I was looking for cycle life info on the Samsung 30Q. Samsung datasheets only quote the cycle life for 15A discharge, which is ~78% at ~300 cycles. 15A is pretty high, but they don’t have info for more modest discharge rates.
A user there has done testing at 7A and got ~77% at 500 cycles.
There’s also some interesting info on charge rate in that thread. It shows how high capacity cells like the GA really shouldn’t be charged at more than 0.5C.
Just thought this would be of interest here since the 30Q is one of our favorites.
General discussion of the charge rate is at the top of page 2. Then there is some cycle life testing of high capacity cells at different charge rates near the top of page 6.
As the .5C observation is think is valid but consider that
.5 x 3,450 is still a 1.725 amp charge rate, pretty fast in my opinion, (Standard charging current: 1.475 A)
The Panasonic-Sanyo GA is a good high-capacity cell when you need up to 10 amps of maximum continuous discharge current. It has a high energy density - 693 Wh/l volumetric and 224 Wh/kg gravimetric. This is a popular choice for electric vehicles.
Battery specifications:
Model: NCR18650GA
Manufacturer: Panasonic-Sanyo
Country of Origin: Japan
Chemistry: NCR
Max. continuous discharge current: 10A
Typical capacity: 3450 mAh
Minimum capacity: 3350 mAh
Nominal voltage: 3.6 V
Charging voltage: 4.20
Standard charging current: 1.475 A
Well your trend is fine, but I would encourage everyone to just look at the manufacture data sheet for your particular cell. It is really the least we can do to responsibly use these tools.
I think the recommended charge current for the GA is 1.5 or 1.6A, and damage seems to be sensitive to the charge current so I would stay on the safe side.
I would never post info about batteries that is in any way safety hazard.
It is all about safety.
NCR18650GA can be charged at CC higher than 2 Amps, but of course I do not recommend it. As long as temp is within 10°C to +45°C range you are good. To be on the safe side I would say 10°C to +40°C max.
LG Hg2 , He2, He4, Hd2, Hd2C, Hb6, Hb4 - Samsung 30Q , 25R, 20R - Sony VTC4, VTC5, VTC5A, VTC6 = max charge current 4 Amp <<<< All confirmed
It is more a matter of premature capacity degradation. As discussed in the link above, if the charge rate is too high, particularly at high states of charge, Li ions will form Li metal instead of intercalating in the carbon as it is meant to. This is one cause of capacity degradation.
Charging is not a huge problem when it comes to degradation.
Chargers that we all use are less than 1 Amp (a few of them can go up to 2 Amps), and that is good thing.
What will lead to premature capacity degradation is discharging the cell at max load current.
To give you one example:
LG HG2 - very popular (with good reason) 3000mAh cell cycle life:
300 cycles at 10Amp load
and
200 cycles at 20Amp load
Source with datasheet here:
For LG MJ1 official max charging current is 3.4A , but I said 2A just for safety reasons (for our new forum members).
NCR18650GA is 3.35A, but my max recommended charging current is 2A
Well as long as the charge rate is not too high it is not a problem. Testing done on p6 in the above link shows degradation does occur with too fast charge rates.
Significant or not - degradation will always be there.
It is li-ion battery, and you cannot save it from degradation.
I’ve just posted what degradation difference is btwn 10 Amp and 20 Amp load.
Same with Samsung 30Q ( 4 Amp max charging current).
Discharging is what really kills them, or should I say high temperature.
This is not a contest between whether charging or discharging causes more damage.
Also, I don’t think you looked at the tests in the link I posted; we are talking capacity degradation to ~65% within 100 cycles when charging at 1C. I was not aware of the extent to which some cells are damaged with this level of fast charging, which is why I’m sharing it.
Surely the point is to get as many cycles out of cell as possible? Thus if the the specs for GA state “Standard charging current: 1.475A”, then we should be recommending to not charge at much more than 1.475A.
I also clearly said 2 Amps max. for GA and MJ1 (manuf. absolute max is 3.35A and 3.4A)
Guy who performed tests did a lot of work, but he did not care about manuf datasheets.
The charging temperature should be confined to the range 10°C to +45°C (this is the most important part for successful charging w/o damages to the cell)
Keep it below 38-40°C and you are good to go.
Charging at 1C is absolute max charging current that cell can handle.
Repeatedly charging at 1C will kill that cell of course.
The same goes for max discharge rate. Yes, it can handle 10-11Amps but how many cycles?
There is significant drop in capacity after 150 cycles at 6 Amp load. Now imagine how many cycles will be at 10-11 Amp load.
I would not even comment on Samsung INR18650-35E, because Samsung could do a better job, but it did not.
Perhaps some here use hobby chargers at high charge rates but I would venture the vast majority use commonly available chargers sold with the cells, which for the most part have a 1A charge rate or less. So the charging issue is a very low percentage possibility while the discharge issue is very real.
Using 18350’s in triples and in MT-G2 direct drive style lights the capacity losses show up pretty quick, the little guys take a hit delivering 10 or more amps.
Wear and tear, a fact of life, from our cars to our own bodies it’s just the way things are. Run the heck out of the cells then recycle em and get the latest and greatest, repeat til satisfied.
Some might call it wasteful, then they hop in their SUV that guzzles expensive gasoline and race off like there was no tomorrow…. seriously, do you see people driving like gas mileage was critical? I sure don’t! Point being we buy the cells to use, using them is what makes us happy in this hobby, and using them VERY hard is what puts the schoolgirl giggles on our faces, like driving the car too fast or stopping late. Sure it’s wasteful, but isn’t that part of what makes it fun?
Makes me want to fire up my Quad Ti X6 at 21A on a single cell…. WoooHoooo! Ever seen a Noctigon Meteor pulling 33.7A? :smiling_imp:
I’ve only seen one data sheet for the GA cell, linked on in this page:
The standard charge is 1.475A, and it mentions charging at 1.675A. So I’m curious where you have seen the manufacture suggest the max charge rate is 3.35A.