a123rc 20Ah promotion

spkpn

spkpn

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Oct 4, 2011
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FIY

there is a new promotion sell out of 10000 a123 20Ah cells on a123rc. At a price of 37$ per cell (shipping included afaik).

http://www.a123rc.com/goods-468-Exci...TIC+CELLS.html

My experience with this vendor is good so far, see also

https://docs.google.com/spreadsheet/...GB&pli=1#gid=0

not yet tested all cells tough and cant say anything about whether or not the cells meet their specs concerning power density.

rgds

PS: there are also 100 cells of 15Ah @ 30$
 
rojitor said:
Pretty good discount, maybe i rushed too much ordering lipo ;)
Click to expand...


You can always buy more. :)

As for the batteries, i would buy a couple more than what you need just incase some arrive dead.

As for me, i am done dealing with unverifed batteries. I am not saying these are fake, but i am also not saying these are legit A123 batteries

Let us know how the cells go.
 
3.65V20AH is 73 WH. The cell weight 480g.

So it's 152.08 wh/kg.
Lipo are around 140wh/kg.
So it's higher energy density than lipo.

Lipo cost around 0.48$/wh (Zippy).
And this A123 is at 0.82$/wh (at 59.99USD)

But now with promotion it's now at 0.5$/wh. Almost the same price as lipo.

Seems to worth it. Is it difficult to create a pack from that? If I want a 60V pack, would that be easy to do?
 
cwah said:
3.65V20AH is 73 WH. The cell weight 480g.

So it's 152.08 wh/kg.
Lipo are around 140wh/kg.
So it's higher energy density than lipo.

Lipo are around 2Wh/USD (Zippy).
And this A123 is at 1.21wh/USD.

So these pack are slightly lighter than lipo but almost 2 times more expensive? Worth it?
Click to expand...

This is wrong the A123 20Ah cells are 3.3V nominal. They are rated at 66Wh and spec'd at 480g to 496g. That comes to 133 to 137 Wh/kg. A single turnigy 20C 5Ah is about 162Wh/kg (source - hobbyking site). These are all based on spec sheets not my real world numbers
 
Thanks Nuts&Volt.

I was comparing to my zippy flightmax:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=16227

These one are at 140wh/kg.


Which lipo have the best energy density at the lowest price in hobby king? I'm looking for high voltage + high AH pack in order to have the minimum number of lipo to connect. If you can provide the page link that would be great :lol:
 
Yea I would be pretty interested in an easy solution to use these cells. From what I understand they are
one of the better safer solutions.
 
I got this email from Victpower over the holiday. I have not responded as I currently don't have a project waiting for these cells. I think they are the same cells that are currently being tested on EVTV and are putting out an average of 18.5 Ahr. In any event seems like a decent price.




RE: Inquiry from LIION battery cell A123 20AH cells Rechargeable
This message was sent to you only. Don't miss this great business opportunity
Registered Location and Message Origin: CHINA (MAINLAND) Message IP: 123.125.21.*
Dear Martin,

Hello Martin,

Happy New Year. Long time no reply from u.

In order to Celebrating the New Year, the A123 20ah price have a discount ,now the unit price is US$24.98.

Any need can contact me.

Thanks

Cherry


Ms. ziying yang

Company: Shenzhen Victpower Technology Co., Ltd.
Country/Region: China (Mainland)
Address: 1-2F., Building C, No.28, Xinmuxinyuan Industrial Park,Pinghu Town,Longgang district,Shenzhen city,China.
TEL: 86-0755-89635916
FAX: 86-0755-89635636
Click to expand...
 
I'm getting ready to do my first build, for all intensive purposes it is basically an ebike conversion (hub). I'm planning a 48 volt system and 10 to 15 ah is what I wanted to shoot for but only because I thought 20 would be too expensive. I like the idea of using a123's because it takes a lot of the pressure off of me burning my place down. Also I won't have to worry as much about someone else using my system. From what I understand I just have to be primarily concerned with not over discharging a123's .

Couple questions:
Are these a good starting point for building my own pack and how would you guys go about building a 48v 20ah pack from these?

How would the cost savings compare to buying a pre-made pack/Is it worth it in your opinion?

And is building a pack an undertaking I should be able to do as a noob. I am very handy, mech engineering student, work in a machine shop etc., but I've never worked with batteries before.

Thanks for the help!

Ian.
 
connecting the tabs and soldering the sense wire for the BMS is the biggy. there are a lot of different techniques written up on various threads. i think cell man makes metal clamps for the junction that get tightened up with a screw.

the advantage of large cells like these 20Ah pouches is that you do not have to connect several in parallel to get that amount of capacity, which simplifies the connections.

there are several used packs for sale on the sphere now too.
 
cwah said:
3.65V20AH is 73 WH. The cell weight 480g.

So it's 152.08 wh/kg.
Lipo are around 140wh/kg.
So it's higher energy density than lipo.

Lipo cost around 0.48$/wh (Zippy).
And this A123 is at 0.82$/wh (at 59.99USD)

But now with promotion it's now at 0.5$/wh. Almost the same price as lipo.

Seems to worth it. Is it difficult to create a pack from that? If I want a 60V pack, would that be easy to do?
Click to expand...

If you go for turnigy nanotech which is suppose to be better than the regular turnigy and considerably better than the zippy, the price per wh can be pretty close to these A123 and you get to customize the pack.

here is my calculation:
If you buy Turnigy nanotech 10s5ah right now in USA warehouse, it come out to be like 102 + 10-15 bucks shipping depending on how much you buy.

So say $120/(37*5) ~= $0.65/Wh which is pretty close to these A123.
$37/(3.3*20) ~= $0.56/Wh

Now IF the batteries are legit A123, then you will get really long life cycle. However, that is not guarantee, so I will rate it as similar charge/discharge cycle as the nanotech assuming you charge the nanotech correctly.
 
There are no legit brand new a123 pouches; the company never sold any in new form to the consumer market, If you are buying A123 pouch cells they are harvested from companies a123 has sold stock too. However that doesn't mean they don't work, only that there are a couple different sites and vendors selling these pouches now, and I would bet on luck being the highest quality control they have.
A couple of these vendors are getting favourable reviews, but don't depend on the label for your comfort, I would insist on a sample and then test it's capacity and C rate and such before investing a few hundred in these over the tried and true lipo from HK.
 
What's so special about the nano tech? It's not lighter than zippy. Maybe more lifecycle, higher C rate and lower resistance. But the most important is the weight isn't it?
 
cwah said:
What's so special about the nano tech? It's not lighter than zippy. Maybe more lifecycle, higher C rate and lower resistance. But the most important is the weight isn't it?
Click to expand...

"More cycles, higher C rate and lower resistance" - that's it.

What's most important is really dependant on what the packs are going to be used for. If lightness was the most important thing for batteries no one would be using LiFePO4 :p
 
One other factor is they reportedly puff less over time too due to the difference in chemical composition.
 
whatta buncha malarkey.

these cells are labeled A123, they are A123. nobody protects their brand like they do.

these cells labeled "made in US" were made at the A123 plant in livonia. JD posted up a video from the plant on another thread about these cells.

you don't even know why cells puff up so how can you makes such claims. this is all just idiotic chattering.
 
sure friend.

enjoy your batteries :)

this is the thread he was talking about for all those interested in these batteries; there is heated debate there too for anyone who wants to go read it. In the end i don't think my advice of testing first was out to lunch, and you can either believe the cells are real or not as far as i can tell from the other threads discussion.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=26072
 
Andje said:
There are no legit a123 pouches; the company never sold any in new form to the market, If you are buying A123 pouch cells they are fakes made in China, that's a fact.
Click to expand...

a123 supplies cells to Mavizen to sell to consumers, so they do get to the market in 'new form'. I agree that the other cells are not 'legitimate' - instead they are B-stock, overstock, used for testing, etc etc etc, but I disagree with your assertion that they are 'fakes'. If China makes fakes with this level of IR, able to supply 20c+, able to supply 19-21ah and weigh the same as "genuine" a123 cells, I'd say sell me all the "fakes" like that you got. :mrgreen:

I've got a lot of experience on these cells, and while there are scams out there, the "illegitmate" ones I have are not fakes. Here is the method I use to join cells:

Spot-Welding a123 Prisimatic tabs

-JD
 
ill take the word out. i agree, it's inappropriate.
 
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