Samsung INR18650-25R cycle test.

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Re: Samsung INR18650-25R cycle test.

Post by Hillhater » Nov 04 2015 8:44am

TheBeastie wrote:This is why I am a fan of a overly parallel-yfied P build pack, you get more total cycles (and less sag) compared to a thinner P setup that torture your cells to early death.
It certainly will give a much longer useful battery life,...but the trade off is obviously extra weight.
Effectively , you are admitting the cells do not have the energy density/cycle life you need !
I would like to see a comparison graph for a 20amp discharge using a 3.1v cut off ?.....just to know for certain what effect pushing down into that 2.5 v level has.
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Re: Samsung INR18650-25R cycle test.

Post by DrkAngel » Nov 04 2015 11:21am

I thought I had already mapped the Samsung INR18650-25R.
Copied results over from my Capacity Mapping (Optimal Charge-Discharge Voltages) thread.

DrkAngel wrote:Image

Using graph I built a discharge map.
(Based on .2A <.1C discharge rate line)
Scaled in Wh rather than my typical mAh ... sorry.

In "Paint" I "enlarged", added .05V lines, "scaled" 1/10th increments to 0 to 1, copied and pasted and dragged to carefully measure discharge line intersections with various voltage increments.

2.80 = .04
2.85 = .04
2.90 = .04
2.95 = .05
3.00 = .07
3.05 = .07
3.10 = .08
3.15 = .08
3.20 = .07
3.25 = .07
3.30 = <.1
3.35 = .1
3.40 =.1
3.45 = .45
3.50 = .4
3.55 = .4
3.60 = .7
3.65 = .85
3.70 = .6
3.75 = .55
3.80 = .35
3.85 = .5
3.90 = .5
3.95 = .6
4.00 = .35
4.05 = .4
4.10 = 1.0
4.15 = .3
4.20 = <.1wh

Bar graph would be more accurate, actual capacity would be a horizontal line to the lower .05V.


Image

Shows good capacity from 3.40V till initial sag below 4.20V.
Displays similar hills and valleys to various other of my "mapped" LiPo.

IN|R18650-25 Capacity Bar Graph from .2A discharge graph

Image

Between 3.40V and 4.10V appears optimal for best usable capacity with least "wear and tear" ... IMO ...
Capacity map point from 4.20V to 4.15V would be higher than "mapped", due to the "natural" voltage sag from static to discharge voltage.
The 4.10V - 4.15V, at this very low discharge rate, should be reasonably accurate.
The massive bulge of capacity from 4.05V - 4.10V is very common, typical of many Lipo cells I've mapped and should be considered accurate.
This indicates ≥4.10V as optimal charge point, the OPs 4.15V looks to be reasonably optimal!
Based on the OPs 1C discharge, compared to the multiple discharge rate graph, I would advise 3.30V as the optimal 1C discharge point for maximum capacity vs life!
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Re: Samsung INR18650-25R cycle test.

Post by electricbike » Nov 04 2015 12:22pm

Uppdated 160 cycles.

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Re: Samsung INR18650-25R cycle test.

Post by parabellum » Nov 04 2015 3:18pm

electricbike wrote:Uppdated 160 cycles.
Looks broken, can not open now.

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Re: Samsung INR18650-25R cycle test.

Post by electricbike » Nov 04 2015 3:44pm

parabellum wrote:
electricbike wrote:Uppdated 160 cycles.
Looks broken, can not open now.
I have fixed it now i think.

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Re: Samsung INR18650-25R cycle test.

Post by Hillhater » Nov 04 2015 4:51pm

DrkAngel wrote:I thought I had already mapped the Samsung INR18650-25R.
Copied results over from my [url=https://endless-sphere.com/forums/viewtopic........
Sorry DrkAngel, ...I was meaning the capacity loss /cycle life graph at 20 amps but cutting at 3.1volts instead of 2.5v
It's just not clear if it's the discharge rate, charge rate, or DOD voltage that kills the capacity with these repeated cycling ?
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Re: Samsung INR18650-25R cycle test.

Post by DrkAngel » Nov 04 2015 6:27pm

All other factors being equal...
discharge-charge rates are a major factor in capacity degradation.

E.G. C rate is a major and progressive factor in battery deterioration!

Image
Deterioration to 80% of original capacity:
3C produces < 50 cycles
2C produces ~ 250 cycles
1C produces ~ 500 cycles
High C rate discharges (and charges) are progressively damaging and as actual capacity declines, deterioration accelerates rapidly!
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Re: Samsung INR18650-25R cycle test.

Post by Hillhater » Nov 04 2015 8:02pm

Interesting info DA..
What cell/ chemistry was that for ?
But It's always irritating when the test changes more than one variable at a time ( charge and discharge !)
I guess I need to get a few cells and start testing ! :wink:
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Re: Samsung INR18650-25R cycle test.

Post by circuit » Nov 05 2015 2:18am

DrkAngel wrote:All other factors being equal...
discharge-charge rates are a major factor in capacity degradation.

E.G. C rate is a major and progressive factor in battery deterioration!

Image
Deterioration to 80% of original capacity:
3C produces < 50 cycles
2C produces ~ 250 cycles
1C produces ~ 500 cycles
High C rate discharges (and charges) are progressively damaging and as actual capacity declines, deterioration accelerates rapidly!
Hard to tell when there are no temperature graphs. Possibly it also correlates with higher temperature at higher rates.
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Re: Samsung INR18650-25R cycle test.

Post by electricbike » Nov 05 2015 6:53pm

FIrst post uppdated 180 cycles.

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Re: Samsung INR18650-25R cycle test.

Post by DrkAngel » Nov 05 2015 7:49pm

Updated and enhanced ...
Attachments
Cycle Life vs Capacity.jpg
Cycle Life vs Capacity.jpg (90.05 KiB) Viewed 1861 times
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Re: Samsung INR18650-25R cycle test.

Post by DrkAngel » Nov 05 2015 11:03pm

Pimped out the present info ...
Attachments
Cycle Life vs Capacity.jpg
Cycle Life vs Capacity.jpg (113.16 KiB) Viewed 1845 times
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Re: Samsung INR18650-25R cycle test.

Post by h0tr0d » Nov 06 2015 9:51am

DrkAngel wrote:Optimal discharge depth looks to be 3.30V at a 1C discharge rate.
This likely relates to a ~3.40V static voltage (After discharge removed)

Image
EDIT:
80ºC @ 3C 6 C discharge? HOT!
Last edited by h0tr0d on Nov 06 2015 10:41am, edited 1 time in total.
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Re: Samsung INR18650-25R cycle test.

Post by DrkAngel » Nov 06 2015 10:27am

INR18650 - 25R, according to graph, hit 80ºC at a 15A (6C) discharge rate.
20A discharge (8C) I graphed OPs test against, hits near 100ºC - (Yes, you can cook on the battery pack)

Let me post up the INR18650 - 25R 20A discharge cycle life graph from Samsung:

Image

While battery is 20A capable, for multiple (obvious?) reasons, I would not recommend it for more than brief moments!
Attachments
INR18650 - 25R (20A).jpg
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Last edited by DrkAngel on Nov 08 2015 9:48am, edited 1 time in total.
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Re: Samsung INR18650-25R cycle test.

Post by electricbike » Nov 07 2015 11:51am

Uppdated 200 cycles.

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Re: Samsung INR18650-25R cycle test.

Post by DrkAngel » Nov 08 2015 11:37am

Updated multi-graph and added feasible projected capacity lines through 500 cycles.

Image
Attachments
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Re: Samsung INR18650-25R cycle test.

Post by electricbike » Nov 09 2015 6:37am

I think i will buy 2 more of those Reaktor chargers so i can do 3 testing with 3 different parameters at the same time.

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Re: Samsung INR18650-25R cycle test.

Post by electricbike » Nov 10 2015 6:23am

What parameters do you want me to change in my next INR18650-25 test?
I think i will do a 2C discharge.

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Re: Samsung INR18650-25R cycle test.

Post by h0tr0d » Nov 10 2015 7:00am

electricbike wrote:What parameters do you want me to change in my next INR18650-25 test?
I think i will do a 2C discharge.
To simulate aggressive riding and regen, can you do this?
-Discharge 4C 10s
-Charge 2C 10s
Measure temperature all the way.
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Re: Samsung INR18650-25R cycle test.

Post by DrkAngel » Nov 10 2015 9:59am

h0tr0d wrote:
electricbike wrote:What parameters do you want me to change in my next INR18650-25 test?
I think i will do a 2C discharge.
To simulate aggressive riding and regen, can you do this?
-Discharge 4C 10s
-Charge 2C 10s
Measure temperature all the way.
100A discharge likely exceeds capabilities.
Single cell at 4C continuous discharge = 60ºC (140ºF) accumulated temperature (unknown if occasional 2C charge will reduce or increase thermal path?)
Building a combined pack is liable to greatly amplify temperature.
Active cooling is highly recommended to avoid damage and danger! (Bonus of better efficiency and extended life?)
Last edited by DrkAngel on Nov 10 2015 10:10am, edited 1 time in total.
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Samsung INR18650-25R cycle test recommendations.

Post by DrkAngel » Nov 10 2015 10:00am

Due to the noticeable disparity between your test capacity and that of the manufacturer ...
I would like to see a few capacity control-comparison tests,
4.20V >>> 2.50V @ 2.5A (Similar to OEM test voltage)
4.20V >>> 3.10V @ 2.5A (Your test voltage +OEM high)
4.15V >>> 3.10V @ 2.5A (Your test voltage, as control)
4.15V >>> 2.50V @ 2.5A (Your test voltage + OEM low)
4.10V >>> 3.30V @ 2.5A (My derived optimal 1C C\D rate)

Run each test singly on each of 5 cells (5 cell x 5 tests = 25 single tests total)
  • This should help determine:
  • additional capacity at each voltage area
  • If capacity difference is due to:
    discharge device
    individual cell
    voltage range
For a full test ...
I would like to see a full run of my derived optimal C\D voltage for 2.5A (1C) of ...
4.10V >> 3.30V @ 2.5A

Your 4.15V to 3.1V @ 2.5A (1C) displays excellent life preservation-extension ... but more is better!
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Re: Samsung INR18650-25R cycle test.

Post by electricbike » Nov 10 2015 12:01pm

h0tr0d wrote:
electricbike wrote:What parameters do you want me to change in my next INR18650-25 test?
I think i will do a 2C discharge.
To simulate aggressive riding and regen, can you do this?
-Discharge 4C 10s
-Charge 2C 10s
Measure temperature all the way.
In cycle mode the Reaktor can only charge/discharge at the same current and minimum wait time is 1 min so
no, can't do that sorry.

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Re: Samsung INR18650-25R cycle test recommendations.

Post by electricbike » Nov 10 2015 12:05pm

DrkAngel wrote:Due to the noticeable disparity between your test capacity and that of the manufacturer ...
I would like to see a few capacity control-comparison tests,
4.20V >>> 2.50V @ 2.5A (Similar to OEM test voltage)
4.20V >>> 3.10V @ 2.5A (Your test voltage +OEM high)
4.15V >>> 3.10V @ 2.5A (Your test voltage, as control)
4.15V >>> 2.50V @ 2.5A (Your test voltage + OEM low)
4.10V >>> 3.30V @ 2.5A (My derived optimal 1C C\D rate)

Run each test singly on each of 5 cells (5 cell x 5 tests = 25 single tests total)
  • This should help determine:
  • additional capacity at each voltage area
  • If capacity difference is due to:
    discharge device
    individual cell
    voltage range
For a full test ...
I would like to see a full run of my derived optimal C\D voltage for 2.5A (1C) of ...
4.10V >> 3.30V @ 2.5A

Your 4.15V to 3.1V @ 2.5A (1C) displays excellent life preservation-extension ... but more is better!
Ok, i will start those test when i get my ordered reaktors, maybe a couple of days.

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Re: Samsung INR18650-25R cycle test.

Post by h0tr0d » Nov 10 2015 12:31pm

electricbike wrote:
h0tr0d wrote:
electricbike wrote:What parameters do you want me to change in my next INR18650-25 test?
I think i will do a 2C discharge.
To simulate aggressive riding and regen, can you do this?
-Discharge 4C 10s
-Charge 2C 10s
Measure temperature all the way.
In cycle mode the Reaktor can only charge/discharge at the same current and minimum wait time is 1 min so
no, can't do that sorry.
Ok then,
2C charge/discharge, 4.1V - 3.3V?
Thank you Justin! Life is so much sweeter with this forum... ;)

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Re: Samsung INR18650-25R cycle test.

Post by electricbike » Nov 10 2015 12:46pm

h0tr0d wrote: Ok then,
2C charge/discharge, 4.1V - 3.3V?

Sure, no problem, i will do that when the chargers arrive.
Edit: Actually Samsungs spec say no more than 4A in rapid charge.

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