Victpower battery pack after 1 year

[Ishikawa]

It is depend on how much space you have on your bike for the battery pack. If you have enough space, fix it as dunum suggest. Cut the bad cells out and stick something in the place, foam,plastic or maybe 1/4" plywood etc. And buy 4 cells and connector kit to make 4s pack, put it in series to old pack. Now you have 20s with the size of 24s. I think this is the least amount job and cost.

If you buy OSN connector kit, it is modular. I bought 2 8S kit but I made a 12s and 4s instead. you can add more cell in the future if you needed.

Also their short tub cells, the tubs are too short to use with their kit, but they offer to cut the top of the pouch to make the tub longer. But I told them not to cut the pouch. I made thin copper strips to bridge the tubs.

 

[999zip999]

Never cut pouch under the taps.

 

[agniusm]

I wander why the tabs should break when desoldered? At least copper one should be fine.

 

[dnmun]

it is not that the tabs break when unsoldering. i have found it impossible to remove all the solder and get the tab free in the slot without a lot of heat and even then there seems to always be a little bit of solder in the slot.

therefore in order to get the tabs free you have stand up the tab in the slot while molten, for both tabs, and then slide it out, but usually it hangs on one side and the side that is unsoldered comes free but the side still stuck gets twisted. the aluminum tab develops stress cracks and tears.

if you want to go to high voltage again and you only have a 16S then add another 8S pack in series to go to 24S. but 16S@20Ah is not that bad, imo. if the cells you add are identical to these then you could use a 24S BMS for it. or just add 4S under your old 20S BMS. but add them on the end by themselves with a clamping type connector.

the problem is that the A123 pouches you get cannot be soldered.

 

[cwah]

Thanks for all your answers guys. I'm currently located in France, Paris.

So what I have to do now is to :
- Cut the bad cells and fill the gap with foam
- Purchase a 4S kit from OSN to get my 20s back. Or maybe an 8s would be more appropriate? I can see more cells having problem in the future :lol:
- Buy 10 additional cells for future issues
- Buy a new BMS because mine isn't working?

And my battery will be saved?

 

[dnmun]

there will be no gap because the other pouches will swell up and fill the space or you can cut the pcb down in size too.

add the new cells on the end and rewire the sense wire plug. the new cells can be installed using the clamp type system that agnius designed or the OSN type. there are other tricks too like the cotter key clamp.

you don't have to use all the spaces in the clamp kit, just enuff to get back to the size you wanted. but you wanna have a pouches that act like the other pouches when charging and discharging which kinda means going back to them and asking for more of these.

maybe show them what happened (especially the ones with the aluminum corroded inside the mylar) and see if they will sell you some more for 1/2 price because these were defective.

 

[izeman]

Or maybe an 8s would be more appropriate? I can see more cells having problem in the future :lol:

you can order as big as a kit you want and remove as many segments as you wish. those kits are made of single segments plugged together. so to make a 7s out of an 8s kit, you just remove on segment. easy as that.

 

[cwah]

Ok sounds like a plan

Shall I get a new BMS or not? or is there any way to know if my BMS was working properly or what was the cause of failure?

No point to order new cells if they're going to die

 

[cwah]

Ok, finished my purchases. I'm ready to desolder some cells from my brompton. Just a try before I just cut them out

 

[izeman]

oh man. heavy tools. you're sure you want to repair a battery?
good luck with that stuff. why didn't you just buy a regular 80w soldering iron?

 

[dnmun]

all you needed was some scissors. you already had a soldering iron. i don't think you get it. you cannot solder to aluminum. the anode has an aluminum tab.

 

[cwah]

I know but I want to try to desolder first. If it doesn't work I'll cut them with scissor

 

[arkmundi]

I think I have basically few choices now:
1. Cheapest/Easiest: I can replace the bad cells directly in this pack:
2. Intermediate: I salvage all cells and replace it with a new kit from OSN/Agnisium and buy 6-8 additional
3. Most expensive: I buy a new battery from OSN power.

Go for option 2. You'll have to amp up your equipment & experience, but you'll be rewarded with the ability to manage & repair your own pack. If Agnisium is still manufacturing his kit, I'd go for that, but the OSN kit looks OK. As other threads have suggested, there seems consensus that Victpower may be played out as a source. I'd try to get replacement cells from Cellman first and then OSN. Also worth considering is option #3, with salvaged cells on hand for replacement to extend the life of the pack.

 

[999zip999]

Best is a 80w plus big fat iron. Open flame next the top of the battery ? Or did it gave a solder tip ? These are very very powerful cells and don't have an off button if shorted you can only put the cell in a metal bucket.

 

[arkmundi]

I posted a reply to anyone interested at viewtopic.php?f=14&t=51400. I feel for cwah, and anyone else here in ESland that have sourced A123 AMP20 cells from the grey market. I like many, knew it was a bit of a gamble and wagered anyway. Others may have not realized the risks and feel cheated. In all cases, we've made an investment worth protecting, for the longevity of our battery packs. The above thread is about finding a suitable replacement for individual cells in our A123 AMP20 packs. Its an open question. I suggested the Tenergy 20ah prismatic cell. Le'ts try to make some collective wisdom together on the question. Best.

 

[999zip999]

Victpower has a history of bad build packs. The round cell packs are always a gamble. With the A123 they use sold everything they could get their hands on. The price was right. But they sold a lot of good cells. I just think they could care less good or bad. It was just the money to Victpower.

 

[cwah]

I tried to desolder with butane torch lol. But it really gets the cell too hot and all the plastic around melted. I found it near to impossible to remove the cell:

I'm going to buy some spare cells somewhere. I need some advice, shall I buy for:
- 13.8USD/cell with Victpower again. Only the pack was bad but potentially the cells are ok? The cells are apparently made from Korea but don't have logo.
When they'll arrive, I can test all of them and directly claim money back for any not working cell.
http://www.aliexpress.com/item/A123-20Ah-Systems-Prismatic-Pouch-3-2V-AMP20M1HD-A/749139285.html

- 20 USD/cell from OSN. They have better reputation and have half tab cells. It would be grade B cells.
http://www.aliexpress.com/store/product/Promotion-Free-Shipping-100-new-original-short-tab-3-3V-20Ah-A123-LiFePO4-Prismatic-battery-cell/225525_1005328331.html


I know it looks like I repeat myself, but it's a huge amount of money and I'd like to spend as little as possible!!

 

[LSBW]

Obviously OP never heard of Russian saying "Я не настолько богат, чтобы покупать дешевые вещи", which roughly translates to:

"I am not rich enough to buy cheap things"

Well, live and learn. I don't know why you expected your battery pack worth $780, to be as good as cell_mans pack for $1500, but hopefully you learned your lesson.
I, too, spent shit load of money on Konion cells from doctorbass and learned my lesson.
My next bike will be built around A123 battery pack from cell_man.

 

[arkmundi]

Its just so painful to be seeing those pics and following this thread. Being one of those that sourced my cells from victpower and undergoing a certain degree of pain myself seeing cells go bad. Anyway, for what's it worth, I feel your pain. In retrospect, it was a really bad idea to use a torch on your pack to extract the cells, so just another lesson. Thanks for posting ... a road no one should try to follow. FYI, I'm in the process of looking for some drop in replacement for A123 AMP20 cells, sourced legitimately and with some warranty or guarantee. That's an open question.

 

[davec]

ark good luck with that
every email i've sent to a123 corporate or any employee has been ignored
cwah i feel sorry for you-- that pack is just gross

 

[lionschasing]

not necessarily so...
http://endless-sphere.com/forums/viewtopic.php?f=14&t=51400

ark good luck with that
every email i've sent to a123 corporate or any employee has been ignored
cwah i feel sorry for you-- that pack is just gross

 

[arkmundi]

So, cwah, how'd that turn out for ya'?

 

[cwah]

I'm still looking for reliable seller to buy A123 20AH cells. For now, OSN seems to be the only one with decent price and positive feedback from community..

So probably buy few cells from them..

 

[cwah]

Its just so painful to be seeing those pics and following this thread. Being one of those that sourced my cells from victpower and undergoing a certain degree of pain myself seeing cells go bad. Anyway, for what's it worth, I feel your pain. In retrospect, it was a really bad idea to use a torch on your pack to extract the cells, so just another lesson. Thanks for posting ... a road no one should try to follow. FYI, I'm in the process of looking for some drop in replacement for A123 AMP20 cells, sourced legitimately and with some warranty or guarantee. That's an open question.

How did your cells turned out bad? Was it all of them? or only a small percentage? And what cells did you purchase? Korean ones?

 

[arkmundi]

How did your cells turned out bad? Was it all of them? or only a small percentage? And what cells did you purchase? Korean ones?

I bought a total of 21 cells from Victpower, an original package of 14 and then split a package with another ES'er. I bought the additional 7 seeing my cells going bad and wanting to source additional cells before the marketplace for them went sour. All are with the "Made is USA" label, so not the Korean factory output.

I've had to replace 5 cells in my 12S pack, so getting close to a 50% failure rate. I have 4 cells left. You can see more at A123 AMP20 cell diagnostics. I'm in the process of implementing balance charging and putting in some celllogs to monitor the cells ongoing.

I will not buy anymore A123 AMP20 cells unless a factory window for factory seconds can be worked out. wb9k thinks that possible under new management from the Wanxiang Group. We'll see. But if I were, yes I'd get them from OSN. And NOT Victpower at this time.