Battery Musing: What makes A123 batteries different?

[Mooch]

In preparation for posting the A123 26650 test results I wanted to briefly list how the lithium-ferrous-phosphate chemistry ("LFP") batteries from A123 Systems, Inc., differ from the batteries we normally use when vaping.

A123 batteries have several advantages:

• Their low internal resistance means they are able to supply more current before overheating and they hold their voltage up better.
• LFP is the safest of the Li-Ion chemistries. It has a higher threshold temperature for thermal runaway and less violent reactions if the battery does go into runaway.
• LFP offers long cycle life, i.e., it is capable of a larger number of charge/discharge cycles than the other Li-Ion chemistries.

A123 batteries have a few disadvantages though:

• The 26650 is only 2400mAh and the 18650 is only 1100mAh.
• They require a 3.6V charger.
• They have a nominal voltage of 3.3V versus the 3.6V/3.7V for the li-ion batteries we normally use. At high discharge current levels the voltage can be down close to 2.5V.

I hope to have the test report for the 26650 posted in a couple of days. I won't be testing the 18650 as its capacity is so low. For more information about A123 technology, LFP chemistry, A123 battery specifications, and working with A123 batteries:

Overview of A123's technology:
http://www.batteryspace.com/prod-specs/6610_1.pdf

ANR26650M1-B Brochure/Specs:
http://www.batteryspace.com/prod-specs/6610.pdf

APR18650M1-A Brochure/Specs:
http://www.batteryspace.com/prod-specs/6612.pdf

Cylindrical Battery Pack Design Guide:
http://www.formula-hybrid.org/wp-content/uploads/A123-Pack-Design-Guide-for-Cylindrical-Cells.pdf

 

[DaveP]

Thanks, Mooch. Your info is valued and appreciated in these threads.

Speaking of L-ion improvement, have you heard any estimates on when we will see new batteries that have improved protection against dendrite formation? I've read articles that talk about batteries in development that solve the dendrite issues.

 

[Mooch]

Thanks, Mooch. Your info is valued and appreciated in these threads.

Speaking of L-ion improvement, have you heard any estimates on when we will see new batteries that have improvement protection against dendrite formation? I've read articles that talk about batteries in development that solve the dendrite issues.

There have been ongoing improvements in that for a while now but I don't know if any of the cells we use have those improvements. Our biggest problem with any cell in development now is that they are all low-amp, high-capacity cells. This is, by a huge margin, the largest part of the battery market. Most of the developments we're hearing about won't be in affordable batteries that we can use over 15W or so. :-(

 

[TruckinVaper]

Another battery I'm looking forward to seeing you test

 

[Barkuti]

Nice to see you're wanting to deal with these, always wanted to know more about the true power delivery of such 26650's.
The ANR26650M1A is available in a 2-pack at FastTech for slightly less than $20; I see 'em at $20'22 including shipping after “BLF” coupon.
Also available for a cheaper price in aliexpress, yet can't really be sure what you'll be getting, imho.
Due to the lesser nominal voltage vs li-ions, I estimate close to a ¼ reduction in coil resistance in order to maintain the same power on it. Due to the increased current additional losses in other parts of the circuit of a high quality mod, 75% seems a nice figure; of course vaper I am not.
Looking forward for that crazy amps review.

Cheers

 

[Joergl100]

The actual Version of the 26650 A123 is ANR26650M1-B, the nominal capacity is 2500mAh, 70A maximum continous discharge, 120A maximum pulse discharge. I'm using only this batteries with my 26650 mechanical mods; i'm loving it! Can vape at incredibly low resistances...down to 0,05 ohms with no problems at all! I'm using them since one year...they are still in pretty good condition.

Nice thing is the discharge characteristics: continous voltage from fully charged until the end...then goes down very rapidly. Continuous power all the time! Not a curve, straight instead!

I accidently killed one of them, there was a short circuit...my fault (hybrid adaptor...). It just got hot as hell...and was dead....really silent.

I am excited...awaiting a test by Mooch!

Sorry for my poor english, i am german.

In germany they cost about 10€...is nearly the same as 10$. Absolutely worth that!

I wouldn't buy that "old" ones from fasttech.

 

[Mooch]

The actual Version of the 26650 A123 is ANR26650M1-B, the nominal capacity is 2500mAh, 70A maximum continous discharge, 120A maximum pulse discharge. I'm using only this batteries with my 26650 mechanical mods; i'm loving it! Can vape at incredibly low resistances...down to 0,05 ohms with no problems at all! I'm using them since one year...they are still in pretty good condition.

Nice thing is the discharge characteristics: continous voltage from fully charged until the end...then goes down very rapidly. Continuous power all the time! Not a curve, straight instead!

I accidently killed one of them, there was a short circuit...my fault (hybrid adaptor...). It just got hot as hell...and was dead....really silent.

I am excited...awaiting a test by Mooch!

Sorry for my poor english, i am german.

In germany they cost about 10€...is nearly the same as 10$. Absolutely worth that!

I wouldn't buy that "old" ones from fasttech.

Yea, the M1-A's are the older cells. I recommend only buying the M1-B's. They have a slightly flatter discharge curve too. A nightmare for battery management system design but great for mech use.

 

[Joergl100]

Fortunately, the one i killed...was one of the M1-A's...

 

[Barkuti]

The actual Version of the 26650 A123 is ANR26650M1-B, …
In germany they cost about 10€...is nearly the same as 10$. Absolutely worth that!

I wouldn't buy that "old" ones from fasttech.

WTF? The “actual” version is “B”? Sorry but, the “A” revision is no less real than the “B”.
The “B” @#$% is just a slight capacity improvement over the old version, afaik.
You wouldn't buy those “old” ones from FastTech? Why? Could you provide at least a link to a reputable seller selling “Bs” at a reasonable/competitive price? Thanks.
Thank thee.

Regards,
Salvador

 

[Joergl100]

I buy them at NKON, NL or akkuteile, Germany. I don't know other possible sellers...but I live in Germany.

Datasheet M1-A

Datasheet M1-B

 

[Barkuti]

Ooops! It was Mooch who was recommending buying the M1Bs over the M1As, sorry!
Too much boozing on wine and beer last night, definitively.
By the way, the APR18650M1A was already reviewed by HKJ some time ago on his old rig:
Test of A123 18650 1100mAh (Yellow)

I wonder why the discharge curves seem to start at around 3'45V, when these batteries are supposed to be charged to 3'6V (or slightly more) safely. Did he failed to fully charge them? Cos that would somehow explain the low capacity…
On a side note, the Soshine IFR26650s may also be worth testing too ($23.50 Authentic Soshine IFR26650 3.2V 3200mAh Rechargeable LiFePO4 Batteries (4-Pack) - test capacity: 3112.9mAh / 30A continuous discharge current at FastTech - Worldwide Free Shipping). I must admit the wrapping seems very very similar to that of the LiitoKala 26650s/Soshine NCR26650s, my bet is these may be produced at the same facilities so, given the great performance of the li-ion cells, the LiFePO4s should do quite nicely at a great pricepoint.
Cheers

 

[Joergl100]

I recommended that too...

That Soshines...really 30 Amps? Only datasheet I found: http://www.soshine.com.cn/upfile/20129/20120916083811786.pdf

And...there they write "30A": http://www.soshine.com.cn/a651.aspx

That sounds kinda strange for me:

Internal impedance: (1kHz AC) 45 mΩ

Isn't that a little bit much for 30 Amps? Maybe I am wrong.

 

[Barkuti]

Joergl100, 45mΩ is certainly a lot, but I really doubt those figures. They claim 15A for the NCR26650s, which certainly look like the LiitoKalas, able to provide 20A.
For the IFR26650s to perform well at 30A, they would certainly have to provide slightly less internal resistance figures to those of VTC5s in order to keep adequate power output, I believe.

Cheers

 

[Joergl100]

Forget it...this is a - same, as usual - bad bluff!

Wait for the tests...

 

[Barkuti]

Hello!
With regards to the aforementioned Soshine IFR26650 batteries, just found this: 3.2V 3000mA动力型磷酸铁锂锂电池 生产厂家｜东莞力朗电池科技有限公司
Maybe they aren't bad bluff.
Any of you vaping with a 2S battery pack? BMSes are quite inexpensive nowadays…

Cheers

 

[Joergl100]

There are 2 Batteries with 3200mAh: IFR26650-32A with a maximum discharge of 5C, which means 16 Amps, and IFR26650-32B with a maximum discharge of 3C...9,6 Amps. Nothing with 30Amps.

 

[Barkuti]

Already saw that, Joergl100. This graph, however, clearly shows a nice looking “10C” curve which, unless quickly sketched with Windows Paint, makes me think that either the table is obsolete, or the graph above has some typos.

Cheers
P.D.: internal resistance is claimed to be <16mΩ on the product page. A plausible figure for a 30A LiFePO4 battery.

 

[Mooch]

Hello!
With regards to the aforementioned Soshine IFR26650 batteries, just found this: 3.2V 3000mA动力型磷酸铁锂锂电池 生产厂家｜东莞力朗电池科技有限公司
Maybe they aren't bad bluff.
Any of you vaping with a 2S battery pack? BMSes are quite inexpensive nowadays…

Cheers

The huge drop in the nominal voltage and the 65°C temperature at 30A shows it's not a 30A battery but it's probably near 25A. Germany likes the A123 in series. Just charge externally and no BMS needed.

 

[Joergl100]

There are 2 batteries with 3200mAh...and the ratings are readable in the table at the site.

最大放电电流 translated:
Maximum discharge current!

The Battery with -30A...has 3000mAh...reminds me to Samsung, like 30Q...25R...etc., it has a maximum discharge current of 5C, which is 15 Amps.

That graph looks a little bit strange...in my opinion.

 

[Barkuti]

The huge drop in the nominal voltage and the 65°C temperature at 30A shows it's not a 30A battery but it's probably near 25A. Germany likes the A123 in series. Just charge externally and no BMS needed.

Well, it seems you're a bit strict with the amp ratings, certainly because of demanding temperature and voltage drop margins. And since P = I²R, its easy to understand that, for any given possible maximum dissipated power in the battery, increasing the maximum output power/current means need for massive reduction in battery internal resistance. Really nothing to complain, I would also not feel comfortable handling a HOT battery stuffed device, and much less putting mechanical mods and/or some sort of “experimental”/safety measures deprived device in the hands of some berzotas (hell, thank God I warned certain chaps from restoring power tool battery packs using NCR18650Bs and/or laptop pulls).
Germany? What? Do you mean there's some sort of A123 batteries in series german vape club?
By the way, plenty of Aliexpress/eBay sellers offering ≈$1 voltmeters working at crazy low voltages, great and inexpensive way to monitor the battery voltage.

Cheers