Victpower battery pack after 1 year

cwah · Jul 11, 2013

Hello all,

I purchased the an A123 20AH pack from Victpower 1 year ago. And I was very happy at this time. But now my pack stopped working.

I looked at the pack and the box expanded:

So I dismanted the pack and realized one of the lead was disconnected:

Thanks Victpower for this poor soldering job....

And also one of the cell is swelling:

It completely pushed out the other cell:

Now I need to replace this cell. I have few problems to solve:
- Find a good supplier for new cell
- Any idea how I can test each cell individually without dismounting the pack? What's the best tool/way to do that?
- And to replace cell, I just need an iron?

Damn Victpower lol

ps: To view the pictures clearly, you have to zoom out from your browser.

knighty · Jul 11, 2013

you need to shrink the photos, even zoomed out all the way they still don't all fit

upload them to image shack (www.imageshack.com) and they'll give you forum links to post here, so we can see thumbnails, then click them to see bigger versions

how do you charge ? and do you have a bms ? - it's probably easier/better if you just remove that cell and run one cell less... but it depends on the rest of your setup if you can do that

cwah · Jul 11, 2013

The cells have all been soldered, so it's not easy to remove it:

I'm running them through a 20s BMS and charge with a 1000W charger. Should be fine as the cell are supposed to handle much much more.

I'm quite disappointed by A123 cells, I was expecting perfecting perfect things for many years.

circuit · Jul 12, 2013

black oxidation can be seen on the side. Usually this happens when there is a leak between any terminal and that cell's foil. So it could be a mechanical damage, rubbing etc. Or the foil got shorted to one of tabs during assembly.

cwah · Jul 12, 2013

In which picture can you see black oxidation? Sorry my eyes are not expert at all

wb9k · Jul 12, 2013

Wow. What a mess. Your cell surely got puffed up because the broken connection caused the BMS to overcharge or undercharge the cell. The black decrepitation seen on the puffed up cell also indicates, as others have mentioned, an internal leakage path for current between the anode (NOT the cathode) and the pouch. It may have overdischarged due to losses from that problem, then got hot on recharge as the dissolved Cu (from the anodes) in the cell plates onto the cathodes, forming dendrites that eventually puncture the separator and short the cell internally. This can make enough heat in the cell to break down the electrolyte and form gas.

Whatever the case, I have to say the problem here is not cells per se (though these were likely rejected by A123 for an actual reason before Victpower ever got hold of them), but the extremely amateurish design and construction techniques used to build the pack. No A123 cell is intended to have the tabs soldered--ever. That right there violates all kinds of handling and design rules. It appears there's no real mechanism for establishing or equalizing cell pressure, and many cells look bent and misshapen from the method used to bind them together. Why don't they run them through a blender while they're at it?

I understand your frustration, but to blame the problems here on the cells just isn't fair or reasonable.

dh

cwah · Jul 12, 2013

I AM SO FRUSTRATEEEED.

How do I know which cell is still alive? I don't have any charger/balancer anymore

Do you mean the black mark on the damage cell means electrolyte leakage?

How should the pack be created then?

Lipo seem finally to be a better option

best

davec · Jul 12, 2013

sure the pack was not built properly - if i recall a properly built amp20 module has cells standing up & also has the cells wrapped in a small casings with a compression belt .....also the tabs are professionally laser welded to bus bars- and the best of designs on here dont solder the tabs - but clamp
but regardless- it is the cells- i doubt it's the bms
i have been telling everyone on this forum for over a year that these grey sources are garbage
1. the CBA tests done confirm that they fall short on performance and 2. the cosmetic damage they come with is not pretty
im glad i got rid of mine before they puffed to death and going forward i will be buying legitimate even if i have to pay more
w9 being from a123 you should be aware of this link:
http://info.a123systems.com/contact-us-purchasing-cells/

cwah: if they start leaking get rid of it the msds on electrolyte is not pretty- with the puffed cells in this pack not sure how much of it can be salvaged

cwah · Jul 12, 2013

how can you buy legitimate cells if A123 are not selling them??? the pack was very expensive over 700USD and I don't want to throw it away???

and the pack was compressed firmly with tape so it wasn't supposed to move.

I'm so annoyed noww what should I do???

ambroseliao · Jul 12, 2013

You could ask Cellman if he would sell some single pouches or take your chances on Fleabay...

http://www.ebay.com/sch/i.html?_odkw=A123&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR7.TRC1.XA123+20ah.TRS0&_nkw=A123+20ah&_sacat=0

cwah · Jul 12, 2013

I was thinking to ask again Victpower as they have the best price and pack issues are related to the bad design?

or maybe OSN power for better cell quality?

dnmun · Jul 12, 2013

no way to tell what you are talking about since the pictures are too large. why not take them down and set your camera mode to VGA and take a picture we can see?

ambroseliao · Jul 12, 2013

I hope cwah doesn't mind! :oops:

Resized, levels adjusted and color corrected...

dnmun · Jul 12, 2013

that one pouch has shorted to the aluminum layer in the mylar and eaten away the aluminum. is it possible the black stuff on the soldered tabs is rosin from the solder and it was never removed? that is how it looks when i cook something with the soldering iron and the rosin burns.

when i repair packs, i don't try to pull the tab outa the slot. i just melt the solder and stand the tab up vertically with one tip of the the two irons i use. then i cut the edge of the little pcb connector in line with the slot so the pcb can be separated at the slot and the cell removed. then just install the new cell there and make the connection by soldering a short piece of wire across the connection after the new cell is soldered in place.

docnjoj · Jul 12, 2013

I do remember when spacey showed a photo of this type of construction I was appalled then, about a year ago. OSN has a kit and Agnius has the best assembly package in the world. My 12S split pack is still doing fine even after a year of regualr use. It is from Victpower cells and Agnius kits 2x6S. All cells balance and no puffers. I got long tab cells when they were first being advertised so they may be of better quality. I did have to replace one cell but I had bought 2 extras. So far so good.
otherDoc

edit: Unless I know the next A123 pouch cells were top quality I would probably buy Headways for my next battery. Also easy to assemble and easy to replace bad ones.

davec · Jul 12, 2013

cwah you're in the UK call up mavizen and see if they can help with a spare cell or two
personally i would not waste anymore more on this grey market crap- osn may sort them out better but they're still getting them from a dumpster just like everyone else is
put a voltmeter to each cell to see where they stand- also it looks like you will need to strip out the puff'd ones and solder a new one in---

cwah · Jul 12, 2013

docnjoj said:
I do remember when spacey showed a photo of this type of construction I was appalled then, about a year ago. OSN has a kit and Agnius has the best assembly package in the world. My 12S split pack is still doing fine even after a year of regualr use. It is from Victpower cells and Agnius kits 2x6S. All cells balance and no puffers. I got long tab cells when they were first being advertised so they may be of better quality. I did have to replace one cell but I had bought 2 extras. So far so good.
otherDoc

edit: Unless I know the next A123 pouch cells were top quality I would probably buy Headways for my next battery. Also easy to assemble and easy to replace bad ones.

Why agnisum kit is between than the one from OSN? The one from OSN looks simpler and doesn't need to drill any hole on the cells. Just plug and voila

Davec I'm not sure to buy from Mavizen are they are uber expensive and this pack is made of cheap A123 anyway

ps: Thanks for resizing my pictures

docnjoj · Jul 12, 2013

cwah said:
docnjoj said:

I do remember when spacey showed a photo of this type of construction I was appalled then, about a year ago. OSN has a kit and Agnius has the best assembly package in the world. My 12S split pack is still doing fine even after a year of regualr use. It is from Victpower cells and Agnius kits 2x6S. All cells balance and no puffers. I got long tab cells when they were first being advertised so they may be of better quality. I did have to replace one cell but I had bought 2 extras. So far so good.
otherDoc

edit: Unless I know the next A123 pouch cells were top quality I would probably buy Headways for my next battery. Also easy to assemble and easy to replace bad ones.

Click to expand...

Why agnisum kit is between than the one from OSN? The one from OSN looks simpler and doesn't need to drill any hole on the cells. Just plug and voila

Davec I'm not sure to buy from Mavizen are they are uber expensive and this pack is made of cheap A123 anyway

ps: Thanks for resizing my pictures

It is easy to punch the holes with a paper punch hand held for agnius's kit.. I'm not so sure it matters unless we can find a reliable source of good A123 amp20 cells, cwah. It is too bad that they are going downhill now.
otherdoc

dnmun · Jul 12, 2013

unless you have the proper equipment, flux and skills it is impossible to solder the tabs back in there like i do with the ping packs. your only option is gonna be to hack the pack down in size and use the solder that is on the end of the old tab to make the connection across to the next pouch and just cut down the pack in series to 13S and hack the BMS to 13S to protect and balance it. it was 3 cells that are bad?

cwah · Jul 12, 2013

docnjoj said:
It is easy to punch the holes with a paper punch hand held for agnius's kit.. I'm not so sure it matters unless we can find a reliable source of good A123 amp20 cells, cwah. It is too bad that they are going downhill now.
otherdoc

I think I'm going to buy again from Victpower and do like everyone else:
Cycle them few times to check their capacity. It's almost 2 times cheaper than OSN. And probably something like 3 times cheaper than Mavizen.

I understand how to punch hole, but I don't see how it can be better than the one from OSN power that doesn't need any punching and is cheaper? What's the benefit over them?

cwah · Jul 12, 2013

dnmun said:
unless you have the proper equipment, flux and skills it is impossible to solder the tabs back in there like i do with the ping packs. your only option is gonna be to hack the pack down in size and use the solder that is on the end of the old tab to make the connection across to the next pouch and just cut down the pack in series to 13S and hack the BMS to 13S to protect and balance it. it was 3 cells that are bad?

I don't know how many are bad. I have to test them.

I'm still wondering where I can find good cells for battery? I'm thinking to get the 4s hardpack from Hobbyking they seem to be the most reliable and easy to change?

ambroseliao · Jul 12, 2013

I don't think Hobbyking sells the A123 pouches... I may have misunderstood you, cwah...

cwah · Jul 12, 2013

ambroseliao said:
I don't think Hobbyking sells the A123 pouches... I may have misunderstood you, cwah...

I mean stop using the A123 pouches and only use HK lipo as battery pack? Would be somehow simpler to fix and cheaper even if it only last 2 years

dnmun · Jul 12, 2013

why not just hack the battery down to 13S like i said? if you only have 3 bad cells then you could still make it work, maybe you would need a new BMS for 13S if you can't hack that one down. but you can adjust the charger down to 47.5V or so and then use it as a 13S pack. should still work.

cwah · Jul 12, 2013

dnmun said:
why not just hack the battery down to 13S like i said? if you only have 3 bad cells then you could still make it work, maybe you would need a new BMS for 13S if you can't hack that one down. but you can adjust the charger down to 47.5V or so and then use it as a 13S pack. should still work.

I don't want to loose power. It's a 20s battery and I sometime is thinking to hack it up to increase voltage and speed lol.

I'm thinking to get additional cells and the kit from OSN (unless anyone tell me how the one from Agnisum is better)

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