# A123 Batteries from Dewalt



## ViolentBlue (Apr 19, 2008)

anyone know how many amps the Dewalt 36v battery packs are putting out?
at $100 a piece I'm wondering how economical building a battery pack for my vehicle out of them would be.
considering the cost of other lithium units, I'd hope I could get double the kwh for the same price.


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## MrCrabs (Mar 7, 2008)

Where are you finding $100 dewalt packs? just curious, because last time I looked, they were 150.
The dewalt pack simply contains 10 A123 cells, and here are the specs.
http://a123systems.textdriven.com/product/pdf/1/ANR26650M1_Datasheet_MARCH_2008.pdf

Nominal voltage 3.3 V and they store 2.3 Ah....
So if you wanted a 96 volt pack, with 45 Ah, you would need 20 strings in parallel of 3 packs in series... or 60 packs so $6000. Rough calc put them at $1.33/Wh which is more than other lithium batteries...however if you could reuse the BMS in the pack, it might be worth it.... if you didn't mind dealing with all the plastic casings


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## ViolentBlue (Apr 19, 2008)

on ebay you can find them for $100.
I had hoped they had more juice than that. too bad.


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## 3dplane (Feb 27, 2008)

Hi!
A couple of things to consider though! Look at the discharge curve(on the graph) It's almost flat.Wich means you can use almost all the juice out of it before it falls off without detrimental effect on cycle life.(if the claims are true)You get better use out of them for a given capacity compared to other chemistry. I'm not really sure what is the safe DOD on the other "popular" lithium chemisry but i'm pretty sure it's not as much as the A123.(you better be aware of your range though cause it looks like there is no sign of loosing performance before it's discharged).Then finally look at the discharge rating. In the example pack configuration above( 20 paralell strings) the continuous amps available would be 1400A,and the burst 2400A! (not like you would want to run your system like that but nice to know it's there if needed)
No surprise that's what powers killa cycle and I think white zombie too.
Barna.


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## Da_Fish (Apr 28, 2008)

3D my Ohms law is a little rusty so forgive me if I am wrong here. When you series the batts your voltage becomes additive but I dont think the AH rating or the amp output becomes additive....does it? If this was the case then the lith iron batts that are just hitting the market with 3.2 volts and 100A would be beyond phenominal!!


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## MrCrabs (Mar 7, 2008)

Your right about adding batteries in series. Voltage adds up, current stays the same.
However when you have batteries in parallel, voltage stays the same, and current adds up.
In my earlier post I mentioned having 20 parallel strings of 30 cells in series.


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## Cornelius (Sep 15, 2007)

The TV show Monster Garage built an EV for Milwaukee Tools using 384 of their lithium ion battery packs. This EV was at the Battery Beach Burnout EV drag racing last January in Miami. More info on the vehicle here:

http://www.milwaukeetool.com/us/en/news.nsf/vwPressReleases/05B7EA8847B096A48625710A006F210D?Open


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## dfwheelman (May 15, 2008)

Ok so can anyone say what the optimal arrangement would be for a normal car? not a drag racer.... say 96v

The battery packs are cheeper on ebay if you buy it with something like a flash light or sawsall, and you can turn around and sell the saw / flash light without the battery to recoup some cost...


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## dfwheelman (May 15, 2008)

MrCrabs said:


> Where are you finding $100 dewalt packs? just curious, because last time I looked, they were 150.
> The dewalt pack simply contains 10 A123 cells, and here are the specs.
> http://a123systems.textdriven.com/product/pdf/1/ANR26650M1_Datasheet_MARCH_2008.pdf
> 
> ...


when you say "pack" what are you referring to? A single "cell"? or a "pack" in terms of a dewalt 36v "pack"

[edit]
ok, i see....

36v pack * 3 (series) = 96v 2.4ah * 20 parallel = 96v @ 48ah

Wonder what kind of MPH/Range that would average out to


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## Manntis (May 22, 2008)

be careful taking the 36V packs apart - it can be a shocking experience. Tape the tops of each cell before prying off the metal connectors.

I mean, um... *ahem* so I've heard... 

you can get them wholesale for circa $100 all day long and not have to worry about eBay sellers. However - how are you going to reconnect 'em? It takes very vancy equipment to weld connectors back onto the cells, and soldering each one is just asking for a fault in your completed pack.

Major PITA without the right tools.


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## dfwheelman (May 15, 2008)

I dunno, but I think this thing is sweetness

http://www.alibaba.com/product-gs/51898399/LiFePO4_Battery.html

3.2v
55 ah


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