# [EVDL] Ecity Power LiFePO4 Test



## EVDL List (Jul 27, 2007)

Just completed the 2C test. Results still look pretty good. I got to 
say 200 Amps continuous even at only 3V is 600W... thats a fair amount 
of heat.

2C results still show over 100 Ah capacity in this cell. The cell 
case temperature got up to 103 F and the core temp was 115F. The 
voltage averaged around 2.95V

I'm getting ready to run the 3C which is the manufacturers max 
continuous rating.

To answer you question. I'm not sure if I'll do cycle testing. It 
would take a very long time to run 1000-2000-3000 cycles.



> Curtis Keller wrote:
> 
> > Sounds very promising at 1C. Do you have plans to repeated cycle at
> > 'N'C in a test rig?
> ...


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## EVDL List (Jul 27, 2007)

Just completed the 3C test. The cell did fairly well. Voltage sagged 
to about 2.8V, which is kind of what I expected. Everything got hot, 
but what I found interesting is that the 2/0 welding cable that I used 
to connect the cell to the load got hotter then the cell itself!

I would like to post the data. I'm assuming some of you are 
interested. I recorded the data in Excel and saved it as a PDF. can 
anyone suggest a good place to upload a PDF so all can see?




> Roger Heuckeroth wrote:
> 
> > Just completed the 2C test. Results still look pretty good. I got to
> > say 200 Amps continuous even at only 3V is 600W... thats a fair amount
> ...


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## EVDL List (Jul 27, 2007)

> Grant Stockly wrote:
> 
> > At 11:59 AM 3/27/2009, you wrote:
> >> Just completed the 2C test. Results still look pretty good. I got
> ...


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## EVDL List (Jul 27, 2007)

Sounds good. I'll do that. Any other tests that you think I should do?



> [email protected] wrote:
> 
> >
> > Roger,
> ...


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## EVDL List (Jul 27, 2007)

> On 27 Mar 2009 at 17:01, Roger Heuckeroth wrote:
> 
> > can anyone suggest a good place to upload a PDF so all can see?
> 
> ...


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## EVDL List (Jul 27, 2007)

If it is not a very large file you could simply create a .csv file, and 
then paste that into a message for the list.

People could then cut-and-past the csv data into the spreadsheet of 
their choice.

(with the list master's blessing, of course .



> EVDL Administrator wrote:
> > On 27 Mar 2009 at 17:01, Roger Heuckeroth wrote:
> >
> >
> ...


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## EVDL List (Jul 27, 2007)

could you do 4c or 5c?



> Roger Heuckeroth <[email protected]>wrote:
> 
> >
> > On Mar 27, 2009, at 4:54 PM, Grant Stockly wrote:
> ...


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## EVDL List (Jul 27, 2007)

I could do intermittent 4C and 5C, The cell is rated at <3C 
continuous. Are you thinking just to see how low the voltage sags?



> m gol wrote:
> 
> > could you do 4c or 5c?
> >
> ...


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## EVDL List (Jul 27, 2007)

Does ecity specify a minimum voltage to stay above while drawing big amps
for a short time?

Matt 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Roger Heuckeroth
Sent: Sunday, 29 March 2009 1:03 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Ecity Power LiFePO4 Test

I could do intermittent 4C and 5C, The cell is rated at <3C continuous.
Are you thinking just to see how low the voltage sags?



> m gol wrote:
> 
> > could you do 4c or 5c?
> >
> ...


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## EVDL List (Jul 27, 2007)

Not that I have seen. They do specify 2.5V as the low end limit.



> matt wrote:
> 
> > Does ecity specify a minimum voltage to stay above while drawing big
> > amps
> ...


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## EVDL List (Jul 27, 2007)

I was wondering because I was able to pull 450amps for about second, and
then it went down to 200 amps.

Not sure if that was a limitation of the motor or the batteries?



> Roger Heuckeroth <[email protected]>wrote:
> 
> > I could do intermittent 4C and 5C, The cell is rated at <3C
> > continuous. Are you thinking just to see how low the voltage sags?
> ...


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## EVDL List (Jul 27, 2007)

I'll do some more tests this week to test 10 sec pulse current.

Sent from my iPhone



> m gol <[email protected]> wrote:
> 
> > I was wondering because I was able to pull 450amps for about second,
> > and
> ...


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## EVDL List (Jul 27, 2007)

>
>Nichrom heater wire wrapped between two aluminum angles with teeth cut
>into the angle. Its a constant resistance load instead of a constant
>current load, but it works reasonably well.

Have you done any testing with the ThunderSky cells? Do you think 
that these Ecity cells are as good or better than the ThunderSky cells?

I was thinking about getting a few free beat up electric ranges for a 
load machine. With all the elements on it should pull 30-40A. I 
might even be able to do something constructive with the oven 
energy. Cook some beans in the shop while working. : )

It shouldn't be hard to find 5-10 free ranges in Alaska. Real 
Alaskans don't throw anything away, especially if you live outside of 
Anchorage. Just found four ovens on craigslist for free, and another 
two under $50.

Hot tubs with leaks can usually be found cheap or free. That would 
be a good place to put a few kW!


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## EVDL List (Jul 27, 2007)

Im guesing you intend to re-wire those ranges/hot tubs?
A 3000w element at 208v becomes a 0.7w element at 3.2v

Matt 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Grant Stockly
Sent: Monday, 30 March 2009 4:37 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Ecity Power LiFePO4 Test


>
>Nichrom heater wire wrapped between two aluminum angles with teeth cut 
>into the angle. Its a constant resistance load instead of a constant 
>current load, but it works reasonably well.

Have you done any testing with the ThunderSky cells? Do you think that
these Ecity cells are as good or better than the ThunderSky cells?

I was thinking about getting a few free beat up electric ranges for a load
machine. With all the elements on it should pull 30-40A. I might even be
able to do something constructive with the oven energy. Cook some beans in
the shop while working. : )

It shouldn't be hard to find 5-10 free ranges in Alaska. Real Alaskans
don't throw anything away, especially if you live outside of Anchorage.
Just found four ovens on craigslist for free, and another two under $50.

Hot tubs with leaks can usually be found cheap or free. That would be a
good place to put a few kW!


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Version: 7.5.557 / Virus Database: 270.11.4/1976 - Release Date: 27/02/2009
1:27 PM


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## EVDL List (Jul 27, 2007)

> Grant Stockly wrote:
> 
> >
> >>
> ...


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## EVDL List (Jul 27, 2007)

> On 30 Mar 2009 at 9:15, Roger Heuckeroth wrote:
> 
> > The nice thing about the nichrome wire is that I kept on winding the
> > wire until I got the current I was looking for. Each turn would
> ...


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## EVDL List (Jul 27, 2007)

> EVDL Administrator wrote:
> 
> > On 30 Mar 2009 at 9:15, Roger Heuckeroth wrote:
> >
> ...


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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

> Steven Ciciora wrote:
> 
> >
> > Where did you find a small quantity (or at least a $9 quantity) if =
> ...


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## EVDL List (Jul 27, 2007)

>I don't think that will work, because the range elements are designed
>for 220V AC. We are working with 3V DC. The test load was very
>simple to make. It cost me $9 for the roll of nichrom wire and I had
>the 4" aluminum angle sitting in my scrap pile. If you want to look
>for some element to act as a test load it should have a resistance of

I'm interested in testing an entire pack with the stoves.

It would be nice to test an individual cell though.

What diameter/gauge wire did you use? How did you hook a 2/0 cable 
to the nichrom wire?

Grant 

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## EVDL List (Jul 27, 2007)

> Grant Stockly wrote:
> 
> >
> >> I don't think that will work, because the range elements are designed
> ...


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## EVDL List (Jul 27, 2007)

> > I'm interested in testing an entire pack with the stoves.
> >
> > It would be nice to test an individual cell though.
> >
> > What diameter/gauge wire did you use? How did you hook a 2/0 cable
> > to the nichrom wire?
> >
> > Grant
>
>.032" diameter wire
>
>I'll send you a picture of it.

Thanks, I got the picture. It is a very good idea!

Are you using a contactor to turn the load on and off? What do you 
use to recharge the battery? Can one of these large cells be damaged 
by charging it too slowly?



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## EVDL List (Jul 27, 2007)

> Grant Stockly wrote:
> 
> >
> >>> I'm interested in testing an entire pack with the stoves.
> ...


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## EVDL List (Jul 27, 2007)

It is helpful if you read all mails from the poster,
Grant already said he wanted to test a *pack* not a cell.
You can also determine it from his statement that he
wants to dump many kiloWatts. You do not get that from
a single cell, you are pushing it when you reach the
magnitude of a single kW from one cell and then it
must be a big cell, 100Ah does not reach a kW until
you are over 3C which is pushing the cell beyond spec.

Regards,

Cor van de Water
Director HW & Systems Architecture Group
Proxim Wireless Corporation http://www.proxim.com
Email: [email protected] Private: http://www.cvandewater.com
Skype: cor_van_de_water IM: [email protected]
Tel: +1 408 383 7626 magicJack: +1 408 844 3932
Tel: +91 (040)23117400 x203 XoIP: +31877841130

Please consider the environment before printing this e-mail.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of matt
Sent: Monday, March 30, 2009 2:29 PM
To: 'Electric Vehicle Discussion List'
Subject: Re: [EVDL] Ecity Power LiFePO4 Test

Im guesing you intend to re-wire those ranges/hot tubs?
A 3000w element at 208v becomes a 0.7w element at 3.2v

Matt 

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf
Of Grant Stockly
Sent: Monday, 30 March 2009 4:37 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] Ecity Power LiFePO4 Test


>
>Nichrom heater wire wrapped between two aluminum angles with teeth cut 
>into the angle. Its a constant resistance load instead of a constant 
>current load, but it works reasonably well.

Have you done any testing with the ThunderSky cells? Do you think that
these Ecity cells are as good or better than the ThunderSky cells?

I was thinking about getting a few free beat up electric ranges for a
load
machine. With all the elements on it should pull 30-40A. I might even
be
able to do something constructive with the oven energy. Cook some beans
in
the shop while working. : )

It shouldn't be hard to find 5-10 free ranges in Alaska. Real Alaskans
don't throw anything away, especially if you live outside of Anchorage.
Just found four ovens on craigslist for free, and another two under $50.

Hot tubs with leaks can usually be found cheap or free. That would be a
good place to put a few kW!


_______________________________________________
General EVDL support: http://evdl.org/help/
Usage guidelines: http://evdl.org/help/index.html#conv
Archives: http://evdl.org/archive/
Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev



-- 
Internal Virus Database is out-of-date.
Checked by AVG. 
Version: 7.5.557 / Virus Database: 270.11.4/1976 - Release Date:
27/02/2009
1:27 PM


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