panasonic NCR18650A charge current

bestsystem · Oct 21, 2011

I have purchased a xtar WP2 II charger for charging my panasonic 3100mahs

I am charging two of them simultaneously, and wonder which charge current (500ma or 1000ma, switch position 1 or 2)should I choose?

NCR18650A's datasheet says the maxium charge current is 0.3C=930ma only?

RI Chevy · Oct 21, 2011

I think you could use the 1000 maH setting for the 3100's.

45/70 · Oct 21, 2011

Hi best. I'm with RI, I think you could get away with the 1000mA rate, as it's so close. Going "by the book" though, the 500mA rate should be used. The lower rate will likely extend cell life and also actually charge the cell to a bit higher capacity, as well, so the 500mA rate has that going for it.

Dave

bestsystem · Oct 24, 2011

I use 500 ma if i have time

and at 500ma, the charger tends to be cooler

LEDAdd1ct · Jan 10, 2012

Thank you for this thread!

I just saw this post here, and now I am concerned. I was going to charge this cell at 1.2 amps.

1) Is this dangerous?

2) Will this damage the cell?

It is suprising to me that a cell with such a [relatively] high capacity has such a low charge rate!

If this damages the cell in the sense of "instead of getting 500 cycles, you will only get 350 cycles," then I can live with that. If it damages the cell in the sense "vent with technicolor flame and then burn down the house," well, that is a different story altogether.

moderator007 · Jan 10, 2012

Well reading the Callie's Kustoms site info. It says for the charge rate 885mah standard and 3100mah max. Redilast at iluminationsupply says max charge current 3.1A and recommended charge current of .3C. Redilast homepage says charge at <1C of battery capacity. AW says 885ma recommended charge rate and no maximum charge rate at lighthound. Couldn't get in to the marketplace to check his sales thread. Eagletac doesn't list a charge rate but in their discharge graph they list the battery in the test, charged at 885ma.

hellokitty[hk] · Jan 11, 2012

IMO charging at 3A is fine.
Using a 1/10 cutoff will also undercharge the cell and increase longevity.

Heavytrevy · Jan 11, 2012

I charge my 3100 ncr's at 3.5 amps and they dont get hot.
Reduced batt life dosent bother me, but but waiting hours for chargin just kills me.

LEDAdd1ct · Jan 11, 2012

With Panasonic putting out releases (can't find the post now) stating 3.4 and even 4.0 amp hour cells are being worked on, I could care less if I don't get the maximum amount of cycles out of the cell. They will be obsolete before then.

The million dollar question is this:

"What negative effects, if any, will one experience when they deviate from Pansonic's published maximum charge rate?"

The various dealers can state what they like, but they do so in direct contradiction to Panasonic's own specs. Here is a link to the PDF in question:

Link

For those without a PDF reader handy, it states:

"CHARGE CONDITION: CVCC 4.2V Max.0.3It(885mA), 60mA cut-off at 25deg.C"

Again, the question is not whether or not charging above 885mA is outside spec, as it clearly is.

The question is what, if any, deleterious effect on the cell it will have, and whether that effect will result in:

1) Shortened cell lifetime
2) Risk of fire/explosion
3) Reduced capacity

4) All of the above

and,

At how much current above spec are you putting yourself and your loved ones at risk.

Perhaps if we are fortunate SilverFox will pop by for a visit...

EDIT: After reading this post again, I realize I may sound alarmist. However, these are lithium ion cells, and they do need to be treated with care. If the various dealers have a different publication and/or have direct information from Panasonic stating that it is okay to charge up to 1C, then that is a different story. It just makes me anxious when the spec sheet states specifically that the "MAX" charge rate is 0.3C.

moderator007 · Jan 11, 2012

LEDAdd1ct said:
With Panasonic putting out releases (can't find the post now) stating 3.4 and even 4.0 amp hour cells are being worked on, I could care less if I don't get the maximum amount of cycles out of the cell. They will be obsolete before then.

The million dollar question is this:

"What negative effects, if any, will one experience when they deviate from Pansonic's published maximum charge rate?"

The various dealers can state what they like, but they do so in direct contradiction to Panasonic's own specs. Here is a link to the PDF in question:

Link

For those without a PDF reader handy, it states:

"CHARGE CONDITION: CVCC 4.2V Max.0.3It(885mA), 60mA cut-off at 25deg.C"

Again, the question is not whether or not charging above 885mA is outside spec, as it clearly is.

The question is what, if any, deleterious effect on the cell it will have, and whether that effect will result in:

1) Shortened cell lifetime
2) Risk of fire/explosion
3) Reduced capacity

4) All of the above

and,

At how much current above spec are you putting yourself and your loved ones at risk.

Perhaps if we are fortunate SilverFox will pop by for a visit...

EDIT: After reading this post again, I realize I may sound alarmist. However, these are lithium ion cells, and they do need to be treated with care. If the various dealers have a different publication and/or have direct information from Panasonic stating that it is okay to charge up to 1C, then that is a different story. It just makes me anxious when the spec sheet states specifically that the "MAX" charge rate is 0.3C.

Its like ever thing else LEDAdd1ct, only time will tell. Maybe in a year or so will start getting reports of things happening to these cells that are being charged at to high of a current. They may start building a high internal resistance and loosing capacity. But we want know until someone has put a few hundred cycles on their cells charging at 1C or higher. Time will tell.

And I agree better to follow panasonics recommended charge current. They made and tested the battery well beyond what any of us has yet. They should know whats best for the cell and safety.

milkyspit · Jan 12, 2012

Folks, another CPFer directed me to this thread, hoping for some guidance. I'm hardly the last word on Li-ion cells! I defer to somebody like SilverFox for that sort of stuff.

That said, my traditional rule of thumb on recharging Li-ion chemistry (based on conversations with SilverFox?) has been 0.5C maximum charge rate. I could be mistaken, but traditionally that was a good rule of thumb, and somewhat of an industry standard.

HOWEVER, the Panasonic data sheet (another CPFer supplied a link in an above post) specifically dictates a maximum charge rate of 0.3C and even then, it's based on the data sheet's specified guaranteed minimum capacity of 2950mAh. That means you should charge these cells using a charge current of no higher than 885mA.

Now, it just so happens that the Pila IBC charges cells at roughly 800mA, so that would seem a perfect match. (These figures, again, from memory, so please confirm on your own equipment!)

I'll also offer that if you're ever in doubt, stick around while you're charging your 18650 cells, and every once in a while gently touch the cells with your finger: if the casing feels more than lukewarm, TERMINATE THE CHARGE IMMEDIATELY, then let the cells cool and try again later at a lower charge rate. Heat is a sign that something's not right. Put another way: Li-ion chemistry should never get hot when charging! Better safe than sorry.

Hope this helps. Be safe everyone! Better to charge a little more slowly than to risk a disastrous event.

jtr1962 · Jan 14, 2012

I concur here with Scott. Remember that these cells have a higher capacity. As such there are probably changes which were made to the chemistry which dictate the charging rate Panasonic recommended. Remember that going by the 0.5C guideline charging currents will continually increase with new developments which increase cell capacity. This obviously can't happen because there are absolute physical limits on how fast you can charge any cell based on internal resistance or other factors. Imagine a hypothetical 20000 mAh 18650 sometime in the future. 0.5C charging would mean 10 amps. Obviously charging at that high a current will present problems on multiple levels. Therefore, as cell capacity continues to rise, charging rates expressed in terms of C will undoubtedly fall.

In practical terms, the time difference charging at 885 mA versus 1200 mA will not be directly proportional to the current differences. If you charge at a lower rate, the time spent in the constant voltage portion of the charge curve will decrease. This will partially offset the longer time spent in the constant current charging mode.

LEDAdd1ct · Jan 14, 2012

Thanks, guys!

orbital · Jan 20, 2012

Charging profile

LEDAdd1ct said:
......
EDIT: After reading this post again, I realize I may sound alarmist. However, these are lithium ion cells, and they do need to be treated with care. If the various dealers have a different publication and/or have direct information from Panasonic stating that it is okay to charge up to 1C, then that is a different story. It just makes me anxious when the spec sheet states specifically that the "MAX" charge rate is 0.3C.

+

In our litigious world,, underrated limits are so common that one becomes numb to what products can truly do.
...Max Load of this or Max pressure of that, ect..ect..

Even if Panasonic states 885ma for charge,, bumping that to 1000ma does not concern me in the least.

Charging profile is also a factor.

/>/>/>

CKOD · Jan 20, 2012

orbital said:
Charging profile

+

In our litigious world,, underrated limits are so common that one becomes numb to what products can truly do.
...Max Load of this or Max pressure of that, ect..ect..

Even if Panasonic states 885ma for charge,, bumping that to 1000ma does not concern me in the least.

Charging profile is also a factor.

/>/>/>

It is most likely for cell life. If they promise a minimum of x cycles, you have to follow the specs in the datasheet if you expect to get the promised minimum. If you operate outside of the specified parameters, then all bets are off. If youre cells arent heating up durching charging then you arent going to experience a run away thermal reaction, but if its outside the charge spec, then you could be impacting cycle life.

orbital · Jan 20, 2012

^

12% increase in charging current = no concern for me

~ side note: the max drive listed for XR-E & XP-E is 1A,
..how many lights High or Turbo mode go waaaayy past that? {almost all}

bshanahan14rulz · Mar 27, 2012

Everybody's been looking at the datasheet where it doesn't exactly specify a charge current or discharge current.

Check this document instead: https://industrial.panasonic.com/www-data/pdf/ACI4000/ACI4000PE5.pdf
note the NNP series states charge at 0.3C max, charge at 0.1C if cell is 2.9V or less
the NNP series states discharge at 1C max, so 2.9 or 3.1A depending on your model, down to 2.5V.

HKJ · Mar 27, 2012

bshanahan14rulz said:
Everybody's been looking at the datasheet where it doesn't exactly specify a charge current or discharge current.

Check this document instead: https://industrial.panasonic.com/www-data/pdf/ACI4000/ACI4000PE5.pdf
note the NNP series states charge at 0.3C max, charge at 0.1C if cell is 2.9V or less
the NNP series states discharge at 1C max, so 2.9 or 3.1A depending on your model, down to 2.5V.

Panasonic has many different datasheet. I have one for the NCR18650A cell that specify standard charge 590mA, quick charger 1475mA, termination current 60mA and never go above 4.25 volt, even with puls charging.

roadkill1109 · Mar 28, 2012

I wish there was a battery conditioner for Lithium Ion cells like the one for NiMH cells. That would drain the battery to its lowest limit, then charge it. I've noticed that properly drained batteries when charged last longer than cells that you charge from time to time even when it still has a lot of juice left.

Kokopelli · Apr 1, 2012

I guess keeping them full all the time would kill them faster than charging them just a few hundreds of mA higher. I always discharge my cells to %40 if I plan to keep them idle for longer than a week. A fully charged cell looses its %15 capacity in a year while a %40 charged cell only looses its %4 capacity, in the same storage temperatures, arround 25-30'C. And cells better kept cooler, at 10-20'C, then these losses drop even lower.

panasonic NCR18650A charge current

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