Victpower battery pack after 1 year

[dnmun]

but you cannot use the kit with you battery. it seems the power is gone already so i am not sure what you mean about more power. your battery is dead. if you don't repair it then it is just junk. you don't have any other options that i can see. but i cannot tell how many cells are bad and you did not post up any capacity tests to show which of the cells is short. what am i missing? the battery is dead as it is now.

 

[cwah]

All cells currently hold a healthy 3.2-3.3V. Even the damaged one...

From the positive to the negative lead I have 65V output. So quite ok for the battery too.

My next step is to salvage ALL cells and perform capacity test on each of them in order to see which one I keep or throw.

Then move all healthy cell to OSN/Agnisum kit and add new cells from Victpower/OSN.

I surely have at least 10 healthy cell, don't I? :lol:

 

[Hillhater]

Why dont you do a capacity and discharge IR test on each cell as they are in the pack.
Then you will know if its worth the effort to replace cells.
buying these from Victpower etc is like throwing your money onto a poker table..
...except the sellers hold a stacked pack !

 

[RayGo]

Sorry to hear about the problems with your Victpower pack. I remember seeing pictures you and other users posted of the soldered construction of the packs by Victpower. That convinced me to stay away from that type of build and to build my own pack.

Anyway, just a heads up for you when salvaging the cells from your pack. Keep in mind that you will need at least 10 to 12mm of tab length in order to use the OSN kits. Check with Agniusm for his minimum tab length. Otherwise, you will probably have to use clamps such as in the first OSN build kit but without the board or the Zappy build on page 27 of the thread:

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=38761&start=650

 

[jonescg]

Oh this is funny :lol: . Sorry it's hurts that you spend $700 on a battery that failed, but really, you get what you pay for. All A123 that isn't coming out the door of an A123 factory is not worth persisting with IMHO.

I love this place, and I think Endless-Sphere is awesome. But some of the arses around here are tighter than those of a deep sea fish. If you are buying A123 cells for less than $40 each, there's every chance in the world they're the ones 'John West Rejected'. And when a 1 kWh + built pack can be sold for less than $800, you can be confident little thought went into the design.

IF you are going to go down the LiPo route, do it well and you will have a powerful battery for a few years.
If you want large format cells, buy the good stuff made by EIG, Dow Kokam, Panasonic and put them together using the best mechanical clamping system you can find. You will pay for it, but you won't be disappointed with puffers, leakers and rusters like this.

I have about 50 PMs from folks asking about my LiPo packs, and only a handful actually went through with it and bought them. I should start making them for free since no-one is willing to pay what they are really worth, let alone at break-even prices.

In conclusion, you get what you pay for. :wink:

 

[cwah]

Thanks for the warning guys... I knew it was a bit a gamble.. but hey.. cells are SOOO expensive, I need money to live!! :lol:

I'm decided to test the cells and salvage them, I just ordered the icharger charger to cycle them:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=6609

Raygo, I don't see why I need to clamp the cells with specific tool? Why can't I do that with tape? That's what has been done right?


Now, I'm thinking to maybe buy again from Victpower... lol. Their cells are the cheapest on the market. I remember when I got them for the first time they were fine. Many other members had good experience with their cells isn't it? It's just their pack construction that is shit.

 

[izeman]

i bought from victpower. cells are still good. they had one minor cosmetic issues and tabs had different lenght. till now they are running fine. look in my klein build thread for details in how i built the battery.
by 'clamp' guya are talking of the tabs not the cells itself.
if you remove all cells from the pack you must measure remaining tab lenght. them ask agniusm about his boards. osn one's are not bad, but are wider than the battery itself. they have an overlay of one cell width on each end making the pack unnecessarily bigger.
agnium's kits are the best available. the time i needed one he didn't have 24s available so i tried to copy his system. i did quite well, but i was a hell of work to do it. and his kit is of highest quality and done with cnc machinery and not handmade like mine.
i would NOT buy from victpower this time again. the batch i got was from grade b or c cells already. i don't think they have any good cells left. if you really wonna buy cheap again order from osn and ask for long tab cells.

 

[cwah]

Thanks for your answer. They are currently selling batch over 100's of cells at really discounted price. Something like 13USD/cell. I was considering it as I could get them home, test them, and if they are not good ask for refund with Aliexpress protection system. (seller is only paid when good are received properly)

The kit from OSN for a 20s cost about 35usd, it's a really cheap price. So I'll probably still use it, if my cells are good enough to use it lol. I have to desolder the cells and see if it would fit.

 

[cwah]

I'm starting to remove the cell, and I was wondering what is this black stuff on the cell?

How can I replace it and find new?

 

[izeman]

are you talking about this:

i've never seen this on any of these cells, and can't imagine what it is for?! maybe insolation? but on the other hand: normally there is nothing behind that tape that need's insolation ...
i would remove it first and see what's behind. if there is some damage foil or something not looking normal, than dump this cell.

 

[lionschasing]

stop selling stuff dude. we're here to help people. not sell.

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

 

[lionschasing]

take my advice from experience...don't bother with the puffed cell... it will only hold 300mah of charge, you will never be able to recharge it again. The cells that are semi puffed too have oxidation due to perforation of the foil - they TOO need replacing. I would get 4 cells from somewhere and fix your cell pack by crimp method, dont bother soldering.

All cells currently hold a healthy 3.2-3.3V. Even the damaged one...

From the positive to the negative lead I have 65V output. So quite ok for the battery too.

My next step is to salvage ALL cells and perform capacity test on each of them in order to see which one I keep or throw.

Then move all healthy cell to OSN/Agnisum kit and add new cells from Victpower/OSN.

I surely have at least 10 healthy cell, don't I? :lol:

 

[dnmun]

he cannot solder them anyway. not sure what that was about. the reason people have to use agnius and the OSN clamp systems is because the positive electrode is aluminum and you cannot solder to it. the people who assembled this pack may have done the alligator tooth crimp to the aluminum with a copper tab but that is not clear. they may have found special flux and special solder to solder the aluminum but it requires keeping all oxygen away from the contact when soldering. but if he has some solder left on each side of that bad tab then he can cut out the bad tab and connect the two tabs with a piece of wire that he solders to the remaining solder. but he just is not able to do that.

 

[cwah]

I'm starting to peel off the black stuff as said, it seems it's to isolate the negative lead to the cell?

It looks like the tab are reaallly short/non existent? I'm thinking to use a soldering iron to remove the cell. Would that work?


Dnmun, if course I can cut a tab and replace it with another cell. There are also some low temperature aluminium soldering kit to solder aluminium:
http://www.ebay.co.uk/itm/ALUMINIUM-BRAZING-soldering-welding-kit-LOW-TEMP-includes-flux-/390610384574?pt=LH_DefaultDomain_3&hash=item5af23176be

But I was thinking it would make more sense to desolder all cells and replace the whole board for easy repair? What do you think?

 

[cwah]

Ok, I'm ready

 

[cwah]

Hmm... it seems that my 30w iron is not powerfull enough... I have to leave it too long on the tab and it start to heat the cell...

Shall I get butane torch instead?
http://www.amazon.fr/Hyper-briquet-temp%C3%AAte-br%C3%BBleur-jet-flame/dp/B0067M2VIY/ref=sr_1_4?ie=UTF8&qid=1373806286&sr=8-4&keywords=butane

 

[jonescg]

:lol:

 

[cwah]

Noooo John, this pack cost me 700USD!!!!!

 

[izeman]

80w+ iron with a flat bed tip. what you bought is ok, but for smaller parts only. you will need a LOT of heat on a big surface in a short time.

 

[lionschasing]

potentially...this soldering iron has lasted me a year, http://www.aliexpress.com/item/60W-Welding-Solder-Soldering-Iron-Heat-Pencil-Electronic-Tool-PC-PCB-220V-Freeshipping-Dropshipping/568255099.html

I think it's the one they use in professional things they build in china, it's the one the 'industry' use, cheap, cheerful, can melt gobs of solder.
I was previously buying the 100watt and 80watt soldering irons - I bought SIX that all melted the tips off after a month or two, then this little gem cropped up, it gets RED HOT

 

[jonescg]

You should be able to unsolder the offending cells using an 80 W iron with a bevel tip. Use the solder sucker to remove any solder from the slot, making a clear path for the new tab to enter. What genuinely concerns me is the fact that the positive tab is aluminium, and solder does not stick to aluminium. If you do miraculously get something to stick, chances are you'll damage the cell through excessive heat.

$700 is a lot of money, I agree. And I believe you should try to salvage it as best you can, but it will be trouble for the rest of its days. The bin option hurts, but your sanity is worth preserving.

 

[circuit]

potentially...this soldering iron has lasted me a year, http://www.aliexpress.com/item/60W-Welding-Solder-Soldering-Iron-Heat-Pencil-Electronic-Tool-PC-PCB-220V-Freeshipping-Dropshipping/568255099.html

I think it's the one they use in professional things they build in china, it's the one the 'industry' use, cheap, cheerful, can melt gobs of solder.

You are not serious, right?

You will need something like this (300W):
http://www.somersetsolders.com/shopimages/3178-300-400-2.jpg

 

[cwah]

You should be able to unsolder the offending cells using an 80 W iron with a bevel tip. Use the solder sucker to remove any solder from the slot, making a clear path for the new tab to enter. What genuinely concerns me is the fact that the positive tab is aluminium, and solder does not stick to aluminium. If you do miraculously get something to stick, chances are you'll damage the cell through excessive heat.

$700 is a lot of money, I agree. And I believe you should try to salvage it as best you can, but it will be trouble for the rest of its days. The bin option hurts, but your sanity is worth preserving.

That's why I was thinking to salvage all cells and completely replace it with a new kit. Or I can ask OSN to send me a new pack for 700USD again :lol:

Shouldn't I rather buy a butane type soldering iron? It would give much more heat isn't it? Something like this:
http://www.aliexpress.com/item/Portable-9-in-1-Gas-Butane-Welding-Soldering-Iron-Torch-Set-Pen-shaped-Free-Shipping/464097711.html

 

[cwah]

Something like this should give much much higher heat as it goes over 1000C
http://www.ebay.fr/itm/SOLDERING-WELDING-GAS-REFILLABLE-BLOW-TORCH-COOKING-GUN-2-FREE-BUTANE-REFILLS-/130669141593?pt=UK_Home_Garden_PowerTools_SM&hash=item1e6c7cde59#ht_3859wt_1239

 

[jonescg]

Electric is fine, it just needs to be high wattage. 60 W would no doubt do it, but 80 W is better.

Circuit, I have a pair of 200 W irons I use to solder 2 mm thick and 18 mm wide busbars onto LiPo cells (with copper tabs). It takes about 5 seconds. I think 60 W will be OK for what he's trying, but more is better.