Samsung 30Q INR18650-30Q 3000mah 15a cell

Ok, the mfr sent me a build with fixed cycle testing,
I set one up to start with:
3A charge to 3.65V (taper to 2A)
2A charge to 3.9V (taper to 1.2A)
1.2A charge to 4.15V with 200mA cut.
7A discharge to 2.75V (~21 minutes, very heavy load)

repeat for 450 cycles.

should be good for ~14 cycles per day...

I used the stepped charging to fast charge the cell without damaging it. Gleaned from Tesla. CC/CV charging is bad for Lithium Ion in general... plan to start a thread bout that in the future.

Will also setup a similar cycle test on a Model S cell. Need to calibrate the other 7 channels first.
 
okashira said:
I used the stepped charging to fast charge the cell without damaging it. Gleaned from Tesla. CC/CV charging is bad for Lithium Ion in general... plan to start a thread bout that in the future.

Need more info, now.
 
okashira said:
CC/CV charging is bad for Lithium Ion in general... plan to start a thread bout that in the future.

Bad ? Are you kidding ? It's proved that it's the best way to charge a Lithium battery faster and increasing the number of charging cycle.
 
Teh Stork said:
okashira said:
I used the stepped charging to fast charge the cell without damaging it. Gleaned from Tesla. CC/CV charging is bad for Lithium Ion in general... plan to start a thread bout that in the future.

Need more info, now.

CC/CV is only used because that's what we had available. CC/CV power supplies existed even before we had lithium ion batteries.
CC/CV is fine, but you need to set the CC current super low to match the worse case part of the charge, ie, the current at the highest voltage.

fast charging damages lithium ion cells because, at higher states of charge, when there is more lithium in the anode, high currents will lead to enough of a lithium concentration gradient across the anode that it can lead to lithium coming out of solution and plating the surface of the anode, or forming lithium dendrites, which is generally irreversible.
The solution for CC/CV is to set you CC current for the highest the cell can take at 4.2V. But this leads to a charge that takes the typical 4-5 hours. In reality, you can use much higher currents at low SOC, because there is less lithium concentration in the anode, thus diffusion occurs more quickly.

Thus the ideal charge curve for a lithium ion battery is highest current at low SOC, tapering as the anode becomes more and more saturated with lithium.
 
Punx0r said:
What's the rationale behind the 4.15V terminal voltage?

I want to do a ~90% DOD. Should have used ~4.13 and 2.65V, But close enough for now.
 
okashira said:
fast charging damages lithium ion cells because, at higher states of charge, when there is more lithium in the anode, high currents will lead to enough of a lithium concentration gradient across the anode that it can lead to lithium coming out of solution and plating the surface of the anode, or forming lithium dendrites, which is generally irreversible.
The solution for CC/CV is to set you CC current for the highest the cell can take at 4.2V. But this leads to a charge that takes the typical 4-5 hours. In reality, you can use much higher currents at low SOC, because there is less lithium concentration in the anode, thus diffusion occurs more quickly.
This makes sense as far as it goes, but what's going on at very low SOC? The usual technique to "rescue" an overdischarged cell is to trickle charge to some voltage, then proceed as normal. So you have minimal current below some threshold, but then it's fine to turn it up to 11 above the threshold. What happens in between?
 
cycborg said:
okashira said:
fast charging damages lithium ion cells because, at higher states of charge, when there is more lithium in the anode, high currents will lead to enough of a lithium concentration gradient across the anode that it can lead to lithium coming out of solution and plating the surface of the anode, or forming lithium dendrites, which is generally irreversible.
The solution for CC/CV is to set you CC current for the highest the cell can take at 4.2V. But this leads to a charge that takes the typical 4-5 hours. In reality, you can use much higher currents at low SOC, because there is less lithium concentration in the anode, thus diffusion occurs more quickly.
This makes sense as far as it goes, but what's going on at very low SOC? The usual technique to "rescue" an overdischarged cell is to trickle charge to some voltage, then proceed as normal. So you have minimal current below some threshold, but then it's fine to turn it up to 11 above the threshold. What happens in between?

My guess is that's more of a safety precaution then anything to do with rescuing the cell?
If the cell is significantly damaged dumping large current will cause it to go way high and lead to something worse on a cheap cell...
That or another effect related to cathode, separator, electrolyte, etc. Many of the happenings inside these cells are still not fully understood.
 
okashira said:
Teh Stork said:
okashira said:
I used the stepped charging to fast charge the cell without damaging it. Gleaned from Tesla. CC/CV charging is bad for Lithium Ion in general... plan to start a thread bout that in the future.

Need more info, now.

CC/CV is only used because that's what we had available. CC/CV power supplies existed even before we had lithium ion batteries.
CC/CV is fine, but you need to set the CC current super low to match the worse case part of the charge, ie, the current at the highest voltage.

fast charging damages lithium ion cells because, at higher states of charge, when there is more lithium in the anode, high currents will lead to enough of a lithium concentration gradient across the anode that it can lead to lithium coming out of solution and plating the surface of the anode, or forming lithium dendrites, which is generally irreversible.
The solution for CC/CV is to set you CC current for the highest the cell can take at 4.2V. But this leads to a charge that takes the typical 4-5 hours. In reality, you can use much higher currents at low SOC, because there is less lithium concentration in the anode, thus diffusion occurs more quickly.

Thus the ideal charge curve for a lithium ion battery is highest current at low SOC, tapering as the anode becomes more and more saturated with lithium.

Makes logical sense.

Q: So do you think a super low 0.1C charge would have the same benefit since it is a low current throughout the whole process rather than just at high SOC. I ask because I tend to charge my battery over a 8-10 hour period at 60W. (It's a 1500Wh battery that I use about 500Wh each trip and I only charge to 4.0 Vpc)
 
Makes logical sense.

Q: So do you think a super low 0.1C charge would have the same benefit since it is a low current throughout the whole process rather than just at high SOC. I ask because I tend to charge my battery over a 8-10 hour period at 60W. (It's a 1500Wh battery that I use about 500Wh each trip and I only charge to 4.0 Vpc)
Sure that's perfectly good. Just slow :-D

Going away from CC/CV enables one to charge faster with the same amount of wear. Or charge at the same speed with less wear.
If you don't care about charge time, then it doesn't matter. 0.1C is well below the rate where you're essentially getting no wear from the charge rate.

Also if you charge to less then 4.2V, you can use a higher CC. Because you never hit that higher SOC where the CC is still maxed out.

For example, if you charge to 4.2V with CC/CV, you might want to stick to 800mA per cell to be ultra safe on a high capacity cell (like a Model S cell)
If you charge to 4.1V, maybe 1.2A would be okay, since you're at a lower SOC when you transition to CV phase.
4.0V, perhaps 1.5-1.8A. There is a steep decline above 4V from what I have seen on Model S charging.

This 30Q probably has a nice porous anode, so they say you can CC/CV to 4A in fast charge mode, but that would sacrifice cycle life.
I wouldn't be surprised if you can do 8A at low SOC, taper to 4A, and go down to ~1.5A at the end and not add any wear and still charge faster then a 4A CC/CV.
Tesla uses 4A on Model S cells until ~35% SOC.
 
cycborg said:
alexis57 said:
It's proved
Please provide references.
For example: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6360973
"cc cv lithium" or "lithium charging" on IEEE website and you'll see all papers and conferences about the lithium charging. Most of them said CC CV is the fastest and best solution to get the full charge quickly by keeping the cycle life. Others said there are some best other algorithms for speed, or for cycle life, it's a trade-off between parameters.

Does it really matter ? Most of people on Endless-Sphere doesnt care at all, they just charge their battery pack with a power supply.
 
alexis57 said:
cycborg said:
alexis57 said:
It's proved
Please provide references.
For example: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6360973
"cc cv lithium" or "lithium charging" on IEEE website and you'll see all papers and conferences about the lithium charging. Most of them said CC CV is the fastest and best solution to get the full charge quickly by keeping the cycle life. Others said there are some best other algorithms for speed, or for cycle life, it's a trade-off between parameters.

Does it really matter ? Most of people on Endless-Sphere doesnt care at all, they just charge their battery pack with a power supply.

Obviously, people care. Since you don't, feel free to stop replying.
 
alexis57 said:
Most of people on Endless-Sphere doesnt care at all, they just charge their battery pack with a power supply.
Actually, I'd guess that most people on ES use either a Kingpan-style charger or an RC balance charger. I assume these are alexis57-approved methods?

People's interest in power supply charging or tapered charging indicates their interest in expanding their toolkit. Not sure how this could be confused for a lack of "caring". Your contempt for these methods is a reflection of the narrowness of your understanding.
 
Ou alors je suis tout simplement pas anglais et quand j'ai dit "don't care" ce n'était pas avec la bonne signification. Mais si tu n'es pas capable de faire la différence, alors ouvres-toi un peu plus l'esprit ;)

When someone say "I'll use a power supply for my battery pack", yes they totally don't care that the CC CV is not the best solution for charging LiPo.
I don't see the problem, there wasnt any unkind thought.
 
Peut-etre je ne suis pas capable, but I was interpreting your words in the context of things you have written previously. I'll take you at your word, though, regarding your intended meaning.

I think it's fair to say this is an enthusiasts' thread, even within the context of ES which is heavily populated with enthusiasts. We're talking about a cutting-edge cell and cutting-edge charging techniques. So even though it may not be relevant to a lot of users now, I can imagine that in a year or two someone will post 30Q packs for sale in the marketplace, and someone else will offer a charger that allows an 80% charge in 20 minutes, and they'll do a brisk business. These early steps of seeking out what's available and finding out what the limits are - this is how we move forward.
 
This is graph from manufacturer of nissan leaf cells, it proves what has been told:

img_graph_index02.gif


http://www.eco-aesc-lb.com/en/product/liion_ev/#anc01

So, basically one should use charge profile in which current is steadily decreasing?
 
Interesting. I have a Leaf, and I don't know exactly what the charging algorithm is, but it's definitely faster at low SOC (I use 6.6 kW level 2; my car doesn't have the DC quick charge option). It's nice how that works out, since low SOC is exactly when you want to push the charge in quickly to get the most range.

The Leaf also takes this into account for regen. There's a display that shows the available regen in 5 discrete levels, not sure what that corresponds to in physical units. At full charge you can't do regen at all, but then it's not like there's some threshold voltage where all of a sudden you have full regen. You gradually have more available as the SOC drops from 100% to 50-60%.
 
cycborg said:
Interesting. I have a Leaf, and I don't know exactly what the charging algorithm is, but it's definitely faster at low SOC (I use 6.6 kW level 2; my car doesn't have the DC quick charge option). It's nice how that works out, since low SOC is exactly when you want to push the charge in quickly to get the most range.

The Leaf also takes this into account for regen. There's a display that shows the available regen in 5 discrete levels, not sure what that corresponds to in physical units. At full charge you can't do regen at all, but then it's not like there's some threshold voltage where all of a sudden you have full regen. You gradually have more available as the SOC drops from 100% to 50-60%.

Yes. Here is a fast charge curve for a Model S cell:

file.php


Note it goes to about 0.9A by the time it hits the CV phase at 4.2V.

So, if you're doing CC/CV charging to 4.2V, safe would be 0.9A. But supercharging allows you to use 4A, down to 2A up to 70% SOC.

I suspect the 30Q could take an epic fast charge. I'll setup an ultra fast charge routine and cycle test with it.. Ill use 6-7A at low SOC...

The 3A/2A/1A charge routing i'm currently running is already pretty damn fast. 1 hr 45 min average for 95% charge.
 
Here is the first 16 cycles.
Some glitches in the first few so I deleted those data-points.

Average columbic efficiency 0.99928 (99.928%)
Average round trip energy efficiency of 90.93%; very impressive for a quick charge and 7A discharge.
^^ The efficiency numbers should be extremely accurate since it's an average of 15 cycles and the same voltage sense and current sense equipment is used for the round trip.

I borrowed a Fluke 8808A from work to help calibrate the other 7 channels. Then ill get another regimen running on a 30Q and some Model S cells.

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That is one stable cell. Can we get them at a reasonable price yet?
otherDoc
 
I got this quote yesterday for 130 Cells


Hi Wayne,

Thank you for you inquiry!

Price for 130pcs Sasmung 18650 3000mah battery is USD3.68/pc, it is a high drain Samsung battery, have 15A discharge current.

In stock now, can make delivery immediately, may i know is it ship to Australia? May be i can give a shipping cost for your reference first.

Hope we can get a chance to serve you, looking forward to your reply!

Best Regards,

Aimee Lee


SIBEILE TECHNOLOGY

TEL: 86 755 84737145

WEB: http://www.sblbattery.com

SKYPE: ls724705881

Edit : direct link to battery .... http://www.sblbattery.com/product/60269621619-800733140/12v_18650_battery_pack_SIBEILE_SAMSUNG_30Q_3000mAh_15A_3_7V_Rechargeable_Battery_Cell_12v_18650_battery_pack.html
 
Updated

Average columbic efficiency 99.959%
Average energy efficiency 90.894%

I think this should answer the question - that lithium ion cells don't have any Peukert effect / Peukert #. Lead acid used at this kind of charge and discharge rate would be like 60% energy efficient! perhaps worse...
i.e., α = 0, k = 1
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Calibrated three more channels. I'll start a model S cell with a similar charge routine and 4A discharge.
Then i'm taking suggestions. ..
 
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