VICTPOWER A123 Quality

[magudaman]

So I wanted to pick up some A123 before they dry up or disappear, plus I am hoping to do a larger pack for my bike so I can do some serious range. My Ebay source dried up that had the A123 20ah cells that I tested so now I am looking back toward china.

VICTPOWER can do $27 a cell shipped if not a bit cheaper for my quantity but I am hearing mixed reviews here and have been out of the loop for a while too.

They claim this is the full tab cell, never used and new.

So do I pull the trigger for my pack or not risk it. I plan on ordering an extra 4 cells to account for a couple bad ones if necessary.

 

[amberwolf]

Lots of discussion of their "quality", with varying results for different people at different times:

by post
http://www.endless-sphere.com/forums/search.php?keywords=+VICTPOWER&terms=all&author=&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search
by thread
http://www.endless-sphere.com/forums/search.php?keywords=+VICTPOWER&terms=all&author=&sc=1&sf=all&sk=t&sd=d&sr=topics&st=0&ch=300&t=0&submit=Search
by thread title only
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[mikebikerad]

Last batch I got was awful. The bms in the prebuilt packs cuts out a hair over 4 volts/cell. The solder joint on the main power connections to the packs were poor and came loose during light handling. It is hit and miss with cells, but I would read up about the prebuilt packs if that is what you are after. They told me they still have 60,000 good cells so no rush. Whole process was disappointing thus far.

 

[ambroseliao]

Why not buy from a trusted ES seller? $29 shipped.

http://endless-sphere.com/forums/viewtopic.php?f=31&t=46867

 

[999zip999]

Mikebikerad do you have any pics of the victpower pack do they solder the cell tabs ?

 

[izeman]

i bought from them during xmas time. communication was great, still they sold cells they didn't have.
cells arrived well packaged, but it was all really dirty in the inside of the pack. every cell packed in bubble wrap, but all from different batches. some short tabs, some with holes on negative side, some with long tabs, folded down to short tab size.
all cells between 18.500 and 19.900mAh discharge, but with a high IR of some 3mOhm.
i haven't used them. finished my pack today, and it will still take some time till the bike is ready to ride. so some more testing in the meantime.

 

[docnjoj]

I had dissed my Hyperion charger regarding R/int accuracy but lately it has been repeatable. It seems to show 7-8mohms Rint upon recharging about 10 ah back into the 20 ah pack. This is over the last 5 cycles. That would be great if actually true. The pack is 12 S of Victpower Amp20 cells purchased back in April 2012 full tab. Cells were in excellent condition when I got them. One out of 14 did not hold a charge well and was replaced about 1 month ago. I wish there was more aqccurate information, but I am quite happy with the Victpower/agniusm pack especially since the cell replacement was really easy.
otherDoc

 

[izeman]

Why do you consider 7mOhm good when it should be 1.5 max?
Mine are below 4mOhm for sure, as I could not measure more accurate. Highest load was 30A. Will see what CA-v3 says when connected for the whole 24s pack.

 

[miro13car]

ambroseliao,
can you tell us how do you like your A123?
Any tests you done?

 

[mikebikerad]

This is how all the packs were assembled and all of them had poor solder adhesion causing them to fall off like this. I got 18.6ah out of a 36volt 20ah before the BMS started cutting out.

 

[izeman]

that looks BAD. this seems the prove, that you can not SOLDER those cells. at least not with regular solder and a soldering iron. it may give some special solder that does work tough.

 

[docnjoj]

Why do you consider 7mOhm good when it should be 1.5 max?
Mine are below 4mOhm for sure, as I could not measure more accurate. Highest load was 30A. Will see what CA-v3 says when connected for the whole 24s pack.

Well that number is for the entire pack of 12 cells.
otherDoc

 

[docnjoj]

This is how all the packs were assembled and all of them had poor solder adhesion causing them to fall off like this. I got 18.6ah out of a 36volt 20ah before the BMS started cutting out.

That is one of the pictures I was talking about earlier in the thread about poor pack construction. I've never soldered aluminum successfully and apparently they (Victpower) are not doing it either. Ya gotta weld or better yet, clamp the connections.
otherDoc

 

[dnmun]

he needs to remove that ribbon of yellow double stick foam so we can see where it was soldered but that is the anode side of the pouch so it will have the aluminum electrode. we need to see if there is a nickel termination on that tab that can take solder.

 

[999zip999]

Seems like Victpower workmanship. I gald Victpower only resold my cells. Maybe never even touch them.

 

[mikebikerad]

That was a quick pic I snapped, I make little cuts with snips into the tab and scrape the hell out of it and I can always get a good solder connection. Not good enough for a full sized EV but for little 40 amp ebikes good enough. When the glue on the cell around the tab starts melting I back off with the heat

 

[izeman]

Why do you consider 7mOhm good when it should be 1.5 max?

Well that number is for the entire pack of 12 cells.
otherDoc

lol that IS good. how did you measure that? i connected the 24s pack to the ca-v3 today and it said 199mOhm for the pack. not great, but something i can live with. that is with all cables and connectors, and 2m of 10awg cable to the controller. just a quick check.
edit: my mistake. 199mOhm is NOT measured by the CA from the battery, but a user input value. damn

 

[docnjoj]

Why do you consider 7mOhm good when it should be 1.5 max?

Well that number is for the entire pack of 12 cells.
otherDoc

lol that IS good. how did you measure that? i connected the 24s pack to the ca-v3 today and it said 199mOhm for the pack. not great, but something i can live with. that is with all cables and connectors, and 2m of 10awg cable to the controller. just a quick check.

It is what the Hyperion says it is. Is it right? Who knows? At least I have some kind of repeatable baseline and can follow the pack as it ages. I honestly don't believe this has any absolute accuracy, but it could give some relative accuracy if the numbers change by a lot. Considering that agnuism's kits are rather well made there still is probabily more resistance in the circuits than in the battery itself. Again this is pure guesswork on my part.
otherDoc

 

[budabob07]

The title is pretty self-explanatory, but I would like to know if anyone has had any experience with the A123 AMP20 cells found here. They are pretty cheaply priced (22USD a cell) so has anyone used them? Also, I am unable to find any charge data on the cells, (A123's datasheet only lists discharge power). Can they be charged as fast as the 26650 A123's (4C). Thanks for your time.

 

[Hillhater]

Serch "Victpower" on this forum,..you will get a lot of reading matter.
bottom line is .... "Are you feeling lucky"

 

[neptronix]

Depends on your definition of legit.
Are rejected / meant to be recycled A123 cells your definition of legit?

 

[budabob07]

Alright thanks. Is there a source for reliable cells or not since A123 went bankrupt?

 

[neptronix]

A123 has never sold those big pouches direct to the public, so there's no legit source for new ones. What you see online is rejects from the factory for the most part.

The trick is to buy a crapton and test each cell.. weed out the bad ones. Kinda like dealing with hobbyking lipo, really.

 

[neptronix]

Browse around though, some people have had success after weeding out the cells that are junk, if you wanna go that route. Just search for 'a123' on this forum using the google box.

 

[circuit]

If you are desperate, buy fom osnpower. These are tested many times and are good enough.
Don't buy from victpower, they are junk. Even if these cells pass you inspection, they may die after a month. I had a pallet from them - its ridiculously bad.
I'd suggest to look at enerdel. They are offering cells at very good price lately. And these are as good as A123.