# [EVDL] A123 second Source



## EVDL List (Jul 27, 2007)

Hi folk's,

=


I've had no luck trying to buy 26650 batteries from A123, technically cluel=
ess salesmen and no distributors. We use the batteries with tabs for a UPS=
back up on magnetic bearings and our purchasing department told me to find=
a second source since they will only sell "developer kits" which are unacc=
eptible in production.

=


www.k2energy.com or www.peakbattery.com has identical looking cells, probab=
ly from the same manufacturer in China as A123. The order website is http:=
//store.peakbattery.com/index.html and look to be a bit cheaper too for the=
LFP26650P cells 3.2V 2.5ah 9 milli-ohm cells, 50A max. they also have a s=
ame size LFP26650EV that are 3.2ah, 3.2V (28% more energy density but less =
power dump) but only 20A max with 19 milli-ohms internal resistance. They =
said they were the same LiFePO4 chemical composition as the "P" power versi=
on but must have a different anode or cathode. (702) 478-3590 in Hendersonv=
ille, Nevada and seam to be technically knowledgeable. specify "power tabs=
" suffix on the batteries otherwise they won't come with attachments.

=


They also have some T-Sky 90ah batteries I noticed. All require picky batt=
ery balancers though.

=


Have a renewable energy day,

Mark
=

_________________________________________________________________
Hotmail: Trusted email with Microsoft=92s powerful SPAM protection.
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## EVDL List (Jul 27, 2007)

What about the Headway bats from EVcomponents?

http://www.evcomponents.com/SearchResults.asp?Cat=41

Bob Sisson
1993 Geo Metro Convertible Project
Gaithersburg MD

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Mark Hanson
Sent: Tuesday, October 13, 2009 3:42 PM
To: [email protected]
Subject: [EVDL] A123 second Source


Hi folk's,



I've had no luck trying to buy 26650 batteries from A123, technically
clueless salesmen and no distributors. We use the batteries with tabs for a
UPS back up on magnetic bearings and our purchasing department told me to
find a second source since they will only sell "developer kits" which are
unacceptible in production.



www.k2energy.com or www.peakbattery.com has identical looking cells,
probably from the same manufacturer in China as A123. The order website is
http://store.peakbattery.com/index.html and look to be a bit cheaper too for
the LFP26650P cells 3.2V 2.5ah 9 milli-ohm cells, 50A max. they also have a
same size LFP26650EV that are 3.2ah, 3.2V (28% more energy density but less
power dump) but only 20A max with 19 milli-ohms internal resistance. They
said they were the same LiFePO4 chemical composition as the "P" power
version but must have a different anode or cathode. (702) 478-3590 in
Hendersonville, Nevada and seam to be technically knowledgeable. specify
"power tabs" suffix on the batteries otherwise they won't come with
attachments.



They also have some T-Sky 90ah batteries I noticed. All require picky
battery balancers though.



Have a renewable energy day,

Mark

_________________________________________________________________
Hotmail: Trusted email with Microsoft's powerful SPAM protection.
http://clk.atdmt.com/GBL/go/177141664/direct/01/
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## EVDL List (Jul 27, 2007)

On Tue, Oct 13, 2009 at 2:41 PM, Mark Hanson <[email protected]> wro=
te:
> ...
> www.k2energy.com or www.peakbattery.com has identical looking cells, prob=
ably from the same manufacturer in China as A123. The order website is h=
ttp://store.peakbattery.com/index.html and look to be a bit cheaper too for=
the LFP26650P cells 3.2V 2.5ah 9 milli-ohm cells, 50A max. they also ha=
ve a same size LFP26650EV that are 3.2ah, 3.2V (28% more energy density but=
less power dump) but only 20A max with 19 milli-ohms internal resistance. =
They said they were the same LiFePO4 chemical composition as the "P" pow=
er version but must have a different anode or cathode. (702) 478-3590 in He=
ndersonville, Nevada and seam to be technically knowledgeable. specify "=
power tabs" suffix on the batteries otherwise they won't come with attachme=
nts.
> ...

Ian Hooper of ZEVA did some testing of these cells. The 9 milli-ohm
number is a gross exaggeration; the DC resistance as calculated by
voltage drop under load is closer to 22 milli-ohms for the 26650P and
40 milli-ohms for the 26650EV.

At least that's the numbers I calculate based on the charts Ian posted here:

http://www.zeva.com.au/tech/K2/

I've looked at lots of test data for various LiFePO4 cells, and
although many give numbers for internal resistance that compare to
A123, I haven't seen any that come close to meeting those claims.

-Morgan LaMoore

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## EVDL List (Jul 27, 2007)

> Mark Hanson-2 wrote:
> >
> >
> > Hi folk's,
> ...


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## EVDL List (Jul 27, 2007)

The "failure rate" for the recycled DeWalt cells is likely due to 
damage to the integrity of the can when the tab is removed. It is 
_very_ easy to peal a hole in the positive end of can when you peal 
off the tab.

Also, you have to use the right equipment when you weld these cells. 
A capacitive-discharge welder will overheat the cell and damage the 
separator. This could account for some of the "failures" as well.

I am not 100% sure these a "A" cells on Ebay. If the voltage 
on the cells in the box vary more than +/- 0.02 volts, then they are 
likely not A cells, but very likely B (factory seconds) cells.

Bill Dube'


>You can buy A123 M1A cells from an exporter in China via ebay. Search for
>A123 lithium, and look for the green skinned cells. They are the real deal
>fom China BAK. They have not been critically tested to the spec's as defined
>by B&D (DeWalt), so factor that into your consideration of value over price.
>The B&D cells have an approximate 3% failure rate even with critical testing
>and quarantine, so you should anticipate maybe another 2% failure from the
>cells offered on ebay that have not been quarantined.
>
>If you want to test them to a quarantine spec:
>When you receive them, note the OCV on a sticker on the cell. Set them aside
>for 6 months, in a temp and humidity controlled room, and recheck each when
>it's time. If they've dropped more than 10mv, you should not use them.
>
>So there's a second source for you.
>
>Jeff
>
>
>--
>View this message in context: 
>http://www.nabble.com/A123-second-Source-tp25879496p25884467.html
>Sent from the Electric Vehicle Discussion List mailing list archive 
>at Nabble.com.
>
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## EVDL List (Jul 27, 2007)

Hello Bill, I should have provided more detail since there may be some
confusion here, and others may be interested.

The original post I am referring to new cells that have not been tabbed.

The 3% failure rate I noted below affected new, tested M1 cells as delivered
by A123 Systems, and not a distributor or remarketer.
Many thousands of cells were packed in 100pc pallets, and stored. OCV and
impedance was measured later at time of assembly. A failure rate averaging
3% were indicated in multiple lots of 3000 cells where the OCV differential
exceeded -0.250v from average. The average OCV differential of the
remaining 97% did not exceed -10mv (-0.010v)

These cells were quarantined for a longer period, and does account for some
of that failure percentage.

About the new, untabbed cells on ebay:

The M1A cells being offered from the China distributors may have not been
critically tested, nor quarantined to the specifications as defined by A123
Systems. And so might exhibit a higher failure rate than the 3% I
encountered with the volume of M1 cells that were critically tested and
shipped.

I do not know where the term "A" cells, and "B" cells surfaced. And a call
to A123 did not help me either.

There are M1A cells being offered on ebay as new, untabbed cells.

These M1A cells on ebay, from the China BAK production material, appear to
be packed in predicted lot sequence.
The few hundred lot order I have received indicates this. Granted, it is a
small purchase. Not enough for a sample of the scale previously made. On
receipt, each cell was measured for OCV and impedance, and stored away to
identify any high self discharge problems. That's not to say these cells may
have been scrapped in entire lots. It is possible. I have not received an
answer from A123 Systems on how they handle lot yield differentials, and
whether an entire lot would be scrapped when a few flyers were identified in
a given production lot.
I do believe these cells might exhibit a higher failure rate than the
critically tested and quarantined cells delivered to B&D. Only time will
tell.

Hopefully that clears up my original post.

And Thank You for your promotion of these cells and the KillaCycle to the
community!

Jeff








> Bill Dube wrote:
> >
> > The "failure rate" for the recycled DeWalt cells is likely due to
> > damage to the integrity of the can when the tab is removed. It is
> ...


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## EVDL List (Jul 27, 2007)

I completely agree.... know some people with first hand experience...

Sure they're one of the highest energy density lifepo4 cells out there, but 
not great for high C-rate discharge.



> The K2 cells - 26650E and 26650EV, as you'll be hearing from others; do 
> not


> perform as advertized. A waste of money if you intent to use them at


> discharge rates exceeding 1C.
> Jeff

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## EVDL List (Jul 27, 2007)

"A capacitive-discharge welder"
which spot welder can you use?




> Bill Dube <[email protected]> wrote:
> 
> > The "failure rate" for the recycled DeWalt cells is likely due to
> > damage to the integrity of the can when the tab is removed. It is
> ...


----------



## EVDL List (Jul 27, 2007)

4000 amp double-pulse inverter welder.

Bill D.


At 03:24 PM 10/14/2009, you wrote:
>"A capacitive-discharge welder"
>which spot welder can you use?
>
>
>


> Bill Dube <[email protected]> wrote:
> >
> > > The "failure rate" for the recycled DeWalt cells is likely due to
> > > damage to the integrity of the can when the tab is removed. It is
> ...


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## EVDL List (Jul 27, 2007)

> Bill Dube <[email protected]> wrote:
> > 4000 amp double-pulse inverter welder.
> >
> > Bill D.
> ...


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## EVDL List (Jul 27, 2007)

Bill touched on that before:
"you have to use the right equipment when you weld these cells.
A capacitive-discharge welder will overheat the cell and damage the
separator."

I know A123 does NOT recommend using a CD welder



> Morgan LaMoore <[email protected]> wrote:
> 
> > On Wed, Oct 14, 2009 at 4:37 PM, Bill Dube <[email protected]>
> > wrote:
> ...


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## EVDL List (Jul 27, 2007)

what about this one?
http://www.sunstonespotwelders.com/spot-welders-pulse-arc.php



> Travis Gintz <[email protected]> wrote:
> 
> > Bill touched on that before:
> > "you have to use the right equipment when you weld these cells.
> ...


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## EVDL List (Jul 27, 2007)

A capacitive discharge welder does not have the control needed to limit damage to the cell.

It takes a certain amount of energy to weld, lets call that Q.

You can get Q by applying a small amount of heat for a long time or more heat for a much shorter amount of time.
But the heat wants to migrate away. So if you can get a short enough burst, you can weld the tab to the cell and not give it enough time to migrate into and damage the cell. Damage like this will show up over teh life of the cell, not always right away.

When I investigated this, I found you can't even use the Miyachi single phase versions that they used for nicad and NiMh as they use power line zero crossing and set the minimum pulse width to 17ms. From what I read anything over 12ms is pushing it for Lithium based cells and 8-10ms is more like it. The initial pulse is shorter and less amps to blow off the oxides in the weldarea and prep the area for the main weld.

If you go thru the Unitek Miyachi website they have lots of information on this. You need to look int he precision resistance welding section on series welding. So called because you use a dual head and the weld is thru one electrode the tab, the top of the cell and back thru the tab into the other trode. 2 weld nuggets in series.



> Bill Dube <[email protected]> wrote:
> 
> > > 4000 amp double-pulse inverter welder.
> > >
> ...


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## EVDL List (Jul 27, 2007)

What is the best brand inverter welder?



> Bill Dube <[email protected]> wrote:
> 
> > 4000 amp double-pulse inverter welder.
> >
> ...


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## EVDL List (Jul 27, 2007)

Does anyone know the real difference between these inverter welder and 
a capacitive discharge welder? I assume both welders hold the 
electrons in a capacitor bank. That is the only way I can conceive of 
releasing that much current in such a short time (<12 ms).

I have a Miller 350P inverter welder. From what I understand it uses 
an inverter to boost the voltage to the primary side of a transformer 
at a much higher frequency than 60 HZ. This allows the use of a 
smaller, more efficient transformer to put out the DC current. Does 
an inverter battery tab spot welder work the same? I would think not, 
because the inductance of the transformer would not allow such a short 
pulse.



> Jeff Shanab wrote:
> 
> > A capacitive discharge welder does not have the control needed to
> > limit damage to the cell.
> ...


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## EVDL List (Jul 27, 2007)

> evbones wrote:
> >
> > OCV and impedance was measured later at time of assembly.
> >
> ...


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