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a123rc 20Ah promotion

there was not debate, that guy just deliberately lied about how the cells would not take a charge even though his video showed that the cells he labeled dead were not dead.

he lied so he could get free cells from the chinese guy he bot them from.

to make matters worse he had that other guy who pretended to be an authority on batteries pretend to test them and that was somehow used as proof the cells were dead. that guy proved how ignorant he was by deliberately reversing polarity on the cells with his charger as though he would prove they were bad by destroying them. the effect of 60 years of domination of a free people by the soviet apparatchiks.

you do not know why cells puff up so you should not pretend that you do know, and that somehow your comments should be used by the guy asking advice as the basis for his decisions. that is just wrong to deliberately mislead him when he does not know any more than you about batteries.
 
What kind of discharge rate can these do? could a simple 14S1P arrangement handle 50ish amps continuous? if not then LiPo is the clear winner in that department! If they can, it seems these would be an ideal setup for simplicity of wiring and charging! Add a BMS and you got a simple setup for cheap!
 
If they are actually A123 pouch cells, then there are a number of threads that show the actual discharge capabilities, including some of the threads where people like Cell_man were working out mounting methods, and where people like Liveforphysics were doing discharge testing and melting FETs off of solid copper busbars. ;)
 
If they are actually A123 pouch cells
Click to expand...

That's all i'm saying. In the end if there was a good supply of the genuine thing for cheap, a lot more people would be buying them. Frankly, if this source exists, then why don't more of the community know? I was under the impression keeping up with the a123 test threads that a steady good cheap supplier had potentially been found, but only recently, and that the last good batch of a123 pouches that were sort of around for a time came from cellman. If there is a new steady supply of the 20ah a123 pouches that has been verified by us as having the proper amp hour and c rating, then the word should be more out there.

there was not debate, that guy just deliberately lied about how the cells would not take a charge even though his video showed that the cells he labeled dead were not dead.

he lied so he could get free cells from the chinese guy he bot them from.

to make matters worse he had that other guy who pretended to be an authority on batteries pretend to test them and that was somehow used as proof the cells were dead. that guy proved how ignorant he was by deliberately reversing polarity on the cells with his charger as though he would prove they were bad by destroying them. the effect of 60 years of domination of a free people by the soviet apparatchiks.
Click to expand...

hey friend; you sound aggressive and confrontational. In fact, all of your posts over this a123 issue even in the other thread are aggressive and have the tone of someone who is absolutely sure they know best. Is there any proof at all that you do? I can man up and take down inappropriate comments, but I doubt you will.

you do not know why cells puff up so you should not pretend that you do know, and that somehow your comments should be used by the guy asking advice as the basis for his decisions. that is just wrong to deliberately mislead him when he does not know any more than you about batteries
Click to expand...

why do lipo cells puff my friend? I'm pretty sure i do know, but maybe I'm wrong! It would be the second time today :)
 
OK, well whether these are legit or not it's obviously not something a noob like myself is going to be able to discern from behind my screen. Outside of building my own a123 pack from power tool packs, what is my best alternative? I just want the battery that will provide me with peace of mind (probably not LiPo) and ease of use. 48V and somewhere between 10 and 20ah.
 
IanJThor said:
OK, well whether these are legit or not it's obviously not something a noob like myself is going to be able to discern from behind my screen. Outside of building my own a123 pack from power tool packs, what is my best alternative? I just want the battery that will provide me with peace of mind (probably not LiPo) and ease of use. 48V and somewhere between 10 and 20ah.
Click to expand...

cell_man is well-known here, and will build you a custom pack out of a123 M1 cells.

http://www.endless-sphere.com/forums/viewtopic.php?f=31&t=19717
 
Thanks JD (Oatnet)


This is not directed at you JD - I've actually got lots of A123 20Ah pouch cells in stock and they test out to about 20Ah, not mid 18Ah. These cells weigh in at 496g, they are a little heavier than the previous batch I had which were about 30g lighter. They also have higher and more consistent capacity. I don't supply loose cells, only built packs. Every cell is checked to ensure low self discharge and the pack is discharge tested to ensure good capacity which is always in the region of 20Ah. They are not the same batch that lots are now selling recently and in some cases at very low cost.

I'm working on an interconnecting PCB to make make the assembly better and easier too. I haven't pushed these cells much as I want to get that arranged first.

After I had bought lots of these 20Ah cells it seems like a large quantity of 20Ah cells have entered the market. They look nice, have full tabs, but do not perform so well. I could buy these at a very good price, but to be honest I would not have confidence in their long term performance, plus I already have too many as it is. The low price is almost too good to be true. While a reduced capacity is not necessarily so bad, it could also be a sign that the cell is not in a good state of health and other aspects of the performance could also below par. It is my opinion and have been told by others these cheap cells were rejects and were meant to be recycled, but didn't make it there. When selling them they'll cover their backs by stating a low capacity, so at least they perform as stated, at least initially. The cells I have came from assembled packs and everything points towards A grade cells.

Much of the rating of A123 cells is down to self discharge. B grade does not mean crap, it does not mean lower C rate, it doesn't even mean less capacity, it could just be a slightly higher rate of self discharge than the limits. There are also C-grade, rejects ect.

If you want a built pack that has been tested and only built from good cells, give me shout. If you want to build it yourself and chance your arm on some loose cells from 1 of the box shifters over here in China, or the agent of a box shifter that's never even seen the cells, make sure you get a few extra and start studying how you are gonna assemble them into a pack :)
 
I only have 20Ah A123 pouch cells. As far as I can tell the 15Ah cells i previously had were not a production cell and they are no longer produced. A 12S 20Ah pack is no problem.
 
cellman,
I must say I value your opinion since you tested and sold more than 100 of 20Ah cells,
how thick is A123 20Ah cell?
Less or more than 7mm.
Some vendors says 6.8mm, also you say your cells are heaver than first batches, any change in thickness?
 
You are quite right, the previous batch I had in 2010 were roughly 6.8mm thick, weight was approx 468g. The cells I have now are 7.25mm when stacked up and total is divided by number of cells, weight is about 496g if I remember correctly, just very slightly under 500g. I sold A LOT more than 100 A123 20Ah cells, have a whole lot more than 100 now... :)

I haven't gone through all the cells I have now and checked those details but that is what I have noticed so far. As I said, I am seeing good capacity and low self discharge. I haven't yet hit the cells with really high loads but the simple tests I did with moderate loads suggest similar low internal resistance as previous cells.
 
Cell man,

Looking for a123 48V pack, would you please PM me a quote for the 20ah(or post here I don't care)?

I've never had to deal with anything but lead acid and I would like to keep it simple. The build I'm doing is for a week long trip to burning man so I would like it to be simple enough that I wouldn't have to worry about a friend doing it in my absence. (or me doing it in an "altered" state). Would this pack be the best option for me?

Thanks
 
I have bought a batch of those cells, see also this thread on diyelectriccar:

http://www.diyelectriccar.com/forums/showthread.php/a123rc-test-66700.html

However, if somebody is willing to tell me how to test the C rates of those cells, please tell me and I will post the results. I would also agree on sending one cell to somebody for free if that person would test it and post the results.
 
the C rates will be in line with A123's published estimates. if these were binned from normal production you would expect they were binnned based on the estimated internal resistance at the end of test. i doubt if these cells were rejects, but instead are part of the lots that A123 built in 2009 and 2010 for the chevy volt in the prototype run, and then did not get the contract.

there are others where the tabs have been cut off. those could have come from the dissassembly of packs that were built for GM to test, and to recycle them they just cut them out of the packs with a knife and sent them to be recycled. just a guess.

but if they have the A123 logo, then they are made by A123.
 
How hard and at what cost can i expect to replace a 24v 18ah pack with 24 ish volts of theses 20 amp pouches in the UK?
 
cell_man said:
I'm working on an interconnecting PCB to make make the assembly better and easier too. I haven't pushed these cells much as I want to get that arranged first.
Click to expand...

Cell Man, is it not possible to spot weld the tabs together of these prismatic cells?
 
Spot welding them together directly is not possible with the equipment I have available. I spot weld other material to the tabs and then solder these prepared tabs together into series and parallel strings.
 
Degull said:
Cell Man, is it not possible to spot weld the tabs together of these prismatic cells?
Click to expand...

The tabs themselves do not have enough resistance to weld with a conventional spot-welder. Here is how I did it:

Spot-Welding a123 Prisimatic tabs

-JD
 
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