A vendor of notebooks recently opposed and recommended to cycle discharges and recharges regularly to keep the battery healthy and prolong its life.
What’s the bottom line?
On March 17, 2011 at 8:22am
Subbu wrote:
Hi,
I have a simple ARM7 gadget and I want to run it on the Li-ion batteries which are available cheap. Is there any singly IC chip solution which could
a. Charge the battery when connected to mains/ USB
b. Indicate the content of charge to ARM7 (ARM7 can query and stop working if there is no charge left to function properly)
With best regards,
Subbu.
On March 25, 2011 at 6:44pm
Francisco Bolivar wrote:
I have an elerctric bike with a 600w - 36v motor.
It uses a li-Ion battery.
Usually each time I use the bike its charge drops about 20% of the total battery charge.
WHAT IS BETTER DO DO:
1 - CHARGE THE BATTERY EACH TIME I USE THE BYKE (battery with 80% of charge)
2 - CHARGE THE BATTERY ONLY WHEN IT REACHS 60% OR 40% OF CHARGE
On March 27, 2011 at 3:02pm
JimQ wrote:
I would like to make a battery pack charger for 4 Li ion cells. Would it be detrimental to limiting the charger voltage to ..say..15 volts. This would be within the voltage limit for each cell if the distribution is even.. However, if a cell is shorted there wpuld be excessove voltage on the other cells in the series string. Would it be better to design the charger for 4.0 volt peak and charger the 4 cells in parallel?
On March 28, 2011 at 7:20am
Dominic Gill wrote:
Excellent article. Thanks.
On March 30, 2011 at 1:00pm
MICHEL KUN wrote:
to
kunkiw77@gmail.com
most dynamo give an AC ourput,
you could try to use a transformer to UP the voltaje
Michel Kun
On March 31, 2011 at 11:47am
Hemanth wrote:
How to remove the charging time li ion battery ? Is there any alternatives way ?
On April 10, 2011 at 12:22pm
Wayne Robey wrote:
Informative article but the voltage drop in stage 3 would indicate a cell in poor condition. A good cell will drop less.
My observation on using batteries after being badly discharged:
About 5 years ago I purchased 40 nearly unused 18X65 cells in 2 cell packs with protect circuit. They ware all discharged to cell voltages of .01 to 1.1 v. I charged them for 10 hrs at c/100 (Now I think c/10 would be OK) and 10% failed shorted. The remainder charged well at c/10 to 4.2 V. Letting them set 24 hrs, I looked at the voltage drop and classified the lowest 10% as weak. Then making a 12 V pack from the remainder I had 2 unused cells classified as good. I have had no failures though they have not been treated roughly. I checked the voltage on the unused cells today. Those marked weak are above 3.7V and those marked good are above 3.9V.
On April 11, 2011 at 4:33am
michael dalton wrote:
Hey guys,
Just want to get this clear in my head. When charging the battery up, I get a controller to put constant current into the battery, then when I sense 4.2v/cell, I get the controller to go into constant voltage (of 4.2) mode and the current will die away naturally till fully saturated?
Cheers
MD
On April 11, 2011 at 7:42pm
Wayne Robey wrote:
Michael, NO, the manufacturer recommends that when 4.2 v is reached, let the current fall to c/10 then turn it OFF. I think a constant voltage charge can be done but it takes a long time and must be done at a lower voltage. When the above charging is done and the battery sits 12 hours, measuring the voltage and setting the float voltage to that is safe and gives maximum capacity but that voltage goes down as the battery ages. A float voltage of 4.1 is reasonable to get best capacity but as the battery gets old, that MIGHT make it age faster. Using the 2 step process of charging at 4.2 v till the current reaches your chosen value (>= c/10) then dropping the voltage to a float value would be the way to quickly charge then float it.
On April 12, 2011 at 4:54am
michael dalton wrote:
Hey Wayne,
Thanks for the reply. So is the current we are measuring the battery current or the current from the charger.
MD
On April 12, 2011 at 5:13am
michael dalton wrote:
Hey sorry Wayne I think I’m becoming confused. Do you apply a constant voltage in stage 2 until the current reaches c/10 OR manually bring the current down to c/10 with a controller?
Cheers
MD
On April 12, 2011 at 5:55pm
Erik wrote:
Why can the the battery pack in a Tesla automobile be charged considerably faster when the charging unit is 240v vs. 110-120v?
I iam a complete novice, and am wondering if higher voltage input decreases charging time.
Thanks for any insight you can offer.
On April 13, 2011 at 5:55pm
Wayne Robey wrote:
Michael,
Not all Li cells are the same so the numbers I use below are for the most common ones, some can be charged much faster.
The algorithm is to check the voltage and if it is < ~3 charge at no more than c/10. If it is >3v charge with limits of c/2 and 4.2 volts until a current of c/10 is reached, then stop . As mentioned in the article a voltage < 4.2 increases battery cycle life, shelf life, and reduces discharge capacity for the current cycle. A charge rate < the maximum rated is easyer on the battery. I think charging with variable current is satisfactory if current is limited as specified on the data sheet and the voltage is limited to 4.1 volts. This is good for float charging and charging from a variable source.
Erick
There is no inherent reason. It was designed that way to account for commonly available power connections, commonly limited to 20A (use at < 80% of limit) at 120v but commonly available at 50 A or more at 240V.
On April 14, 2011 at 12:47am
Jayk wrote:
I am unable to decide which is better - to select a Li-ion battery pack with multiple cells or single cell. For example, how to choose between a 3.7V, 1500mAhr and a 7.4V, 1500mAhr ?
On April 18, 2011 at 9:41am
MICHEL KUN wrote:
i am
CONFUSED
got some PSP battery from HK
I measuered 4.8 volts on end of charge
4.5 volts after 3 days standing
THEN WHY IS 4.2VOLTS MAXIMUM in all litterature
is this value ABSOLETE???
the battery seem to work OK.
thanks in advance for any help or informations
On April 21, 2011 at 4:37am
Alex wrote:
Amazing website… well written .. very very useful
Great Job
On April 24, 2011 at 8:33pm
nash wrote:
Great article!!
On April 25, 2011 at 6:54am
zz wrote:
what happens if you let a li-ion battery connected indefinitely at 4.0V?
On May 3, 2011 at 2:36pm
Ryan wrote:
So I am building a solar powered usb charger for an android device. I know that my available curent and voltage at the time of charging will vary depending on the panel so in addition to overcharging I am wondering if capacitors to buffer power is necessary. I have also considered a 3000mAh battery with an integrated charging circuit would be better. That would offer me more consistent ouput to the device and be a contingency for a lack of or poor lighting. Any ideas would help. Kudos on the page, very informative.
On May 5, 2011 at 8:02am
Bilal nasir zargar wrote:
i brought a new battery sony lithium-ion NP-BG1, WHEN I BUY IT , IT WAS IN SLEEPING MOOD, i plugged the charger for charging, but it did not charge, so please suggest me what should i do…
On May 7, 2011 at 9:19pm
mike wrote:
Great article. Well written and very informative - just what i was looking for. Thanks and keep up the excellent work.
On May 8, 2011 at 8:35am
JimQ wrote:
Great informative article. For a “12volt” pack, I would charge 3 or for Li Ion cells with a constant current source and limit the volts per cell by connecting a 4.0 volt zener diode across each cell. This would allow parallel charging but also protect the cells from ‘over voltage’. Does this make sense? The total charging current would be limited by the charging source circuitry and shut off after all cells reached 4.0 volts.
On May 9, 2011 at 1:08pm
TONY wrote:
Li-Ion (Poli)bat
Min V=2.7V ? 3.0V
Midle=3.6-3.7 (Li-Ion Li-Pol)
end of Charging 4.2V Sel Kill 4.3V+
Kill it Fast 4.35 +
On May 9, 2011 at 1:41pm
MICHEL KUN wrote:
what about voltajes for
LiFePo4
thanks
On May 9, 2011 at 1:51pm
TONY wrote:
Higher charge voltages boost capacity but lower cycle life and compromise safety.
Li-ion battery to 4.20V/cell. This allows maximum runtime
We have limited information by how much lower charge voltages prolong battery life; this depends on many conditions, as we have learned. What we do know, however, is the capacities. At a charge to 4.10V/cell, the battery holds a capacity that is about 10 percent less than going all the way to 4.20V/cell. In terms of optimal longevity, a charge voltage limit of 3.92V/cell works best but the capacity would be low. Besides selecting the best-suited voltage thresholds, it is also important that the battery does not stay in the high-voltage stage for a long time and is allowed to drop after full charge has been reached.
V4.20 end of Charging 100 MA (Panasonic ?)
On May 9, 2011 at 2:04pm
TONY wrote:
4.20 400+ capacity 80%
4.25 400 bat capacity 25%
4.3v 250 Cycles 50%
4.35v 190 Cycles 25%
On May 12, 2011 at 4:07pm
Skip wrote:
My laptop has a battery rated at 10.8V, 85Wh, 8800mAh. The charger outputs 18.5V, 3.5A, and 65W. I have an old charger that is rated 19V, 3.4A and 65W. Would it be safe to use the old one?
On May 13, 2011 at 1:38am
Andrea wrote:
Hi,
i want to charge a 7.5 v 400 mAh li-ion battery from a small solar panel (6V - 1W).
I would connect the solar panel and the battery with a voltage regulator or with a MPP circuit that fixed the output voltage adjusting the output current of the solar panel catching always the maximum power from it. In this way it’s difficult charge the battery using the constant current/constant voltage method because i can’t control the charge current and i haven’t enough power from the solar panel.
In conclusion the charging of the battery is done with a small and variable charge current. Is that a problem? Can i charge the battery always in slow charge fase and with a variable current? If yes, which are the drawbacks?
Thank you. regards!
Andrea
On May 26, 2011 at 4:22am
Roy wrote:
Excellent!!! Love the detail…!
On May 26, 2011 at 6:54pm
edy wrote:
why lithium can perform fast charging between range 20% to 80% SOC only?
Why after 80% SOC charging became slow?
On June 12, 2011 at 4:27am
Joseph wrote:
My son and I have the same cell phone. His battery charge lasts 1 days and mine only one day. I came here to find out why. We thought it was because I was charging too frequently. I now believe its because I always left the phone on while charging whereas he turns his off. Thanks for the info!
On June 12, 2011 at 4:29am
Joseph wrote:
oops! 5 days vs 1 day…
On June 14, 2011 at 11:53pm
Nolan wrote:
Great article, thanks for the writeup.
One question: Would charging a Lithium battery with a higher amperage charger (but same voltage) cause any damage to the battery? I’m looking at +300mA to +500mA increase.
On June 15, 2011 at 9:53pm
Craig wrote:
Hello,
I have a cell phone with a lithium battery. Is it true that it is better to let the battery almost completely die before charging? I was told the battery has a memory. Someone also told me that was only true with NiCd.
On June 20, 2011 at 8:03am
Terry Bleasdale wrote:
nteresting article but it seems to be contradicted by information here:
http://www.electricbikehub.co.nz/?p=919
which states that Lithium Polymer can be left on charge between bike rides without detriment.
Which is correct please?
On July 4, 2011 at 6:34am
determan wrote:
Hello, my protected 18650 cell faced a high current draw and the protection circuit went to sleep mode.. the cell now measures just 0V!.. Do anyone know how can I wake up such a cell?.. Your help will highly be appreciated.. thanks..
On July 26, 2011 at 4:31am
Javier wrote:
Hey, very good article.
1. Where it says “The battery is continuously being discharged to 4.20V/cell and then charged by the device” I think you mean “The battery is continuously being CHARGED to 4.20V/cell and then DISCHARGED by the device”
2.¿Its ok to charge to a safe level, say 80% (thus preventing minicycles and overcharging the battery) with the device on?
3.¿How can you tell if the charger and/or the device has taken measures to prevent minicycles,overcharges,etc..?
On July 26, 2011 at 2:30pm
Ümit wrote:
Very vey thaks. Usefull informations.
On July 28, 2011 at 3:38am
Amkul wrote:
Hi everyone
I just wanna ask some of the experts here, whether it’s is OK for me to charge a lithium-ion battery (let’s say a 2Ah), with a constant current of 50mA and a float voltage of 4.1V?
Despite the slow charging rate (longer time of course), would this work and would there be any other problems?
On August 10, 2011 at 6:50am
JC22 wrote:
So, let me just make sure i have this straight.
I am building a charger and here is my what i am doing:
1. When battery is first connected charge at c/5 (as recommended by battery manu)
2. While in this stage continually read the voltage i am charging at to produce this current. (Question here: is this correct? or do i need to shut off my charge voltage and wait about a second for voltage to settle to battery voltage then read?)
3. When the voltage i am CHARGING at hits 4.2 at this current i charge at a constant 4.2 volts from this point on until the current drops below c/100 (as recommended by battery manu), or the total charge time exceeds 10hrs (as recommended by manu).
4. When my current hits this low i simply cut out the charge. Question - should i float the charge line at some value after charge?
So, basically i just want to make sure my method is basically correct. Am i reading the correct voltage to determine when to stop fast charging and when i am fully charged should i just leave the charge line at high impedence or should i float it to some value?
On August 12, 2011 at 2:28pm
jin wrote:
again, huge amount of misleading info here doesn’t mean everything is wrong. The author actually read these comments, but doesn’t reply to them, as he has deleted my previous post regarding the reliability of the info presented in this page.
On August 12, 2011 at 2:36pm
jin wrote:
To JC22:
2, you don’t need to cut off your charging voltage to see the stage of your battery.
3, no true; you are risking over-charging the battery at c/100 and more than 10 hours.
4, you shouldn’t float charge a lithium battery
5, When you are fully charged which shouldn’t be, you are not a battery. you should just stop risking over-charging yourself.
On August 12, 2011 at 2:40pm
jin wrote:
To Amkul:
You can charge with low current, but you shouldn’t float charge it. float charge means keep charging without stop; you have cut the charging current when this current is lower than 50ma; or you risk over-charge your battery.
On August 12, 2011 at 2:44pm
jin wrote:
to Javier:
1, yes, you are right.
2, It is totally fine.
3, there is no way you can tell; other than taking apart the charger and reconstruct the circuitry yourself.
On August 12, 2011 at 2:46pm
jin wrote:
To determan:
If your battery doesn’t charge up in the charger, the circuit probably is damaged.
On August 12, 2011 at 2:49pm
jin wrote:
To Craig:
You can charge lithium any time; memory effect is for the very old nicd only.
On August 12, 2011 at 2:52pm
jin wrote:
To Nolan:
You can, but never charge with more than 1C; and that is if you have a 1800mah battery; you shouldn’t charge it with 1.8A (1800ma);
On August 12, 2011 at 2:53pm
jin wrote:
Joseph:
It is not true; If you use your cell more than your son; then obviously it will last shorter.
On August 12, 2011 at 2:58pm
jin wrote:
I am afraid that you can’t charge a 7.5V battery with only 6v solar panel. You need 8.35V, so you need a dc to dc booster with regulation,but charging the battery with variable current is fine.
On August 12, 2011 at 3:04pm
jin wrote:
To skip:
It depends on the charger; but if the output voltage of those 2 charges is more than 12.3 Volt, both are not safe to charge your 10.8v battery.
On August 12, 2011 at 3:07pm
jin wrote:
To Ryan:
Your battery is your buffer. no cap is needed.
On August 12, 2011 at 3:09pm
jin wrote:
To zz:
You will over-charge the battery. It will expose eventually.
zz wrote:
what happens if you let a li-ion battery connected indefinitely at 4.0V?
On August 12, 2011 at 3:18pm
jin wrote:
TO MICHEL KUN:
As I know, PSP uses 5 volts power source. This either means that there is an internal circuit in the battery that boost the voltage from 4.2 to 5+ volts; or the battery is not made out of lithium. Either case, your battery should be safe to use.
On August 12, 2011 at 3:21pm
jin wrote:
To Jayk:
Depends on your needed voltage and power; higher voltage means higher voltage and higher power stored.
Jayk wrote:
I am unable to decide which is better - to select a Li-ion battery pack with multiple cells or single cell. For example, how to choose between a 3.7V, 1500mAhr and a 7.4V, 1500mAhr ?
On August 26, 2011 at 4:19am
Garry D wrote:
An enterpreneor claiming, new technology can charge Lithium Ion Battery can charge eight times more life ????
Comments Please ???
On August 26, 2011 at 2:23pm
zz wrote:
you mean explode… interesting, I figured current must be 0 once voltages equalise, so no overcharge
On August 28, 2011 at 3:39am
jin wrote:
To zz:
we are not in a perfect world. The charging voltage maybe more than 4.20, which means there is current going into the battery, and explode it eventually. On the other hand, due to the age of the cell itself, it may not has its maximun capacity voltage of 4.2. Normally when you charge the cell to 4.2 volt, it will drop a little bit. If a 4.2 volt charging current is kept charging that battery, eventually heats and pressure will built up and explode the battery.
On August 28, 2011 at 3:42am
jin wrote:
To Garry D,
Yes. technically, it is possible.
On September 8, 2011 at 6:23pm
ray wrote:
if i have a 3.7volts li-ion battery what is the output specification of my battery charger?
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Learn About Batteries
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Battery Testing and Monitoring
Difficulties with Testing Batteries How to Measure Internal Resistance How to Measure CCA (Cold Cranking Amp) How to Measure State-of-charge How to Measure Capacity Testing Lead Acid Batteries Testing Nickel-based Batteries Testing Lithium-based Batteries How to Monitor a Battery Battery Testing Equipment
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Cadex C5100 Battery Testing System
* A portable device should be turned off while charging. This allows the battery to reach the threshold voltage unhindered and reflects the correct saturation current responsible to terminate the charge. A parasitic load confuses the charger.
* Charge at a moderate temperature. Do not charge below freezing.
* Lithium-ion does not need to be fully charged; a partial charge is better.
* Chargers use different methods for “ready” indication. The light signal may not always indicate a full charge.
* Discontinue using charger and/or battery if the battery gets excessively warm.
* Before prolonged storage, apply some charge to bring the pack to about half charge.
* Over-discharged batteries can be “boosted” to life again. Discard pack if the voltage does not rise to a normal level within a minute while on boost.
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Comments
On November 10, 2010 at 3:39am
Adley wrote:
Super post there! Comprehensive and well collated material. Thanks for sharing.
On November 11, 2010 at 7:41am
Grosser wrote:
Very usefull information here, good thing I fond this page first before designing a charger for my custom-made battery pack.
P.S. You’re alwais talking about a 4,2V like they are the the standardwhat about 3,6V cells?
On November 12, 2010 at 3:52pm
Jason wrote:
Facinating stuff, although I doubt I will ever have the ambition to put it use.
On November 21, 2010 at 6:45am
Mike wrote:
Grosser,
3.6 is the nominal delivery voltage of a Li-ion cell, while 4.2 is the max charging voltage. They are the same battery. It’s the same situation with other battery chemistries, e.g. for a 12V lead-acid battery, you’d be charging to ~14V
On November 21, 2010 at 7:22pm
Paul Smith wrote:
My Li-ion battery is used in a Canon 50D DSLR camera; The charger blinks to indicate the level of charge. The indications are 1-blink series, 2-blink series, 3-blink series, and steady-on to indicate full charge. Often I leave the battery in the charger and go to bed if the LED is at the 2-blink state. When I wake up 4 to 5 hours later, the LED may have been steady-on for 4 hours. I have two questions. (1)What harm am I doing to my battery by following this practice and (2)Is the battery fully-charged if I remove it from the charger as soon as the steady-on state is reached?
On November 22, 2010 at 8:15am
Eduardo wrote:
I need to do the following test:
1 Question;
Have my charge Battery is Full. How time (day) can battery disconnect?
and
2 Questions
What time need battery recharge for has charge Full ?.
PD: My power Supply is 3,7 volt
On November 23, 2010 at 6:26pm
MANAS R. PANIGRAHI wrote:
what is the work of that circuit inside a lithium ion battery?
On November 24, 2010 at 7:29am
Eduardo wrote:
Thak You, unanswer.
The Batery is connected circuit 3,6 volt constant (regulable according to load) and this support a circuit for memory and a processor primary.
Thanks again.
Eduardo
On December 2, 2010 at 1:12am
Steve Webert wrote:
Does it benefit a lithium-ion or lithium-ion-polymer battery to periodically discharge it “fully” (ie, down to the above mentioned 2.7V-3.0V range)?
I have read several OEM’s offering differing strategies for optimizing battery life.
Thank you for your time and efforts—I very much appreciate the above instruction.
On December 9, 2010 at 2:02pm
Thomas Vargas wrote:
What about chargin vehicle batteries? This will be a big issue if they ever become popular.
How would the graph look if it were for vehicles?
On December 17, 2010 at 8:43pm
thomas micciantuono wrote:
Can lithium polymer cell phone batteries be over charged if left on charge to long and if left on to long will it diminish battery life.
On December 27, 2010 at 9:27pm
Andy wrote:
I’ve inherited an electric vehicle powered by two 38V/90Ah lithium-ion batteries. The voltage of both packs read around 9V only! The engine management system reports that a mere 21 hours of operation have been logged thus far. Are these battery packs truly dead-DEAD or is it possible to resuscitate them again in one way or another? Please advise. Cheers.
On January 3, 2011 at 10:21pm
Flynn Siy wrote:
I am looking for alternative charges for my HTC Desire. The standard charger that came with it is 5V and 1000mah. Since the charger uses a standard micro USB tip, there are a lot of available chargers out there with different Amp rating. Is it advisable to get a low Amp rating such as 500mah, higher amp such as 1200mah or stick with the same 1000amp? Is slow charging better than fast charging?
On January 6, 2011 at 12:50am
Jerry Conrad wrote:
My HTC EVO cellphone shuts down when the discharge voltage reaches 3.6 volts. Isn’t this reducing the use-capacity of this battery quite a bit?
On January 6, 2011 at 9:59pm
Jovy Macaspac wrote:
I’ve read somewhere that a charger with a lower voltage rating (e.g., 3.2v) cannot recharge a lithium battery with a higher voltage rating (e.g., 3.7v). Is this true? Something to do with electron transfer, I think… If this is true, I’m confused. How can a 3.7v charger charge a 3.2v battery to 4.2v if, when they reach the same voltage level (3.7v), it can no longer push said electrons around the battery?
Another question, if it’s alright: USB chargers have a rating of 5v. Would this cause problems with lithium batteries since as stated above, charging above 4.3v causes plating of the metallic lithium on the anode?
Thanks and more power!
Jovy
On January 7, 2011 at 6:47pm
Mr. D wrote:
how can you trickle charge a 12v batt @ 2v trickle and get a full charge . the battery is like a tank, with a limitation of it"s rateing ie. 4.2v or 12v ,is the limit that the battery will hold, forceing anything over that will start to burn the core of the battery in one way or the other ... do i win a cuppie doll??
On January 9, 2011 at 1:44pm
Vass wrote:
@ Flynn Siy, the ratings of the charger mentioned misguiding me as the standard charger rating should be in terms of volts and Amps/milli amps(mA) but not in mAh. If your concern is about a charger(i’ll interpret it to 500mA/12mA ) then go for 1200mA. There’s no harm in it. If you go for 500mA, it’ll charge but it become hot due to it’s inability to supply the rating current(say 1000mA).This inturn drop the voltage. If your concern is about a battery(a standard battery rating will be in volts and mAh), go for either one but in reduction in back up, in case if you chose 500mAh.Hope it cleared your doubt.
Cheers,
Vass.
On January 12, 2011 at 7:03am
Shiwakoti wrote:
How Li-ion battery gets recharged? Why at elevated temperature the battery life gets shortened? Does frequent charging pratice without being fully discharged affect bttery life span? Plz help..
On January 15, 2011 at 3:55am
Ike wrote:
“My HTC EVO cellphone shuts down when the discharge voltage reaches 3.6 volts. Isn’t this reducing the use-capacity of this battery quite a bit?”
—This is to protect the battery: further discharge could destabilize it and next charging could be risky (you may have heard of exploding LiIon batteries…).
Despite more strict cutoff liit, LiIons can store more energy than previous technologies iin same cell size, so you should not consider this a design fault/drawback, just a essential characteristic feature of this different chemistry.
—
Shiwakoti, you will find answers to your questions on the articles at this site: esp. in “Is lithium-ion the ideal battery?”. Shortly said, elevated temperature speeds up battery aging (it’s a chemical reaction a bit like how iron rusts faster in humid climate compared to dry circumstances) and it’s MUCH better to recharge often than let LiIons drain fully.
On January 15, 2011 at 5:43am
Shiwakoti wrote:
Thanks for the answer..
On January 23, 2011 at 1:08am
STEYAERT.DANIEL wrote:
GOED UITGELEGDE TEKST
On January 23, 2011 at 1:31pm
Curt Eglin wrote:
Excellent material. I now know how to properly charge a 3.7 volt Li-Ion pack I took out of a Blackberry phone that is since defunct. Tnx.
On February 2, 2011 at 2:24pm
Mike wrote:
So in this article is states that Lithium Ion batterys are charged upto 4.2v, where each cell can handle 4.2v +/- .05v. So the upperbound here is 4.25v to 4.15v. So, if you have a charger that is push the cells to 4.21v or 4.22v, then it is theoretically fine.
“A continuous trickle charge above 4.05V/cell would causes plating of metallic lithium that could lead to instabilities and compromise safety. “
Here though you say that raising the cell above just over 4v may cause plating. So by specification, charging lithium ion cells to 4.2v will cause plaiting?
On February 4, 2011 at 6:54am
captainirmak wrote:
i observe (via an application) that my smartphone is reaching till 4191 volts during re-charging the battery by usb cable.
can we say that battery is died a bit? cos it is not reaching 4.2 or above.
i know that it is very small numbers but curious about it.
and also what shold i do max charge the battery?
On February 4, 2011 at 2:21pm
Ken wrote:
The article mentions how dangerous it is to attempt charging cells that have been @<1.5v for just a few days. Well, that has not been in agreement with my experience. I occasionally salvage discarded Li-ion laptop battery packs…disassembling them to harvest the 18650’s for personal r/c and flashlight use. I commonly pull cells that are totally flat: 0v, sometimes even with polarity reversed by a few millivolts. In addition, some of the battery packs I ripped into were prehistoric by lithium chemistry standards (10 years+). More often than not all cells would recharge to their FULL original rated capacity and perform as new. I always test each cell individually with my iMAX B6 charger, manually putting them through at least a couple 500mA to 1Amp discharge/charge cycles. I have *never* experienced any safety nor reliability issues to date.
I would also like to brag of having had success restoring substantial capacity to the occasional cells that truly were worn. I will never share my method_IT’S MINE !_do not ask. ...Additionally, that procedure IS potentially dangerous and requires mandatory attentive supervision.
I suppose I’ve been laughing all the way to the battery bank. I know, horrible joke!
On February 11, 2011 at 1:30pm
TAS wrote:
What i have believed is keeping my laptop plugged in all the time at my desk and using the battery power in case of power failure or so. We have very frequent power cut-downs for brief spans. I also use BatteryCare to notify me of recalibration.
AFAIK Li-ion does not have memory effect and they have PMS circuit built-in so don’t overcharge.
A vendor of notebooks recently opposed and recommended to cycle discharges and recharges regularly to keep the battery healthy and prolong its life.
What’s the bottom line?
On February 11, 2011 at 1:32pm
tas wrote:
What i have believed is keeping my laptop plugged in all the time at my desk and using the battery power in case of power failure or so does no harm to my battery pack. We have very frequent power cut-downs for brief spans. I also use BatteryCare to notify me of recalibration.
AFAIK Li-ion does not have memory effect and they have PMS circuit built-in so don’t overcharge.
A vendor of notebooks recently opposed and recommended to cycle discharges and recharges regularly to keep the battery healthy and prolong its life.
What’s the bottom line?
On February 15, 2011 at 10:28am
Steven Hess wrote:
I just bought a Bushnell GPS and it has a Li-Ion battery pack. The instructions said to charge the li-Ion batteries for four hours. But upon plugging the charger to the batteries the green light immediatley came on, indicating a fully charged pack. But the pack is not charged at all. The unit will not turn on with these batteries. So my question is; Why is the charger displaying a Green LED when in fact the batteries need charged. And is there something I can do to make it start charging because the charger doesn’t charge when displaying a green light.
On February 15, 2011 at 1:06pm
Dan wrote:
Mike, I have been thinking of doing some EV experiments using some old laptop cells. They flat and packaged in plastic bags. What do you think about using this type of cell?
On February 16, 2011 at 12:24pm
Edward wrote:
i got a new phone. and it says b4 i do anything, i need to charge it for a total of 12 hours for it 2 run right, and battery life, blah blah…. but my question is, simple and plain… do i need to really charge it for the full 12 hours? can i just charge it until it says 100% charged, which would be in a hour or two…. i’ve google’d my question, and i’ve read mixed answers… “yes you should” “no, you don’t have to, because its a lithium-ion” whoop this, and whoop that…..
i would jus like a simpe answer.. yes or no… and why?
Thanx yous
On February 16, 2011 at 11:49pm
Samer wrote:
hi, i would like to know about the first charge lithium baattery ?
should i live chargim for 24h ?
thanks
On February 18, 2011 at 2:43am
Betty wrote:
Thanks so much. All the new gadgets (laptops, cell phones, portable TV-DVD kits, etc) don’t specify anything about the Battery “rules’ like they used to in the day of NiCad and NiMH. This article is very VERY informative and helpful. NOW, i better start unplugging my laptop… thought i was ‘saving’ the battery by keeping it plugged in while using. I guess i probably shouldn’t be charging my cell phone overnight for 8+hours either?
On February 19, 2011 at 2:33am
Ken wrote:
Great article, very informative. Can anyone help me with the following:
I have a Gibson Robot Guitar, the manufacturer states that it runs on:
(2 x 14500) 2.4v 2100mAh lithium rechargeable battery system.
These batteries have been run down for some time now and do charge, the manufacturer cannot replace them.
How can the voltage be 2.4v when the minimum cell voltage for lithium batteries is 3.6v What should I buy to replace these?
On February 25, 2011 at 9:12pm
marwan saade wrote:
dear sir
i have a vemar jiano helmet with integrated bluetooth. by mitake i’ve charged it with a nicd charger so the batterie was distroyed and does not work anynore.
when i opened the divice i found a li ion battery 3.7v 800ma reference stilo b001011.
please i would like to know if there is a way to fix it or recharge it again
if not can i use a a 1cell lypo battery to replace it
On February 28, 2011 at 11:14pm
to make money forex trading wrote:
You made some respectable points there. I looked on the internet for the issue and located most individuals will associate with together with your website.
On March 1, 2011 at 9:19am
BJ McGeever wrote:
So should I do my best to keep the battery at 40%? For instance I’ve been letting it hover around 40% by continually plugging and unplugging it. Is that a good idea?
On March 3, 2011 at 6:08pm
EDWARD BRIDGEWATER wrote:
IS IT POSSIBLE TO CHARGE A PACK OF SIX 1.2 LI-ION BATTERIES WITH THE ORIGANAL
CHARGER THAT WAS BUILT FOR CHARGING A PACK OF 6 1.2 BATTERIES
THE BATTERY PACK IS FOR A SCREW/DRIVER DRILL
I WOULD BE VERY GRATFULL FOR ANY HELP
EDWARD.
On March 10, 2011 at 2:31pm
Isidor wrote:
This article has been updated as of March 10, 2011 with all new information. Enjoy!
On March 10, 2011 at 8:07pm
Robert wrote:
Nice work Isidor. Thank you.
On March 12, 2011 at 10:10am
Lee Kunkiw wrote:
Mar. 13, 2011
To : Robert
I am looking for a 24V bicycle dynamo.
Is it available ? Please help me if you possible.
Thank you.
kunkiw77@gmail.com
On March 15, 2011 at 11:47am
TAS wrote:
What i have believed is keeping my laptop plugged in all the time at my desk and using the battery power in case of power failure or so does no harm to my battery pack. We have very frequent power cut-downs for brief spans. I also use BatteryCare to notify me of recalibration.
AFAIK Li-ion does not have memory effect and they have PMS circuit built-in so don’t overcharge.
A vendor of notebooks recently opposed and recommended to cycle discharges and recharges regularly to keep the battery healthy and prolong its life.
What’s the bottom line?
On March 17, 2011 at 8:22am
Subbu wrote:
Hi,
I have a simple ARM7 gadget and I want to run it on the Li-ion batteries which are available cheap. Is there any singly IC chip solution which could
a. Charge the battery when connected to mains/ USB
b. Indicate the content of charge to ARM7 (ARM7 can query and stop working if there is no charge left to function properly)
With best regards,
Subbu.
On March 25, 2011 at 6:44pm
Francisco Bolivar wrote:
I have an elerctric bike with a 600w - 36v motor.
It uses a li-Ion battery.
Usually each time I use the bike its charge drops about 20% of the total battery charge.
WHAT IS BETTER DO DO:
1 - CHARGE THE BATTERY EACH TIME I USE THE BYKE (battery with 80% of charge)
2 - CHARGE THE BATTERY ONLY WHEN IT REACHS 60% OR 40% OF CHARGE
On March 27, 2011 at 3:02pm
JimQ wrote:
I would like to make a battery pack charger for 4 Li ion cells. Would it be detrimental to limiting the charger voltage to ..say..15 volts. This would be within the voltage limit for each cell if the distribution is even.. However, if a cell is shorted there wpuld be excessove voltage on the other cells in the series string. Would it be better to design the charger for 4.0 volt peak and charger the 4 cells in parallel?
On March 28, 2011 at 7:20am
Dominic Gill wrote:
Excellent article. Thanks.
On March 30, 2011 at 1:00pm
MICHEL KUN wrote:
to
kunkiw77@gmail.com
most dynamo give an AC ourput,
you could try to use a transformer to UP the voltaje
Michel Kun
On March 31, 2011 at 11:47am
Hemanth wrote:
How to remove the charging time li ion battery ? Is there any alternatives way ?
On April 10, 2011 at 12:22pm
Wayne Robey wrote:
Informative article but the voltage drop in stage 3 would indicate a cell in poor condition. A good cell will drop less.
My observation on using batteries after being badly discharged:
About 5 years ago I purchased 40 nearly unused 18X65 cells in 2 cell packs with protect circuit. They ware all discharged to cell voltages of .01 to 1.1 v. I charged them for 10 hrs at c/100 (Now I think c/10 would be OK) and 10% failed shorted. The remainder charged well at c/10 to 4.2 V. Letting them set 24 hrs, I looked at the voltage drop and classified the lowest 10% as weak. Then making a 12 V pack from the remainder I had 2 unused cells classified as good. I have had no failures though they have not been treated roughly. I checked the voltage on the unused cells today. Those marked weak are above 3.7V and those marked good are above 3.9V.
On April 11, 2011 at 4:33am
michael dalton wrote:
Hey guys,
Just want to get this clear in my head. When charging the battery up, I get a controller to put constant current into the battery, then when I sense 4.2v/cell, I get the controller to go into constant voltage (of 4.2) mode and the current will die away naturally till fully saturated?
Cheers
MD
On April 11, 2011 at 7:42pm
Wayne Robey wrote:
Michael, NO, the manufacturer recommends that when 4.2 v is reached, let the current fall to c/10 then turn it OFF. I think a constant voltage charge can be done but it takes a long time and must be done at a lower voltage. When the above charging is done and the battery sits 12 hours, measuring the voltage and setting the float voltage to that is safe and gives maximum capacity but that voltage goes down as the battery ages. A float voltage of 4.1 is reasonable to get best capacity but as the battery gets old, that MIGHT make it age faster. Using the 2 step process of charging at 4.2 v till the current reaches your chosen value (>= c/10) then dropping the voltage to a float value would be the way to quickly charge then float it.
On April 12, 2011 at 4:54am
michael dalton wrote:
Hey Wayne,
Thanks for the reply. So is the current we are measuring the battery current or the current from the charger.
MD
On April 12, 2011 at 5:13am
michael dalton wrote:
Hey sorry Wayne I think I’m becoming confused. Do you apply a constant voltage in stage 2 until the current reaches c/10 OR manually bring the current down to c/10 with a controller?
Cheers
MD
On April 12, 2011 at 5:55pm
Erik wrote:
Why can the the battery pack in a Tesla automobile be charged considerably faster when the charging unit is 240v vs. 110-120v?
I iam a complete novice, and am wondering if higher voltage input decreases charging time.
Thanks for any insight you can offer.
On April 13, 2011 at 5:55pm
Wayne Robey wrote:
Michael,
Not all Li cells are the same so the numbers I use below are for the most common ones, some can be charged much faster.
The algorithm is to check the voltage and if it is < ~3 charge at no more than c/10. If it is >3v charge with limits of c/2 and 4.2 volts until a current of c/10 is reached, then stop . As mentioned in the article a voltage < 4.2 increases battery cycle life, shelf life, and reduces discharge capacity for the current cycle. A charge rate < the maximum rated is easyer on the battery. I think charging with variable current is satisfactory if current is limited as specified on the data sheet and the voltage is limited to 4.1 volts. This is good for float charging and charging from a variable source.
Erick
There is no inherent reason. It was designed that way to account for commonly available power connections, commonly limited to 20A (use at < 80% of limit) at 120v but commonly available at 50 A or more at 240V.
On April 14, 2011 at 12:47am
Jayk wrote:
I am unable to decide which is better - to select a Li-ion battery pack with multiple cells or single cell. For example, how to choose between a 3.7V, 1500mAhr and a 7.4V, 1500mAhr ?
On April 18, 2011 at 9:41am
MICHEL KUN wrote:
i am
CONFUSED
got some PSP battery from HK
I measuered 4.8 volts on end of charge
4.5 volts after 3 days standing
THEN WHY IS 4.2VOLTS MAXIMUM in all litterature
is this value ABSOLETE???
the battery seem to work OK.
thanks in advance for any help or informations
On April 21, 2011 at 4:37am
Alex wrote:
Amazing website… well written .. very very useful
Great Job
On April 24, 2011 at 8:33pm
nash wrote:
Great article!!
On April 25, 2011 at 6:54am
zz wrote:
what happens if you let a li-ion battery connected indefinitely at 4.0V?
On May 3, 2011 at 2:36pm
Ryan wrote:
So I am building a solar powered usb charger for an android device. I know that my available curent and voltage at the time of charging will vary depending on the panel so in addition to overcharging I am wondering if capacitors to buffer power is necessary. I have also considered a 3000mAh battery with an integrated charging circuit would be better. That would offer me more consistent ouput to the device and be a contingency for a lack of or poor lighting. Any ideas would help. Kudos on the page, very informative.
On May 5, 2011 at 8:02am
Bilal nasir zargar wrote:
i brought a new battery sony lithium-ion NP-BG1, WHEN I BUY IT , IT WAS IN SLEEPING MOOD, i plugged the charger for charging, but it did not charge, so please suggest me what should i do…
On May 7, 2011 at 9:19pm
mike wrote:
Great article. Well written and very informative - just what i was looking for. Thanks and keep up the excellent work.
On May 8, 2011 at 8:35am
JimQ wrote:
Great informative article. For a “12volt” pack, I would charge 3 or for Li Ion cells with a constant current source and limit the volts per cell by connecting a 4.0 volt zener diode across each cell. This would allow parallel charging but also protect the cells from ‘over voltage’. Does this make sense? The total charging current would be limited by the charging source circuitry and shut off after all cells reached 4.0 volts.
On May 9, 2011 at 1:08pm
TONY wrote:
Li-Ion (Poli)bat
Min V=2.7V ? 3.0V
Midle=3.6-3.7 (Li-Ion Li-Pol)
end of Charging 4.2V Sel Kill 4.3V+
Kill it Fast 4.35 +
On May 9, 2011 at 1:41pm
MICHEL KUN wrote:
what about voltajes for
LiFePo4
thanks
On May 9, 2011 at 1:51pm
TONY wrote:
Higher charge voltages boost capacity but lower cycle life and compromise safety.
Li-ion battery to 4.20V/cell. This allows maximum runtime
We have limited information by how much lower charge voltages prolong battery life; this depends on many conditions, as we have learned. What we do know, however, is the capacities. At a charge to 4.10V/cell, the battery holds a capacity that is about 10 percent less than going all the way to 4.20V/cell. In terms of optimal longevity, a charge voltage limit of 3.92V/cell works best but the capacity would be low. Besides selecting the best-suited voltage thresholds, it is also important that the battery does not stay in the high-voltage stage for a long time and is allowed to drop after full charge has been reached.
V4.20 end of Charging 100 MA (Panasonic ?)
On May 9, 2011 at 2:04pm
TONY wrote:
4.20 400+ capacity 80%
4.25 400 bat capacity 25%
4.3v 250 Cycles 50%
4.35v 190 Cycles 25%
On May 12, 2011 at 4:07pm
Skip wrote:
My laptop has a battery rated at 10.8V, 85Wh, 8800mAh. The charger outputs 18.5V, 3.5A, and 65W. I have an old charger that is rated 19V, 3.4A and 65W. Would it be safe to use the old one?
On May 13, 2011 at 1:38am
Andrea wrote:
Hi,
i want to charge a 7.5 v 400 mAh li-ion battery from a small solar panel (6V - 1W).
I would connect the solar panel and the battery with a voltage regulator or with a MPP circuit that fixed the output voltage adjusting the output current of the solar panel catching always the maximum power from it. In this way it’s difficult charge the battery using the constant current/constant voltage method because i can’t control the charge current and i haven’t enough power from the solar panel.
In conclusion the charging of the battery is done with a small and variable charge current. Is that a problem? Can i charge the battery always in slow charge fase and with a variable current? If yes, which are the drawbacks?
Thank you. regards!
Andrea
On May 26, 2011 at 4:22am
Roy wrote:
Excellent!!! Love the detail…!
On May 26, 2011 at 6:54pm
edy wrote:
why lithium can perform fast charging between range 20% to 80% SOC only?
Why after 80% SOC charging became slow?
On June 12, 2011 at 4:27am
Joseph wrote:
My son and I have the same cell phone. His battery charge lasts 1 days and mine only one day. I came here to find out why. We thought it was because I was charging too frequently. I now believe its because I always left the phone on while charging whereas he turns his off. Thanks for the info!
On June 12, 2011 at 4:29am
Joseph wrote:
oops! 5 days vs 1 day…
On June 14, 2011 at 11:53pm
Nolan wrote:
Great article, thanks for the writeup.
One question: Would charging a Lithium battery with a higher amperage charger (but same voltage) cause any damage to the battery? I’m looking at +300mA to +500mA increase.
On June 15, 2011 at 9:53pm
Craig wrote:
Hello,
I have a cell phone with a lithium battery. Is it true that it is better to let the battery almost completely die before charging? I was told the battery has a memory. Someone also told me that was only true with NiCd.
On June 20, 2011 at 8:03am
Terry Bleasdale wrote:
nteresting article but it seems to be contradicted by information here:
http://www.electricbikehub.co.nz/?p=919
which states that Lithium Polymer can be left on charge between bike rides without detriment.
Which is correct please?
On July 4, 2011 at 6:34am
determan wrote:
Hello, my protected 18650 cell faced a high current draw and the protection circuit went to sleep mode.. the cell now measures just 0V!.. Do anyone know how can I wake up such a cell?.. Your help will highly be appreciated.. thanks..
On July 26, 2011 at 4:31am
Javier wrote:
Hey, very good article.
1. Where it says “The battery is continuously being discharged to 4.20V/cell and then charged by the device” I think you mean “The battery is continuously being CHARGED to 4.20V/cell and then DISCHARGED by the device”
2.¿Its ok to charge to a safe level, say 80% (thus preventing minicycles and overcharging the battery) with the device on?
3.¿How can you tell if the charger and/or the device has taken measures to prevent minicycles,overcharges,etc..?
On July 26, 2011 at 2:30pm
Ümit wrote:
Very vey thaks. Usefull informations.
On July 28, 2011 at 3:38am
Amkul wrote:
Hi everyone
I just wanna ask some of the experts here, whether it’s is OK for me to charge a lithium-ion battery (let’s say a 2Ah), with a constant current of 50mA and a float voltage of 4.1V?
Despite the slow charging rate (longer time of course), would this work and would there be any other problems?
On August 10, 2011 at 6:50am
JC22 wrote:
So, let me just make sure i have this straight.
I am building a charger and here is my what i am doing:
1. When battery is first connected charge at c/5 (as recommended by battery manu)
2. While in this stage continually read the voltage i am charging at to produce this current. (Question here: is this correct? or do i need to shut off my charge voltage and wait about a second for voltage to settle to battery voltage then read?)
3. When the voltage i am CHARGING at hits 4.2 at this current i charge at a constant 4.2 volts from this point on until the current drops below c/100 (as recommended by battery manu), or the total charge time exceeds 10hrs (as recommended by manu).
4. When my current hits this low i simply cut out the charge. Question - should i float the charge line at some value after charge?
So, basically i just want to make sure my method is basically correct. Am i reading the correct voltage to determine when to stop fast charging and when i am fully charged should i just leave the charge line at high impedence or should i float it to some value?
On August 12, 2011 at 2:28pm
jin wrote:
again, huge amount of misleading info here doesn’t mean everything is wrong. The author actually read these comments, but doesn’t reply to them, as he has deleted my previous post regarding the reliability of the info presented in this page.
On August 12, 2011 at 2:36pm
jin wrote:
To JC22:
2, you don’t need to cut off your charging voltage to see the stage of your battery.
3, no true; you are risking over-charging the battery at c/100 and more than 10 hours.
4, you shouldn’t float charge a lithium battery
5, When you are fully charged which shouldn’t be, you are not a battery. you should just stop risking over-charging yourself.
On August 12, 2011 at 2:40pm
jin wrote:
To Amkul:
You can charge with low current, but you shouldn’t float charge it. float charge means keep charging without stop; you have cut the charging current when this current is lower than 50ma; or you risk over-charge your battery.
On August 12, 2011 at 2:44pm
jin wrote:
to Javier:
1, yes, you are right.
2, It is totally fine.
3, there is no way you can tell; other than taking apart the charger and reconstruct the circuitry yourself.
On August 12, 2011 at 2:46pm
jin wrote:
To determan:
If your battery doesn’t charge up in the charger, the circuit probably is damaged.
On August 12, 2011 at 2:49pm
jin wrote:
To Craig:
You can charge lithium any time; memory effect is for the very old nicd only.
On August 12, 2011 at 2:52pm
jin wrote:
To Nolan:
You can, but never charge with more than 1C; and that is if you have a 1800mah battery; you shouldn’t charge it with 1.8A (1800ma);
On August 12, 2011 at 2:53pm
jin wrote:
Joseph:
It is not true; If you use your cell more than your son; then obviously it will last shorter.
On August 12, 2011 at 2:58pm
jin wrote:
I am afraid that you can’t charge a 7.5V battery with only 6v solar panel. You need 8.35V, so you need a dc to dc booster with regulation,but charging the battery with variable current is fine.
On August 12, 2011 at 3:04pm
jin wrote:
To skip:
It depends on the charger; but if the output voltage of those 2 charges is more than 12.3 Volt, both are not safe to charge your 10.8v battery.
On August 12, 2011 at 3:07pm
jin wrote:
To Ryan:
Your battery is your buffer. no cap is needed.
On August 12, 2011 at 3:09pm
jin wrote:
To zz:
You will over-charge the battery. It will expose eventually.
zz wrote:
what happens if you let a li-ion battery connected indefinitely at 4.0V?
On August 12, 2011 at 3:18pm
jin wrote:
TO MICHEL KUN:
As I know, PSP uses 5 volts power source. This either means that there is an internal circuit in the battery that boost the voltage from 4.2 to 5+ volts; or the battery is not made out of lithium. Either case, your battery should be safe to use.
On August 12, 2011 at 3:21pm
jin wrote:
To Jayk:
Depends on your needed voltage and power; higher voltage means higher voltage and higher power stored.
Jayk wrote:
I am unable to decide which is better - to select a Li-ion battery pack with multiple cells or single cell. For example, how to choose between a 3.7V, 1500mAhr and a 7.4V, 1500mAhr ?
On August 26, 2011 at 4:19am
Garry D wrote:
An enterpreneor claiming, new technology can charge Lithium Ion Battery can charge eight times more life ????
Comments Please ???
On August 26, 2011 at 2:23pm
zz wrote:
you mean explode… interesting, I figured current must be 0 once voltages equalise, so no overcharge
On August 28, 2011 at 3:39am
jin wrote:
To zz:
we are not in a perfect world. The charging voltage maybe more than 4.20, which means there is current going into the battery, and explode it eventually. On the other hand, due to the age of the cell itself, it may not has its maximun capacity voltage of 4.2. Normally when you charge the cell to 4.2 volt, it will drop a little bit. If a 4.2 volt charging current is kept charging that battery, eventually heats and pressure will built up and explode the battery.
On August 28, 2011 at 3:42am
jin wrote:
To Garry D,
Yes. technically, it is possible.
On September 8, 2011 at 6:23pm
ray wrote:
if i have a 3.7volts li-ion battery what is the output specification of my battery charger?
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