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A123 20AHr Pouch Cell Battery Build & Info Thread

999zip999 said:
Stop with Nancy or April. Her name is Nancy and her E.S. name is April as yours is Dnmun. Clue ?
Cellman name is Paul right ?
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Whats that about? Does it really matter, Nancy Shmancy or April and Spring?... :D
 
Got all these guys arguing on what name to call you by, funny because most members use a nickname not a 2nd real name :D
Can you supply kits with those extra plates and slightly longer screws to match, it could fix the design flaw and help draw more amps without concern.
 
I sent an email to OSN about the kits. I've been waiting to build my second pack because I don't have enough spare time, but that kit would be easy and fast.
 
Need to buy a few packs to win :D.
 
999zip999 said:
I just remember seeing victpower soldering the tabs togethere and soldering the end termenations like the alumiun to coopper wire. As that would stick. I just can't find the photo. I don't know of a solder that would work with alumiun and copper so it worry me. Do I remember as I can't find the photo ?
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You mean this one? what a waste of time and effort fixing these packs!

file.php
 
Yep I remember it too! Thanks Spacey for reminding me what it looked like.
otherDoc
 
My 24s as two 12s and was in storage for 4 mos. all 3.338-3.318v.. I charged it on the 1420 all at 3.59v and seen fairly well balance during charging. So after a 4.5ah ride the one cell on the bottom of the rear rack was 3.281 and the rest at 3.311-3.308v.. This was the cell I replaced 7mos ago. I did buy 25 cells and tried to use the best of the 24. So if I didn't use it then and keep it for the replacement cell it might have been a little dodgy one ?
Has anyone replace more then one cell in a pack ? Will see if it perks up a little in the next week of riding. These are full tab from Victpower in the early days of group sales.
 
I already have 36S3P battery pack made from full tab "USA made" cells from OSN.

For other project I need 52 cells. So, what do you think about those "made in Korea" cells?
They are cheaper then "USA made" cells. 18$ vs 30$ :?:

Battery pack is for hard enduro motorcycle. I need around 85V and 40Ah.
 
How many different grades and prices of A123 20ah OSN cells do you know of ?
The short tabs USA and Korean with the holes in the tab or tabs ?
Full tabs but used.
Full tabs USA new.
 
The US plant caused the recall issue due to an incorrectly set welding machine.
 
My first pack was from new "USA made" full tab cells.

Now they offer me:
18$...brand new, made in Korea, full tab, 1 tab with holes
30$...brand new, full tab, "made in USA"
 
A123 said they werent sure which cells came off the faulty line.
Seems strange when they have what appears to be batch and serial numbers on them Zip.
 
999zip999 said:
Tomaj where do you get your cells and when. How"s the pack working out ?
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Those "made in Korea" are C grade with short tabs, but they claim they are new and offer the warranty. I am probably going to take USA cells with full tabs.

Actually my first battery pack has 0 cycles :wink: My electric motorcycle will be completed in two weeks. I bought the cells from OSN Power a year ago.
 
Megacycle I thought the same thing I guess they were making cells and with restrictions on sales ect. The cells were just stacking up in the warehouse till they open the back door.
 
I was thinking it was more battery related than cell level.
Said the tabs were not aligned correctly, wouldn't be welds internal to the cell? info overload again.

Yeh there would have been a huge pile of cells following the recall, how many are still available?
Are they still churning them out of the other plant?

I'm looking at wanting a ton now.
They seem to be proving themselves well for long term app's.

The ext blend might be good to look at now for climate extremes, if the price is right.
 
A few weeks ago I received my 28s3p pack from victpower all cells at 3,23v all without BMS and I was charging some cells (3 p ) to about 3,5v to see if they kept the voltage at 3,5v overnight.

I didn't look at now for a few weeks and all cells are exactly 3.23v again,the cells that were on 3.23v were still the same. is this a good voltage ? Maybe this a resting voltage for these A123 cells, I am used to Lipo cells, and they drop from 4,20v to about 4,18v and maybe after a few weeks they are 4,17v.

So I wonder if this from 3.5v to 3.23v dropping is normal and 3.23v is still about 95% state of charge ?

I am about to order 9x 7s3p packs from Victpower so I want to be sure about this.
 
bigmoose said:
I snagged one of the battery termination kits that ambroseliao purchased and described a couple of pages back from Nancy at OSN Power. I find it well made and would have used the same words he did in describing it. Using his picture, it is the same kit:
file.php


I bought it because my scratch design was 90% similar to theirs in form and function, and it sure saved a lot of work on the milling machine!

What I will add is Nancy from OSN was just a great person to deal with. Her english is 100% and I found her extremely helpful and responsive. Kit came a little over a week from my purchase date. All in all an A++ transaction for me.
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Bigmoose, These kit look interesting due to the easy and fast way to assemble the pouches. Do you agree with me that it would be only recommanded to use with low to medium power ?

There is two importants points i think that make them more risky for high amp ( let say 50+ amp)

First , I believe that the pressure uniformity on the tab width is weak. The two screw at each end will make the conductive top bar to bend and not have the same pressure on the center as the pressure on the sides near the screw. There is no screw to push to the cell tab to all their width. so the contact is not made on 100% of the tab width and i think it is way lower than what it look like. if you torque more the screw, it might get worst.

And, in electrical engineering, having high current conductor in sandwich between plastic and metal is not a good idea due to the possibility that the plastic soften depending on the temperature, reducing the pressure on the cell tab and increasing the contact resistance. And as the plastic soften, as the contact resistance goes higher and that loop could result in hot spot or melt plastic and even create a fire if the current is sustained. cheap chineese plastic are not fireproof i think. That kind of sandwich was what few years ago have made one of the Hymotion plug-in hybrid Prius battery to burn to the ground due to bad electrical contact desing with a screw torque between metal conductor and plastic battery case.

That’s why I preferred to buy some of the kit that Agniusm made wich are excellent to me but are a bit more expensive and require more assembly time, but I think it worth anyway.

The agniusm kits are not using plastic but FR4 ( pcb fiberglass material) with does not soften at the temp range the battery tab can reach, it is more hard material. And also the sandwich conections is made with two aluminum bar and 3 screw that spread perfectly the pressure along the cell tab width wich guaranty the electrical resistance to keep low and stable.

What do you think?

Doc
 
Guys.
I just dug through a lawsuit file against A123, on the AMP20 pouch cells. Downloaded the original document from stanford.edu.

It's 66 pages long. Here is my take away:

1. The original AMP20 is made in Korea. The Korean cells seemed OK. The US operation was setup later with Korean process.
2. Majority of the AMP20 cells made in US did not meet the quality control spec. Using a US AMP20 cell is like playing the Russian roulette.
3. A123 knew they had a quality control problem and covered it up.
4. The US made AMP20 cells may have bad electrode coating.
 

Attachments

  • 2012831_r01c_12CV10591.pdf
    2.8 MB · Views: 116
Please remember that these are allegations and need to be proven.
 
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