repairing A123 victpower package, anyone?

dutchlincoln · Mar 2, 2013

Hello,
I have a 16S2P victpower battery that i bought from a friend that imports these.
A few days ago, i discovered a significant decrease in range of my electric moped scooter.
When i eventually opened the package, several cells were puffed. Some were t least 3 times increased in thickness...
Now, i want to repair the pack, and when possible, buy new cells for it.
These cells however are soldered together on a printed cirquit board.
I read somewhere there was more expirience with this, and some repaired them.
Gan anyone give me some advice and tips in order to repair this?

Thanks.

I will add some pictures later on.

999zip999 · Mar 2, 2013

Yes we can help. You first need a big soldering iron like 80watts. So go find one and give pic's lot of pictures.
Dutchlinclion where do you live ?

dutchlincoln · Mar 2, 2013

some pics:

999zip999 · Mar 2, 2013

DO NOT remove the bending tape !!!

999zip999 · Mar 2, 2013

First find the bad parelle's.

999zip999 · Mar 2, 2013

I heat the solder and fling it down on to a broad. Half when heating up the solder. Or cut the board. Ouch !

999zip999 · Mar 2, 2013

Or go buy some Agniusm's A123's setup's or the OSN model's style ect. And be able to clean things up a Little. Oh for the buss bars ? So my style.

999zip999 · Mar 2, 2013

Or go buy some Agniusm's A123's setup's or the OSN model

dutchlincoln · Mar 2, 2013

999zip999 said:
DO NOT remove the bending tape !!!

Uuuuh.....
I need to remove the tape in order to disassemble the pack...?

What would you do then?
Why not removing the tape?

Currently discharging them with a RC charger in order to determoine the capacity.
I discharge them to 3.0v Is that correct?

999zip999 · Mar 2, 2013

I said that as the cells can puff and rip off the taps of good cells and you can only watch as the cell expells or puffs as sone as it's cut.

999zip999 · Mar 2, 2013

How do you stop popcorn in the mircowave ?

999zip999 · Mar 2, 2013

Maybe your's just puff a little we are talking about a 20ah cell what is full puff ? One pillow or three ?

arkmundi · Mar 2, 2013

I'll second the motion that the plan be to salvage the usable cells and rebuild the pack with better tech - either Agnisum's kit or the OSN one. Yes, you'll need to remove all the solder as the first step. Do so with extreme caution as you do not want to short circuit the cells. I'd use a good solder gun and a basic solder sucker. Suction off all the solder, leaving not a trace. Your method for doing so will be critical to success, so experiment first to the hang of it.

After you've removed all the solder, you should be able to separate all the cells. Test them all to see which will hold a charge and which will not. Puffed cells may or may not have failed. I'd go back to Victpower for replacement cells. Good luck!

999zip999 · Mar 2, 2013

Thanks Arkmuundi as it hurts to type. The cells are very a live and hot. long time.

agniusm · Mar 2, 2013

What a bloody mess. Victpower pack building in all its glory

The aluminium tabs should clean pretty easy, plated copper ones bit harder. Teflon coating near the place where tab meets the cell is tough enough.
As said above, clean it with white gloves on, in debris free environment to avoid further puncture of OK cells. After done, look around for black spots on the edges around the OK cells, if found leave it aside. Charge to resting voltage and let them sit for couple of weeks. Get replacement cells + 4 if something goes wrong. There is no need to spend more money for full tabs at 30$ at this stage i suppose.
Boys, he has 2P setup so my or OSN kits wont do. I do have a design on paper to go 2P thou and manufacturing is on the way if someone needs it

Get some benefit out of puffed cells so we all can learn. Overcharge them on camera, put it on youtube, link here. I have not seen video on overcharging these. Need to have data if they catch fire when overcharged!
P.S. For one off i would need to make blocks DIY thou.

dnmun · Mar 2, 2013

if you have two voltmeters you can use one as an ammeter and the other as the voltmeter and discharge each cell into a big power resistor or light bulb. you charge it up to 3.65V first and then discharge to 2.1V to end the capacity test. determine what the average current is over the time it takes to discharge and you have a good guess.

you can do it to the entire pack at once if you had left it together.

999zip999 · Mar 2, 2013

yes lighting in a box.

dutchlincoln · Mar 3, 2013

comes to mind: what would be the correct voltage to charge these packs?
The charger i got with it, gives 58.4 volts.
When i calculate 16S, makes 16 times 4.2 volts, getting a total of 67.2 volts, or better said: 8.8 volts too low?
Currently, they seem to get only (58.4/16) 3.65 volts each.
Now, that is the working voltage, and goor for LiFePo4, but not for A123 lipo i guess?

Anyone can confirm this?

dnmun · Mar 3, 2013

these are A123 cells as i recall so they are fully charged at 3.65V. to test capacity you would charge it up to 3.65V so it is fully charged and discharge it to 2.1V which is fully discharged.

dutchlincoln · Mar 3, 2013

Ah, ok. It can't be that then.

2.1v is pitty, yesterday i charged and discharged 2 cells each to 3 volts, and it gave me 15Ah.
This assumes they are correct then.

By the way: my wife has the same package in her scooter, and it's loosing capacity as well.
Don't ask: same victpower...

agniusm · Mar 3, 2013

It might be loosing capacity because of only one faulty cell. Get them all redone before its not to late. Get them disassembled and cleaned. Do a capacity test. (I have done mine 3.65 charged and then discharged to 2.0V, went by the spec). All my cells returned 19.6 on average. Its time consuming but this way you could find faulty cells and repair your packs to perform as they should. Those soldered connection are bad anyway because of aluminium tabs on the cell and it is a matter of time before they fail.
They are to costly not to take good care of them. Doctorbass was preparing hes cells perhaps for a few months before putting them in to a battery pack: measuring IR, capacity, self discharge etc.

dutchlincoln · Mar 3, 2013

okay, but disassembling isn't a easy job....
Is is possible on first hand, to charge each 2P section,and then discharge the section, in order to determine wich 2P pack is faulty?

Are those soldered tabs really that bad in time?

When i disassemble the pack, i'm afraid i will damage some tabs so severe, that they may become unusable...

Any idea where i can get these cells best?

agniusm · Mar 3, 2013

Who said that building batteries is easy?

Take your time and work through it. It won't happen over night. Its up to you in the end what to do with you pack.

dnmun · Mar 3, 2013

if some of the cells have started puffing, i would expect the other cells to also puff up.

the previous owner may have over discharged the pack to 0V and damaged it so it now has puffed up. so all the others may be in the same situation.

but you can test capacity while the pack is still assembled or use a voltmeter as the ammeter as i said.

cwah · Jul 11, 2013

did you decide on OSN or agnisium pack at the end?

repairing A123 victpower package, anyone?

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