Victpower battery pack after 1 year

[cwah]

Wow, 50% failure rate from the original US cells... that's crazy bad. Thanks for the advice I was considering Victpower again. Apparently the current cells from Korea where supposed to be trashed, they cut the tab so people couldn't use the cells. But Victpower bought them 1USD/cell and welded tabs on it so it can be used again :lol:

But I've seen you're not using BMS on your pack? Why don't you use one? Unless you are monitoring your pack at the cell level, you might have over-discharged few weak cells without knowing.

 

[arkmundi]

But I've seen you're not using BMS on your pack? Why don't you use one? Unless you are monitoring your pack at the cell level, you might have over-discharged few weak cells without knowing.

I covered the topic of to BMS or not to BMS in other threads - see my Saga thread. I've altered my stategy to include a balance charger and celllogs. I'll do my best to keep my pack healthy until the last of my stash of cells is exhausted, then its bye-bye pack and begin the whole round again.

 

[cwah]

I tried to use celllog on my previous lipo pack as monitoring tool. But it was a lot of hassle to always have to stay close to the pack while charging. And same during cycling, have to stop to check cells status is annoying.

 

[Ishikawa]

But I've seen you're not using BMS on your pack? Why don't you use one? Unless you are monitoring your pack at the cell level, you might have over-discharged few weak cells without knowing.

I covered the topic of to BMS or not to BMS in other threads - see my Saga thread. I've altered my stategy to include a balance charger and celllogs. I'll do my best to keep my pack healthy until the last of my stash of cells is exhausted, then its bye-bye pack and begin the whole round again.

If you over discharge, you can kill any battery no mater what kind of chemistry or where it's made, who made it. I am surprised arkmundi did not kill more cells. That shows a123 cells are well made IMO. I am using a123 pack (16s) for few months now without BMS. I do not see any problem at all. I check cell voltage before and after the charge also before and after the ride as well. No fancy charger or Cellogs. And so far I did not need any balancing either.

 

[etriker]

But I've seen you're not using BMS on your pack? Why don't you use one? Unless you are monitoring your pack at the cell level, you might have over-discharged few weak cells without knowing.

I covered the topic of to BMS or not to BMS in other threads - see my Saga thread. I've altered my stategy to include a balance charger and celllogs. I'll do my best to keep my pack healthy until the last of my stash of cells is exhausted, then its bye-bye pack and begin the whole round again.

When you do testing of cells in a homemade pack adding a bms would make for more testing because you have to test and monitor the bms too.

Without close monitoring of the bms you will not know if it was the bms that killed the cells if they go bad during your testing of the pack ?

Get some A123m1 cells and put together a small pack. A small pack of these cells can still deliver punch.

Learn how to monitor and keep the small pack alive with a good balance charger and cell logs and when you can do that go for larger packs that cost more $ ?

That is how I learned.

 

[etriker]

I tried to use celllog on my previous lipo pack as monitoring tool. But it was a lot of hassle to always have to stay close to the pack while charging. And same during cycling, have to stop to check cells status is annoying.

A bunch of SLA mounted low would be a good choice for you ?

 

[cwah]

If you over discharge, you can kill any battery no mater what kind of chemistry or where it's made, who made it. I am surprised arkmundi did not kill more cells. That shows a123 cells are well made IMO. I am using a123 pack (16s) for few months now without BMS. I do not see any problem at all. I check cell voltage before and after the charge also before and after the ride as well. No fancy charger or Cellogs. And so far I did not need any balancing either.

From where did you source your A123?

 

[cwah]

[

When you do testing of cells in a homemade pack adding a bms would make for more testing because you have to test and monitor the bms too.

Without close monitoring of the bms you will not know if it was the bms that killed the cells if they go bad during your testing of the pack ?

Get some A123m1 cells and put together a small pack. A small pack of these cells can still deliver punch.

Learn how to monitor and keep the small pack alive with a good balance charger and cell logs and when you can do that go for larger packs that cost more $ ?

That is how I learned.

I used to use balance charger to charge my 20s pack with 2 hyperion 1420i in series. It was a hassle during daily basis and it's a setup like a tank with 2 power supplies and 2 chargers.

Issue with cell log is that it discharge cells un-evenly. Did you manage to mod your celllog for even discharge across all cells?

 

[etriker]

No. I unhook it from the pack after the ride is over.

The battery pack is also disconnected from the controller.

Nothing is hooked to the cells when the ride is over.

The cells are only connected when charging or when riding.

That way the cell logs can not discharge the pack and if the voltage changes on the cells while sitting not used you know it is not the bms or cell logs causing the voltage change.

 

[Cephalotus]

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:...

What you got is a bomb not a battery. I have never seen something like that before (that was not intended to explode). It's pure luck maybe a quite forgiving cell chemistry that nothing terrible happened so far.

I amazed that you believe that holding a butane torch at your bomb is a good idea and I'm even more amazed that you still consider to purchased from that factory.

700 US$ is significant money, but it's little money if used wisely for education and learning. Losing your house or your eyesight will be more expensive.

In the automotive sector they refuse poach cells that have a slightly scratched corner (I talk about the sealing, not the cell) and tolerances in cell size and positioning are below 0.5mm. EVERY cell in your package has been mechanically abused way beyond design and because of the cheap price most likely every cell has been off spec. from the beginning.

You are playing with a bomb, not with a battery.

 

[Ishikawa]

If you over discharge, you can kill any battery no mater what kind of chemistry or where it's made, who made it. I am surprised arkmundi did not kill more cells. That shows a123 cells are well made IMO. I am using a123 pack (16s) for few months now without BMS. I do not see any problem at all. I check cell voltage before and after the charge also before and after the ride as well. No fancy charger or Cellogs. And so far I did not need any balancing either.

From where did you source your A123?

I bought cells and connector kits from OSN.

 

[999zip999]

You can't use an open flame. We did talk about a 80 watt solder iron. Lot's of junk in that pack ?

 

[wb9k]

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:...

What you got is a bomb not a battery. I have never seen something like that before (that was not intended to explode). It's pure luck maybe a quite forgiving cell chemistry that nothing terrible happened so far.

I amazed that you believe that holding a butane torch at your bomb is a good idea and I'm even more amazed that you still consider to purchased from that factory.

700 US$ is significant money, but it's little money if used wisely for education and learning. Losing your house or your eyesight will be more expensive.

In the automotive sector they refuse poach cells that have a slightly scratched corner (I talk about the sealing, not the cell) and tolerances in cell size and positioning are below 0.5mm. EVERY cell in your package has been mechanically abused way beyond design and because of the cheap price most likely every cell has been off spec. from the beginning.

You are playing with a bomb, not with a battery.

These packs are not the paragon of safety, but it takes some real effort to get an A123 cell to explode, and I'm not sure it can be done at all with a pouch cell. You can get the cylindricals to do it every now and again if you overcharge with huge current.

This thread seems to have gone hyperbolic.....

 

[eva-michael]

It would better make a hard outside packing for pouch cells pack. Or it's easy to get deformed and cause problem.
I don't think this is a good business for most of the people. In China, we call them diassembled cells. Each pcs has different quality.
It will require a lot of care to make pack by these cells.
Don't usre flammable matterial, it will be a big mistake,

 

[Spacey]

Well just pulled 19.5Ah out of my pack, had one pack fail out of 10. Seems the cell had been punctured, you have to fix that positive lead that has been 'soldered' ahem onto the positive lead....copper to aluminium was never going to work.

Just drill 6 small holes in the last cell positive tab....weave some 16 awg rc wire through it...solder blob the lot and crimp. Seems to work just fine.

 

[Spacey]

It would better make a hard outside packing for pouch cells pack. Or it's easy to get deformed and cause problem.
I don't think this is a good business for most of the people. In China, we call them diassembled cells. Each pcs has different quality.
It will require a lot of care to make pack by these cells.
Don't usre flammable matterial, it will be a big mistake,

Buying your mess of a battery was big mistake for me a few years ago.

 

[Cephalotus]

These packs are not the paragon of safety, but it takes some real effort to get an A123 cell to explode, and I'm not sure it can be done at all with a pouch cell. You can get the cylindricals to do it every now and again if you overcharge with huge current.

This thread seems to have gone hyperbolic.....

the chemistry is what propably saved him so far. Poach cells have never been intended to be built in packs like that warpped with some tape and heavily abused. They are designed to be babied, protected from vibration, high pressure, temperature outside a certain range, etc. pp. they are usually also not designed to be soldered...

Look how car manufacturers built battery packs. They use a crah save containment, thermal management, vibration reduction systems, special cell conectors and they protect the cells from even the slightest mechanical stress. Even 0.5mm bending is not accepted. If you look at that battery pack everything has been done to destroy these cells that have been faulty from the beginning. And now he wants to use his butane torch to solder the tabs...

Maybe people will drive around their gas in an open pot within the car while smoking...

Wouldn't it be wiser to use cylindrical cells if you can't make a suitable battery system for poach cells that have ultra high requirements for packaging?

Suitable would be a hard outer case with crash/impact protection, a plastic frame with super tight tolerances for every single cell, anti vibration packaging material, cell connection as suggested by manufacturer, active thermal management system, high quality battery management AND battery monitoring system...

 

[cwah]

the chemistry is what propably saved him so far. Poach cells have never been intended to be built in packs like that warpped with some tape and heavily abused. They are designed to be babied, protected from vibration, high pressure, temperature outside a certain range, etc. pp. they are usually also not designed to be soldered...

Look how car manufacturers built battery packs. They use a crah save containment, thermal management, vibration reduction systems, special cell conectors and they protect the cells from even the slightest mechanical stress. Even 0.5mm bending is not accepted. If you look at that battery pack everything has been done to destroy these cells that have been faulty from the beginning. And now he wants to use his butane torch to solder the tabs...

Maybe people will drive around their gas in an open pot within the car while smoking...

Wouldn't it be wiser to use cylindrical cells if you can't make a suitable battery system for poach cells that have ultra high requirements for packaging?

Suitable would be a hard outer case with crash/impact protection, a plastic frame with super tight tolerances for every single cell, anti vibration packaging material, cell connection as suggested by manufacturer, active thermal management system, high quality battery management AND battery monitoring system...

The butane torch was NOT used to solder, it was used to DESOLDER the cells. Goal was to generate enough heat fast enough to desolder the tab. But experiment shown that heat transfer was too high and it was burning the cells at the same time. So it's better not to desolder them.

The pack was protected with:
- An initial layer of compression tape
- A second layer of 5 mm anti-vibration foam
- It was inside an 8mm polycarbonate box
- Corner were protected with steel material
- Box was inside multiple layer food wrap to protect from rain and make it waterproof
- All was inside another bag and tapped again

To damage the cells either from vibration or heat, it would have been REALLY difficult. The pack was really tight and well protected. Even fire would have been contained with such a box. The only reason I discovered this failure was because I decided to do a sanity check on my pack after winter. Otherwise pack could still be used, the only thing detected was the much lower range (I thought it was because of winter)

 

[999zip999]

You turn the pack upside down and heat with a big solder iron the solder will ball and hold togethere. When the solder is molted hot, hold the pack with two hands and snap the wet solder on a peice of plywood. It will get hot but most likely not caught fire. Do this on the open cleared driveway away from the car and gasoline. That's if you must take it apart. Start by throwing then sucking the solder off, Then get a sharpen metal rod in a small wood handle so you can hold the pick and heat the mainly cleaned tabs with the iron and pick the tab up from the pcb. Then cut the pcb or slide it up when very hot melted so you don't rip the tab. you don't need it to smoke. Not that hot.
NOW I didn't you to or how do do it. As these cells are live and you can start somehing that you can't stop. It's not a pouch of tang that you put a straw in for a drink. It has a LOT of stored energy. GOT it. Maybe a ceramic pick. Big cells hold lots of juice. Not a toy.
I can do it as I'm a jewler, that cast silver and make different karat gold. Also weld and install rod iron fences. Molten metal is hot and a fire hazard.

Danger ! May cause FIRE. Not easy to put out. The energy is inside the cell and you can't see it.

Now this is how I would do it. I don't sugest anybody do or try this. A123's can't be solder.

 

[Ishikawa]

You do not gain anything by desolder the tubs. I would guess that you want to take the cells out and use it with another connector kit. But it is very tedious job to start with and it is almost impossible to eliminate solder from tubs which make the bending or straighten of the tub difficult (tubs will be thicker). Not only that, the heat will cause further damage to the pouch and seal, will add more problem to already somewhat compromised cells.

 

[eva-michael]

It would better make a hard outside packing for pouch cells pack. Or it's easy to get deformed and cause problem.
I don't think this is a good business for most of the people. In China, we call them diassembled cells. Each pcs has different quality.
It will require a lot of care to make pack by these cells.
Don't usre flammable matterial, it will be a big mistake,

Buying your mess of a battery was big mistake for me a few years ago.

Here already a review. They are headway cells with EVA resistor bleeding BMS. No any tricky........
http://endless-sphere.com/forums/viewtopic.php?f=4&t=30923&p=729786&hilit=evassemble+pack#p729786
I think we should solve the hatred and pls pm me and I will see how can we finish this. Maybe we can supply you by low low cost or any other ways.
We may have some inadequate document explanation few years ago which may cause misunderstanding. And we have worked with few ES menbers to work out some adequate instructions which is easy to comprehend. Here again, thanks for ES menbers' assistance.

Sincerely
Michael

 

[miro13car]

I am with Ishikava
I run A123 20Ah 12S for all summer , over 100 charges with no BMS , just using battery doctors.
I simply turn discharge on BDoctors to 3.6V and turn on charger, but I watch for the end of charge and disconnect charger immediately.
No worry about balancing, after 2-4km of ride all cells are balanced perfectly.
That's my observations.

 

[yokneamcity]

A year ago, I bought a pack of these cells for my scooter from OSN-power (16S-3P)
After half a year of operation began problemmy.
First two cells were swollen. I replaced them. Then swelled another cell.
I also replaced the damaged cell.
After that, I took apart the battery for a new project, Battery for Vectrix scooter.
I bought another 36 cells to complete the project. 42S-2P
Yesterday, I finished making the battery. Check internal resistance and voltage of all cells. Charged the battery and did test drive on Vectrix scooter.
The next day, I again found the inflated cell.
I always use BMS and the cells were never overcharged and never overdischarged.
On the old and the new scooter, I use different BMS.
I spent a lot of money these cells, time and effort.(82 cells)
I am very upset.

 

[cwah]

Noooooooo.... :x

I was about to purchase 25 cells from OSN thinking they were muuuuch betttter.. And now I'm NOT GOING TO BUY ANYMORE from what you saaaiiiiid

How can I buy from anyone these cells now...

 

[999zip999]

I'm just guessing but the cells are from a recall 2yrs. a more ago and where sent to China for recycle and some of the best ones were sold early. The days of 18.50 usd cells that work is ?