The (suspected) truth about VictPower cells

[circuit]

I'll start with my general observation first. I have some A123 20Ah pouch cells lying around. These were 'quality cells' (bought not from VictPower), measured exactly 20.0Ah. Due to long storage and some test equipment being hooked up, some of them got self-discharged (down to 0.2V) over the time and puffed badly.
So I decided to make a test with them. Charged at 0.5C rate fully. ~18Ah went in (notice a drop from previous 20Ah). And left them to rest for a month.

And guess what. A month passed and all puffed cells are no longed puffed. Swelling reduced to almost original state. Capacity dropped to 18Ah, permanently. The victims still have some wrinkles as a proof of previous puffing. Also their Ri increased from ~0.9mΩ to 2-3 mΩ.

Now, here's my theory: VictPower sells crappy cells, that they get for scrap metal price. Usually these cells are puffed, so they pre-charge them a bit and ship out. Many of their cells have wrinkles or mechanical damage, as well as very different tabs: ones have perforation (fuse), others don't, some have badly cut perforation and some of cell's foil cut-off, some have unevenly cut-off tabs, that are a dead giveaway they were removed from a pack.

Received a pallet of cells from client, who bought them from VictPower.

So, all of you measuring "18Ah" capacity... You get what you pay for. Junk.

 

[circuit]

Here you go. The pallet from VictPower is full of cells like this one:

Think twice before buying from them. And it's not like you can get your money back.

 

[heathyoung]

You know, you may just be onto something here.

They are too expensive as well to be honest, for what they are - I was pricing these for off-peak grid storage (load shifting) - with their postage price, they are no cheaper than locally sourced 60AH thundersky cells (yeah I know but they are only seeing peaks of 1C, and usually running at 0.2C). There is a warantee with the local cells as well.

For peak power - great, long term energy - not worth it.

 

[neptronix]

I heard a story about these being rejects from the line that produced the cells for the Fisker Karma. They were going to be recycled but ended up in China, then sold.

I also heard that the cells cost about $65 brand new in quantity. So there's no way these cells are anything like new.

Jack Rickard got some cells that puffed and popped.

 

[liveforphysics]

And guess what. A month passed and all puffed cells are no longed puffed. Swelling reduced to almost original state.

This is most interesting to me. The decomposition of materials can not re-combine from adding the voltage back. You should be able to stop further decomposition, but not re-combined the off-gassed products of decomposition that produced the puffing in the first place.

In my experience, when a cell puffs, and then de-puffs, it happens because it puffed so much that it finally failed its seal with a pin-hole somewhere and it leaked down the gasses until things lay flat-ish again. It would be great if you could check for mass loss if you have a high precision scale.

 

[Trackman417]

And guess what. A month passed and all puffed cells are no longed puffed. Swelling reduced to almost original state.

This is most interesting to me. The decomposition of materials can not re-combine from adding the voltage back. You should be able to stop further decomposition, but not re-combined the off-gassed products of decomposition that produced the puffing in the first place.

In my experience, when a cell puffs, and then de-puffs, it happens because it puffed so much that it finally failed its seal with a pin-hole somewhere and it leaked down the gasses until things lay flat-ish again. It would be great if you could check for mass loss if you have a high precision scale.

A dont believe a high precision scale, would do much, unless if you measured the weight of the pack before hand.
I do agree with the pin hole theory. A month is a lot of time, for something to leak, especially when you are dealing with gases.

 

[ohzee]

Yea sounds possible to me. Still as said you get what you pay for and since I paid a 1/3 at least of what id have
paid otherwise and got a summer worth of use out of them I still don't feel like I got too screwed..

I'm having some issues now but im pretty sure it's bms related.. anyway I still think it's a good thing to figure out.

I also did have one cell that tested fine originally puff up as big as you could imagine.. was strange.

 

[Sancho's Horse]

I am marginally interested in the whole Victpower thing. Especially with the sale of A123 to Wanxiang. If they hold their contracts with the automakers in the US (which I haven't researched), there will be a strong pressure not to release the cells to home hobbyists. The threat to car profits if a poorly made/maintained DIY battery were to make headlines in some tragic way is not something I think most US car makers would tolerate.

In China though, it is an entirely different story. Some idiot goes poof, or some misfortune happens, well that is what happened, not some political theatrics like we get here, and definitely not some lawsuit turned retirement plan. I really think there may be a market for these in China, especially now. So...how do you satisfy the Chinese market and western automakers? Back door, black market "recycling" shops. Then if there is a problem, it was backdoor, black market, poorly made junk, not what you just bought with your new electric vehicle.

Victpower obviously has some connection to the product chain, even if it is the garbage man. I am not so sure though, adn it may change with the recent acquisition. I am planning on going to China in a few months, and the rep from Victpower asked if I would stop by their factory. It is a long ways from Beijing (try the entire coast away) but I am considering going. These batteries may have then length of life and a bit higher c rate to get most people to the next great chemistry safely, so...why not check it out?

I think puffed could become unpuffed. My sons balloons do it all the time.

 

[circuit]

The cells im question are perfectly intact, no mechanical damage. There were only slightly puffed cells, too. I dont' know where the gases went, if it is chemistry related or simply vented out through foil's holes in molecular level. But since it is a quite thick layer of aluminum, I doubt it.

 

[Doctorbass]

To help giving a neutral review of them in that thread i think i shold bring my contribution by sharing my experience with these cells:

In this video below i'm showing how stable are my cells that i bought from victpower last year.
I had tested them in march for capacity and internal resistance ( with old crapy RI meter but their result was pretty accurate over the cells. I recall that we had ordered over 130 cells and we took 10 randoms cells to test their real performances. In the following video i proceed to measure their voltage and internal resistance and overall shape to show you how stable they are from cell to cell and how they preserved their shape without any sing of leak or current leak or any change in their original physical and electrical state.

The result is that over all 10 random cells from the 130+ qty, all their voltage is with in +/-2mV and their internal resistance is under 0.8miliohm ! ( the RI tester now is a professional grade from HIOKI and worth over 2000$ and it give the REEL Ri result!

The cells still look strong and sealed just like when i received 9 month ago.

I can say i am really satisfied with these results.

About teh capacity test i will retest them soom, but i can say that usually with stable result like that i'm pretty sure that it doesn't changed at all.


I have made a video showing the result:

[youtube]Nxi5rQnN-b0[/youtube]

 

[circuit]

Were you using them during the time, or were they just lying around?
O wonder how many cycles these can hold until drops to -10%.

It looks like VictPower is getting low on stock and now sells all tje junk that was layed off as defectd previously.
Anyway I've seen enough '0V' cells from them a year ago, so you might just got lucky or missed the junk ones during random selection.

 

[Sancho's Horse]

When they found out that I would be in China, they asked me to come to the factory. I did not ask them. They did not know exactly when I was going to be there, but...when I told them it would be three months in the future, there was no hesitation, they wanted me to stop by. So...I think there must be some confidence that they can get more, and...there must also be some confidence in what I am going to see, so...take it for what it is worth. I don't have any of these cells, so...I don't really have any experience to judge their value one way or the other. I am hoping that they have good product. I am there for family business, so...that will take precedence. But...hopefully, I can get down there.

 

[RayGo]

You mentioned earlier that the cells you got from Victpower dropped from 20ah to 18ah. I just got some cells from Victpower and was wondering how to determine the capacity of my cells. Can you suggest an easy test method to use to determine each cell's amp-hours? Thanks.

 

[liveforphysics]

As a data point, the first of the AMP20 cells we saw on this forum, the samples Cellman sent me, did have ~19.5Ah from the AMP20 cells, and about 17-18AH from the AMP16 cells if my memory is correct. I remember finding it odd that the 16Ah cells over performed the spec, and the 20Ah cells under performed the spec (by a small bit).

May or may not be relevant data, but it does seem odd that the VictPower cells seem to be the identical physical size and impedance, but seem to do ~18Ah (from other folks testing not my own, I don't have any VictPower samples here). If a 19,5Ah cell drops to 18Ah capacity after getting drained down to 0v and then recharged, that seems somewhat likely that they may have been discharged.

I wonder if before A123 ships them to a recycler, they discharge them to 0v first before shipping, and then the recycler just opens up the crate of stuff to recycle, and just throws them on a trickle charger to revive them, then sells them.

If you were going to revive any cell, the A123 M1 26650 cells I remember were amazingly durable at being discharged clear to 0v and making a pretty solid recovery and still performing well afterwards, the indicator with the little 26650 cells that had been drained clear to 0v and sat at zero for a while before being recharged was they wouldn't hold that little surface charge to 3.6-3.7v for weeks/months anymore like a new one does. Are folks seeing that behavior on these cells by chance? As another datapoint, the early AMP20 pouches sent to me from cellman 3-4years back would hold that 3.7v surface charge for months.

 

[etriker]

As a data point, the first of the AMP20 cells we saw on this forum, the samples Cellman sent me, did have ~19.5Ah from the AMP20 cells, and about 17-18AH from the AMP16 cells if my memory is correct. I remember finding it odd that the 16Ah cells over performed the spec, and the 20Ah cells under performed the spec (by a small bit).

May or may not be relevant data, but it does seem odd that the VictPower cells seem to be the identical physical size and impedance, but seem to do ~18Ah (from other folks testing not my own, I don't have any VictPower samples here). If a 19,5Ah cell drops to 18Ah capacity after getting drained down to 0v and then recharged, that seems somewhat likely that they may have been discharged.

I wonder if before A123 ships them to a recycler, they discharge them to 0v first before shipping, and then the recycler just opens up the crate of stuff to recycle, and just throws them on a trickle charger to revive them, then sells them.

If you were going to revive any cell, the A123 M1 26650 cells I remember were amazingly durable at being discharged clear to 0v and making a pretty solid recovery and still performing well afterwards, the indicator with the little 26650 cells that had been drained clear to 0v and sat at zero for a while before being recharged was they wouldn't hold that little surface charge to 3.6-3.7v for weeks/months anymore like a new one does. Are folks seeing that behavior on these cells by chance? As another datapoint, the early AMP20 pouches sent to me from cellman 3-4years back would hold that 3.7v surface charge for months.

In a time when things are amazingly not durable the A123 m1 26650 cell is in a class of its own.

I am still running a pack made from dewalt pack cells from 2006.

Working in electronics repair it sure looks like stuff is designed to fail in about 2 or 3 years.

That and the got to get the latest new and improved toy keeps the people buying.

 

[999zip999]

Raygo your usable capacity changes as how you use it. My capacity test comes from a C.A. 30amp Lyen and a 9c 2810 full throttle almost all the time and get 18ah almost. This is what I get as How I can test.
I did replace one A123 cell in a pack on the rear rack laying flat and not well protected or when building a little ruff on the bottom cell on the table. Meaning it was the first one down and all work was on top of it. It race to to charge up and depleted first. It was a end cell on my rear ruff riderrack so to spreak. It also was a little sprongie.
As for China they are only a few people who know the true place where these cells come from. We are building cheap ebike batteries and everybody wants it cheaper. This is why most people first come to E.S. because of buying a to cheap of a battery.
Victpower 20.00usd A123 20ah 2-3k left so hurry. Lot's of bang for the buck for bikes. Cars ?

 

[grindz145]

If it's between these and thundersags... you're probably still better off with the AMP20. I'm trying to make a deicision for cell right now for my ninjafighter, and the AMP20s are still on the list. The big question would be longevity. How quickly will they breakdown. Probably not good...

 

[arkmundi]

The other night I rode up Skyline Drive at Green Hill to attend a celebratory event. Our Congressman, state Lt Governor and host of other politicos were celebrating having reached the goal of the Worcester Tree Initiative in planting 30,000 urban trees in the wake of the Asian Long Horned beetle attack here. The bus doesn't go there, so bike it was. A longish commute and essentially all up-hill, so the largest draw on my 12S A123 AMP20 pack to date, a mere 5 amp-hours. Like no problem!

When I got back, I checked voltage, charged and checked voltage again. The battery typically operates at 39.7V and charges upwards to 42V. Right now its 41.69V, but will settle in pretty quickly to 39.7V during operation. That's 3.3V per, pretty characteristic of these cells.

I bought my cells from Victpower. I appreciate their having built a salvage operation that put the cells on the open market for people like me. It made my ebike possible, giving me the amps needed to climb up the many hills of Worcester, the whole point of the build. Having wasted two battery packs in the process, the original SLA shipped with my kit and an AllCell li-ion replacement, I'm happy to have a battery pack that withstands hauling my fat ass up these bike-awful hills.

The only outstanding question is whether I'll get the 2000+ charge cycles expected out of this pack, and what the capacity will be at that time. I have no evidence to suggest I won't. Until such a time, I have nothing but confidence in these cells and my supply agent. I'm left wondering what motivates a thread like this at ES, in light of the many here reporting their good experience.

 

[circuit]

A longish commute and essentially all up-hill, so the largest draw on my 12S A123 AMP20 pack to date, a mere 5 amp-hours. Like no problem!

When I got back, I checked voltage, charged and checked voltage again. The battery typically operates at 39.7V and charges upwards to 42V. Right now its 41.69V, but will settle in pretty quickly to 39.7V during operation. That's 3.3V per, pretty characteristic of these cells.

I bought my cells from Victpower.

If you are trying to say something technical and accurate, you are doing a terrible job. Those number do not mean anything when tossed like that.
All VictPower is doing, they are giving a chance for some hobbyist to hive away their money.

 

[999zip999]

I hive money every day so just come by. It gose down the gutter just like everybody else it's the people in the gutter who get Rich. So 16.00 or 20.00 plus free shipping back to USA, Hell I will pay shipping. Thanks curcuit.

 

[Teh Stork]

To stay on topic.

I picked up 14 cells from Oatnet and the majority of them has these kind of wrinkles and defects, I wasn't especially satisfied with the overall state the cells were in - but Oatnet did sell them with no warrantee. So I didn't really have any big hopes for them. I'll add pictures this weekend of mine, I remember they look quite like yours. I haven't tested them in any way yet - but your hypothesis is very interesting Circuit. I have a mOhm meter, so I'll check if I can replicate your 2-3mOhm IR.

 

[miro13car]

maybe it is a bit off topic.
But I am wondering if anybody had similar experience
I bought AMP 20 from A123RC and from Victpower 12pcs. from both.
Victpower cells all marked A0 in the middle had much better /less sagging/ discharge curve than discharge curves of A123 RC cells marked B in the middle.
All of them.
Say what you want , think what you want but
I am sure the reason Victpower cells were better has to do with that marking.
I am almost sure AMP20 are graded at factory testing stations.
I run discharge on CBA all of cells during the same 2 days, resting voltage after charging all of them to 3.60V - 3.65V. Discharged untill 2.5V.
Victpower cells discharge curves stayed flat longer - close to 1Ah more capacity.
BTW I requested from Victpower only cells marked A0 and they met my demand - no bad vendor at all.
my take on "how do they get them" is that they are factory rejects for two reasons:
mechanical defects /folds, readges, bends/ and for electrical reasons namely min. capacity treshold not met, but for sure that cells are new.

 

[999zip999]

Can't be disgarded in usa landfill a nd Mexico won't take them and e-t ships going back to china anyway. Maybe china pays a dollar a peice for seconds ? That are going to the dump or have to pay to recycled them or make a buck ? Or ?

 

[izeman]

why not believe that those are recycled cells from bigger packs? why should they be discharged? how many defect packs would be needed to supply all the need there is for these cells?
i like to believe that those are fully functional cells that somehow found their way back into business. i never thought they would be new - but better get a top quality second hand product than a cheap copy. right?

btw: i ordered 42 cells last week from VP, paid, and got the info today that there are not enough cells left, and i have to wait for the next charge. that's a shame if you pay $200+ for fast shipping, and then supply is gone

 

[sendler2112]

i ordered 42 cells last week from VP, paid, and got the info today that there are not enough cells left, and i have to wait for the next charge. that's a shame if you pay $200+ for fast shipping, and then supply is gone

What is the cheapest price that you could have gotten your order for, cells and normal shipping? Loose cells or 7S3P modules?