NCM vs lifepo4?

emaayan

emaayan

100 kW
Joined
May 10, 2012
Messages
1,450
Location
israel
hi...

i was recently told that NCM batteries are infact 4 year old technology and are being attempted to re-sold as a better technology then lifepo even though they are more dangerous.
 
I moved your topic from ebike technical to battery technology, where it is more appropriate.


Also, you might want to try reading up on the various threads discussing such batteries; you might find a lot more information than a single person's opinion. ;)
 
What's NCM anyway? So many chemistires nowdays. Another lithium polymer type? Or a different kind of nicad?
 
I expect he's talking about the Li-Ni-Co-Mn, also called NMC, like the Zero uses, or the EIG cells Jay64 has and JonesCG was talking about getting direct from EIG. I think the Leaf also uses them, cells by LG.

There are also a number of ebike packs made from them now, htough I strongly suspect those arent' nearly teh same quality/type as the Zero / EIG or Leaf / LG cells.
 
Ahh. Thank you. I got confused by the lack of an L at the start of the acronym.

I need to look up all this stuff too, and write up a cheat sheet card to keep nearby. Like my mph to kph chart. You got chemisty names, then the slang names based on manufacurers, etc.

I just barely have lifepo4, lico, nicad, lead straight in my brain.

Is NMC more dangerous than lifepo4? As dangerous as lico? In between? I don't recall any zero fireballs.
 
Liveforphysics has tested those and many other batteries, with probably pretty severe abuse, to find out which ones would be best for the Zero. I'm pretty sure he's posted about those tests and stuff, if you search thru his posts.
 
ice_robin said:
NMC may means Li-Ni-Co-Mn, but I still thinks lifepo4 is better, it is more stable.
Click to expand...


In GM's 50Million dollar cell testing program for the Chev Volt batteries, LG Chem's NMC cells won out over A123 LiFePO4 cells because of the increased safety and stability of NMC.


Like any type of cell chemistry, there are total garbage NMC cells and there are extremely high quality NMC cells.
 
trying to electrify my ride & pick the best, longest lasting, lightest & safest 36V battery pack for a 36v 250w geared hub. I've searched the web & come down to Panasonic Li(NiCoMn)O2 LITHIUM ION CGR18650CH vs Ping Battery LiFePO4. It seems LiFePO4 is safe, however, panasonic makes a lighter NCM battery pack, which the seller claims is newer, better performer & safer than LiFePO4. Ping battery claims LiFePO4 is safest w/ 2000x recharges & has tons of positive feedback to back it up w/ customers who've had battery packs for 6+ years. I'm torn between the 2 battery packs. Where can I get more info? Here is the panasonic cell in question:
 

Attachments

  • cgr18650ch_data_sheet.pdf
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You can see in your panasonic cells specs the cells goes from 2200mAH to 1900mAH capacity under 300 cycles. So it looses 14% of its capacity quite quickly. Following this graph, at 1000 cycles it should go under 60% capacity.

So it seems for long term pack, lifepo4 is better value for money?
 
liveforphysics said:
ice_robin said:
NMC may means Li-Ni-Co-Mn, but I still thinks lifepo4 is better, it is more stable.
Click to expand...


In GM's 50Million dollar cell testing program for the Chev Volt batteries, LG Chem's NMC cells won out over A123 LiFePO4 cells because of the increased safety and stability of NMC.
Click to expand...

I what ways are they safer or more stable? And why would GM use A123 cells for the Spark if the Volt's cells are superior? I heard a different story about why A123 wasn't in the Volt, and while I can't say for sure if it's true, it's very plausible in the context visible from my perspective.
 
 
http://em3ev.com/store/index.php?route=product/product&path=35&product_id=123

The above link is a shameless, deliberate lie. In their own words:
Our 14S 9P, 50V 18.5Ah Samsung SDI Battery Pack uses the SDI ICR18650-22P 4.5C rated cell.
Click to expand...

Samsung ICR18650-22P is NOT NMC. ICR = Lithium (I) Cobalt (C) Rechargeable (R). Real life test have shown that this cell can barely tolerate 5A (2.27C) continuous discharge, let alone 9.9A (4.5C) as claimed by the seller.

Discharge curves at 2,3, & 5A ...
http://www.dampfakkus.de/akkutest.php?id=73
Click to expand...

Worse, this misrepresentation is repeated over and over and perpetuated by members of this forum.

For true NMC 18650 cell from Samsung, look for Samsung INR18650-xxy. Note the difference, "N" instead of "C". I have tested the Samsung INR cells and they can sustain 3C comfortably. xxy is the capacity designation.
 
wb9k said:
liveforphysics said:
ice_robin said:
NMC may means Li-Ni-Co-Mn, but I still thinks lifepo4 is better, it is more stable.
Click to expand...


In GM's 50Million dollar cell testing program for the Chev Volt batteries, LG Chem's NMC cells won out over A123 LiFePO4 cells because of the increased safety and stability of NMC.
Click to expand...

I what ways are they safer or more stable? And why would GM use A123 cells for the Spark if the Volt's cells are superior? I heard a different story about why A123 wasn't in the Volt, and while I can't say for sure if it's true, it's very plausible in the context visible from my perspective.
Click to expand...

LFP has been putting out misinformation about batteries ever since I have been reading this forum.

He is for sure the worst guru on our forum.

He bragged up using hk lipo for a long time and when I was a newbee I bought some.

Worst batteries I ever bought and wasted money.

I should have never read any of his posts.

He is bad for the ebike movement. A total joker that does not help people understand but confuses people.
 
Lifepo4 A123 and cellman's or lester's NCM packs ? Lifepo4 is heavier but more cycles and power. What's it for ? Go make cradboard box of the size of each battery. Write down the motor package to see if you get a strong enough battery for your needs. Is this a fun bike or a bike that's going inside the office building or train ? The kids as that means you need to daddy over it.
 
I've been using HK lipo going on 3 years now without a failed pack. At this time, I wouldn't use anything other than RC lipo. The 10ah 88.8v hk lipo pack I've got over 4000 miles on now cost under $300. I expect it to last another year or two and another 4000-8000 miles.
 
LFP has been putting out misinformation about batteries ever since I have been reading this forum.

He is for sure the worst guru on our forum.

He bragged up using hk lipo for a long time and when I was a newbee I bought some.

Worst batteries I ever bought and wasted money.

I should have never read any of his posts.

He is bad for the ebike movement. A total joker that does not help people understand but confuses people.
Click to expand...



Maybe you should inform Zero motorcycles of your opinion. He is their battery expert. He also did the same thing for Microsoft.

I am interested in your qualifications as a battery expert. But until you can prove that you know more that LFP, I suggest that you keep your mouth shut. You really do come off as a total idiot.

I look at you as just another opinionated fool with not much experience.

Ever heard of the "signal to noise ratio"? Your posts are the noise part.

Have a nice day :D
 
etriker, I am sorry to hear of your expensive exercise with LiPo. I do not recommend LiPo to newbies, but I have recommended it to racers who have displayed an understanding of the risks involved.

In order to help others avoid your unfortunate experience, could you please share what type of HK LiPo it was? (20C, Nano-tech, Zippy, Turnigy, etc), and would you please also list your charger type, LiPo protections (LVC, low voltage buzzer, Methods LiPo protection kit, etc). Did you charge to 4.2V, 4.1V, etc...(side note: is your charger for sale?)

Any info you would be willing to share may help someone else avoid a similar fate.
 
nicobie said:
LFP has been putting out misinformation about batteries ever since I have been reading this forum.

He is for sure the worst guru on our forum.

He bragged up using hk lipo for a long time and when I was a newbee I bought some.

Worst batteries I ever bought and wasted money.

I should have never read any of his posts.

He is bad for the ebike movement. A total joker that does not help people understand but confuses people.
Click to expand...



Maybe you should inform Zero motorcycles of your opinion. He is their battery expert. He also did the same thing for Microsoft.

I am interested in your qualifications as a battery expert. But until you can prove that you know more that LFP, I suggest that you keep your mouth shut. You really do come off as a total idiot.

I look at you as just another opinionated fool with not much experience.

Ever heard of the "signal to noise ratio"? Your posts are the noise part.

Have a nice day :D
Click to expand...

Yeah, I know. Just makes it all the worse.

I don't see him trying to get us those great cells unless we buy a Zero ? How can we check out his claims ?

Microsoft, Ouch. Won't let you inside either.
 
SamTexas said:
http://em3ev.com/store/index.php?route=product/product&path=35&product_id=123

The above link is a shameless, deliberate lie. In their own words:
Our 14S 9P, 50V 18.5Ah Samsung SDI Battery Pack uses the SDI ICR18650-22P 4.5C rated cell.
Click to expand...

Samsung ICR18650-22P is NOT NMC. ICR = Lithium (I) Cobalt (C) Rechargeable (R). Real life test have shown that this cell can barely tolerate 5A (2.27C) continuous discharge, let alone 9.9A (4.5C) as claimed by the seller.
Click to expand...

Above statement seems a bit strong, and perhaps factually inaccurate.
On SamsungSDI's own site (and they should know), they state that several of their ICR18650 cells are NCM chemistry.
See: http://www.samsungsdi.com/battery/cylindrical-rechargeable-battery.jsp

My own real-world experience with EM3ev and with their Samsung battery packs:
- EM3ev dealt straight with me, did not push one chemistry over another, was very candid in providing advice about the operating profiles of each (energy density, probable life span, best practices for charging, etc). I opted for the Samsungs over A123 for reasons of weight / energy density.
- I've run one of their Samsung batteries (48V, 12.6Ah) for ~500 miles. It has performed solidly at 30A draw... very common, as I live in hilly area. I've tried it at up to 40A, but only for short tests as did not want to damage MAC gears... but it seemed very able to deliver 40A during tests.

I'm not a battery expert, and can't say whether the pack will withstand the test of time, but so far I'm happy.
 
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