Energy in a TS-LFP100AHA between 3.4-4v

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Energy in a TS-LFP100AHA between 3.4-4v

David Nelson-5
I did a rough measurement of the amount of energy in a TS-LFP100AHA
cell I received in the EV Components order which arrived at the end of
December 2009.

I do not have a recording system so this was done by hand. First I
used a BK Precision 1761 bench top power supply and an Extech EX830
meter. First I used the EX830 to set the voltage limit on the power
supply. Then I hooked up the cell and let it charge to the desired
voltage until the current dropped below 4ma. Next I disconnected the
cell and set the voltage limit of the power supply to 4.00v as
measured with the EX830. I powered off the power supply, then I hooked
up the EX830 to the cell terminals and leads from the cell to the
power supply and set the power supply display to read current in amps.
I then turned on the power supply and read and recorded the current
and voltage. At 1 minute intervals I recorded the voltage at the cell
terminals and the current displayed by the power supply. I recorded
data every minute until the current was well below 100mA. Then I
recorded at longer intervals. I stopped recording when the current was
below 40mA.

I entered the data (time, volts, amps) into a spreadsheet and
calculated the Wh and Ah for each time interval using the average
voltage and average current for the interval in question. My results
are:

Start voltage: 3.600
End voltage: 4.00 (my meter switches to 2 decimal places at 3.98V)
Watt-hours: 0.87
Amp-hours: 0.22

Start voltage: 3.500
End voltage: 4.00
Watt-hours: 1.18
Amp-hours: 0.36

Start voltage: 3.397
End voltage: 4.00
Watt-hours: 2.42
Amp-hours: 0.66

What I would like to know is at what current would a cell terminal
voltage read 4.00V but the OC voltage would settle to be 3.4V. This
might be useful in designing charging algorithms for fast charging up
to the desired cutoff voltage. Since there seems to be very little
energy above 3.4V why bother going above it other than to shorten
charging time?

Comments? Are my calculations within reason?

--
David D. Nelson
http://evalbum.com/1328

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Re: Energy in a TS-LFP100AHA between 3.4-4v

Pestka, Dennis J
David;

Based on the data you've collected, maybe you can help me understand
something I've been struggling with.

My 156 nominal pack, 12V x 13 batteries usually sets fully charged at ~
167V - 12.85V per battery.
My Raptor controller is limited to 180VDC max.

If these Lithium's ever get to a point where I can afford them, how do
you calculate how many you would need to replace a 156V nominal pack?
Do you use the nominal voltage of 3.2 per cell, finish voltage of 4.0,
or something in between.
When you're looking at 49 to 50 cells, this makes a huge difference.
49 cells at 3.2 = 157V, and 49 cells at 4.0 = 196V.

Any explanation would be greatly appreciated.


Thanks;
Dennis                                            
Elsberry, MO                              
http://www.evalbum.com/1366 


                                                   


-----Original Message-----
From: David Nelson [mailto:[hidden email]]
Sent: Monday, February 01, 2010 10:45 PM
To: Electric Vehicle Discussion List
Subject: [EVDL] Energy in a TS-LFP100AHA between 3.4-4v

I did a rough measurement of the amount of energy in a TS-LFP100AHA cell
I received in the EV Components order which arrived at the end of
December 2009.

I do not have a recording system so this was done by hand. First I used
a BK Precision 1761 bench top power supply and an Extech EX830 meter.
First I used the EX830 to set the voltage limit on the power supply.
Then I hooked up the cell and let it charge to the desired voltage until
the current dropped below 4ma. Next I disconnected the cell and set the
voltage limit of the power supply to 4.00v as measured with the EX830. I
powered off the power supply, then I hooked up the EX830 to the cell
terminals and leads from the cell to the power supply and set the power
supply display to read current in amps.
I then turned on the power supply and read and recorded the current and
voltage. At 1 minute intervals I recorded the voltage at the cell
terminals and the current displayed by the power supply. I recorded data
every minute until the current was well below 100mA. Then I recorded at
longer intervals. I stopped recording when the current was below 40mA.

I entered the data (time, volts, amps) into a spreadsheet and calculated
the Wh and Ah for each time interval using the average voltage and
average current for the interval in question. My results
are:

Start voltage: 3.600
End voltage: 4.00 (my meter switches to 2 decimal places at 3.98V)
Watt-hours: 0.87
Amp-hours: 0.22

Start voltage: 3.500
End voltage: 4.00
Watt-hours: 1.18
Amp-hours: 0.36

Start voltage: 3.397
End voltage: 4.00
Watt-hours: 2.42
Amp-hours: 0.66

What I would like to know is at what current would a cell terminal
voltage read 4.00V but the OC voltage would settle to be 3.4V. This
might be useful in designing charging algorithms for fast charging up to
the desired cutoff voltage. Since there seems to be very little energy
above 3.4V why bother going above it other than to shorten charging
time?

Comments? Are my calculations within reason?

--
David D. Nelson
http://evalbum.com/1328



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Re: Energy in a TS-LFP100AHA between 3.4-4v

David Nelson-5
I know what you mean about trying to pick the correct # of cells. I
have 18 buddy pairs (200Ah per pair) in my pack. I have a Zivan NG1
programmed for 48V of T-875s. I've been playing with the voltage
adjustment pot to get it to charge my new pack without going over 70V
and yet still have a reasonably quick charge by not entering the
constant voltage stage too early. As I have watched the pack voltage I
find it sits between 60-62V after the top charge has been bled off.
This is with the batteries at around 50F. As I watch the pack voltage
during charge it sits at 60.4-60.7V for quite a while, charging at
about 18A. When it gets to about 61.5V or so the voltage begins to
climb rather rapidly even though the charger has backed off to the 6A
acceptance stage (remember the algorithm is for Lead Acid batteries).
The voltage climbs rather quickly up to 70.5V. The charger at this
point is trying to keep the voltage from going over this point so it
has cut back to somewhere under 0.5A. Yesterday I turned down the
voltage adjustment pot a 1/4 turn during this phase of charging and
the pack voltage dropped to 70.3V the charger went to drawing only 16W
from the wall for a minute or so and the was back up to 35W from the
wall which turns out to be about 0.5A into the batteries. I have a
slight parasitic load on my battery pack and I don't know how much
this is so some of the charge goes to support that. After charging to
70+V the pack voltage drops to about 68V after 15 minutes or so.
Remember I have a slight parasitic load. I don't have a numeric scale
on my volt meter but the pack is in the 65V or higher range in the
morning after sitting all night. The first acceleration brings the
pack voltage down to 61V or less.

I just went out and measured the voltage on the two cells I used in my
3.4-4V test set. One of them has been sitting for 22 hours and is at
3.873V and one has been sitting 3 days or so and is at 3.777V. This is
with no load and my shop is at about 60F.

I've been using 3.4V as my nominal voltage knowing it will sag a
little under load. If your controller is disconnected from your pack
during charge and you only charge to say 3.8Vpc then you aren't
leaving too much unused charge capacity (assuming you aren't finishing
with a high current) and it will likely drop from 190V to 180V (50
cells) over night, especially if you have any type of load on your
pack. My DC-DC converter has an always on side to it. If you regularly
charge to 3.6V and only periodically "top balance" then it wouldn't be
an issue going with 50 cells. From my measurements I don't think an
unused 0.7% is an issue. It may even lengthen the calendar life of the
pack. Remember that in my tests I left the cells on for an extended
period of time to reach my desired start voltage for the tests. I
think the last test I left the cell hooked up over night.

I'm still learning but HTH,

On Tue, Feb 2, 2010 at 1:03 PM, Pestka, Dennis J
<[hidden email]> wrote:

> David;
>
> Based on the data you've collected, maybe you can help me understand
> something I've been struggling with.
>
> My 156 nominal pack, 12V x 13 batteries usually sets fully charged at ~
> 167V - 12.85V per battery.
> My Raptor controller is limited to 180VDC max.
>
> If these Lithium's ever get to a point where I can afford them, how do
> you calculate how many you would need to replace a 156V nominal pack?
> Do you use the nominal voltage of 3.2 per cell, finish voltage of 4.0,
> or something in between.
> When you're looking at 49 to 50 cells, this makes a huge difference.
> 49 cells at 3.2 = 157V, and 49 cells at 4.0 = 196V.
>
> Any explanation would be greatly appreciated.
>
>
> Thanks;
> Dennis
> Elsberry, MO
> http://www.evalbum.com/1366
>
>
>
>
>
> -----Original Message-----
> From: David Nelson [mailto:[hidden email]]
> Sent: Monday, February 01, 2010 10:45 PM
> To: Electric Vehicle Discussion List
> Subject: [EVDL] Energy in a TS-LFP100AHA between 3.4-4v
>
> I did a rough measurement of the amount of energy in a TS-LFP100AHA cell
> I received in the EV Components order which arrived at the end of
> December 2009.
>
> I do not have a recording system so this was done by hand. First I used
> a BK Precision 1761 bench top power supply and an Extech EX830 meter.
> First I used the EX830 to set the voltage limit on the power supply.
> Then I hooked up the cell and let it charge to the desired voltage until
> the current dropped below 4ma. Next I disconnected the cell and set the
> voltage limit of the power supply to 4.00v as measured with the EX830. I
> powered off the power supply, then I hooked up the EX830 to the cell
> terminals and leads from the cell to the power supply and set the power
> supply display to read current in amps.
> I then turned on the power supply and read and recorded the current and
> voltage. At 1 minute intervals I recorded the voltage at the cell
> terminals and the current displayed by the power supply. I recorded data
> every minute until the current was well below 100mA. Then I recorded at
> longer intervals. I stopped recording when the current was below 40mA.
>
> I entered the data (time, volts, amps) into a spreadsheet and calculated
> the Wh and Ah for each time interval using the average voltage and
> average current for the interval in question. My results
> are:
>
> Start voltage: 3.600
> End voltage: 4.00 (my meter switches to 2 decimal places at 3.98V)
> Watt-hours: 0.87
> Amp-hours: 0.22
>
> Start voltage: 3.500
> End voltage: 4.00
> Watt-hours: 1.18
> Amp-hours: 0.36
>
> Start voltage: 3.397
> End voltage: 4.00
> Watt-hours: 2.42
> Amp-hours: 0.66
>
> What I would like to know is at what current would a cell terminal
> voltage read 4.00V but the OC voltage would settle to be 3.4V. This
> might be useful in designing charging algorithms for fast charging up to
> the desired cutoff voltage. Since there seems to be very little energy
> above 3.4V why bother going above it other than to shorten charging
> time?
>
> Comments? Are my calculations within reason?
>
> --
> David D. Nelson
> http://evalbum.com/1328
>
>
>
> _______________________________________________
> General support: http://evdl.org/help/
> Unsubscribe: http://www.evdl.org/help/index.html#usub
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archive / Forum: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
>



--
David D. Nelson
http://evalbum.com/1328

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Re: Energy in a TS-LFP100AHA between 3.4-4v

Mark Fowler-3
In reply to this post by Pestka, Dennis J
Hi Dennis,

The important number to consider is the max voltage during charge.

(Odyssey lead acid batts use a finishing charge of 14.8 v per batt for example)

Anyway, you need to make sure that whatever equipment you have
connected to your battery pack (controller, dc/dc, heater etc) will
not let the smoke out when your charger is at its maximum voltage
during the charge cycle.

Controllers are usually disconnected from the pack when they are not
running, so it is possible to take the pack a little higher than the
controller's maximum spec as long as you remember to let the voltage
drop back down into the safe zone before starting the controller.

So, to answer your question, get the peak voltage specs for each piece
of equipment on your pack. Take the lowest of these values - this is
your safe maximum voltage.
(eg 180V for your controller)
Take the peak charge voltage of the cells you are considering.
(eg 4.0V)
180 / 4.0 = 45 - You can safely charge 45 cells to 4.0v per cell.

45 x 3.2 = 144 - Your pack will have a nominal voltage of 144V

Mark

On Wed, Feb 3, 2010 at 8:03 AM, Pestka, Dennis J
<[hidden email]> wrote:

> David;
>
> Based on the data you've collected, maybe you can help me understand
> something I've been struggling with.
>
> My 156 nominal pack, 12V x 13 batteries usually sets fully charged at ~
> 167V - 12.85V per battery.
> My Raptor controller is limited to 180VDC max.
>
> If these Lithium's ever get to a point where I can afford them, how do
> you calculate how many you would need to replace a 156V nominal pack?
> Do you use the nominal voltage of 3.2 per cell, finish voltage of 4.0,
> or something in between.
> When you're looking at 49 to 50 cells, this makes a huge difference.
> 49 cells at 3.2 = 157V, and 49 cells at 4.0 = 196V.
>
> Any explanation would be greatly appreciated.
>
>
> Thanks;
> Dennis
> Elsberry, MO
> http://www.evalbum.com/1366

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Re: Energy in a TS-LFP100AHA between 3.4-4v

Jeff Shanab
In reply to this post by David Nelson-5
I have contemplated this a lot myself and came to the conclusion that it
depends on whatever is your limit.
For me The charger can handle higher or lower so no issue but the dc-dc
and emeter need to be considered.

I was worried becasue I have a higher voltage pack and I think the error
in approximation compounds

so 288V of lead is 24 12V modules. But 12V is dead. Really we look at is as
    Equalize               + 10%    = 389 (374 is about as high as I
have gone)
    End of charge         14.77/each   = 355
    nominal                  12.88               = 307 the OCV voltage
after charge and settle
    cruise at 100A      ~280V down
    End of Discharge   10.5/each      = 252

looking at lithium
    max         3.65      97 modules
    nom         3.2        96 modules
    cruise      3.0        291V if 97, ok LiFePo4 is stiffer. That is good
    min          2.5        100 modules, but if I used 97, i could go
lower or just change my ,im to 2.6

So i would probably go with 96 modules. and that works out to 4 lithium
cells for every 6 lead acid cells
ie 4 liFePo4 = one 12V battery and that tracks with what has seem to
become the defacto standard.

So is it your dc-dc that will give up the ghost if you raise the end of
charge voltage or will it brown out at a lower end of discharge voltage
that is possible but not a good idea anyway?
   

> David;
>
> Based on the data you've collected, maybe you can help me understand
> something I've been struggling with.
>
> My 156 nominal pack, 12V x 13 batteries usually sets fully charged at ~
> 167V - 12.85V per battery.
> My Raptor controller is limited to 180VDC max.
>
> If these Lithium's ever get to a point where I can afford them, how do
> you calculate how many you would need to replace a 156V nominal pack?
> Do you use the nominal voltage of 3.2 per cell, finish voltage of 4.0,
> or something in between.
> When you're looking at 49 to 50 cells, this makes a huge difference.
> 49 cells at 3.2 = 157V, and 49 cells at 4.0 = 196V.
>
> Any explanation would be greatly appreciated.
>
>
> Thanks;
> Dennis                                            
> Elsberry, MO                              
> http://www.evalbum.com/1366 
>
>  

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Re: Energy in a TS-LFP100AHA between 3.4-4v

Elithion
In reply to this post by David Nelson-5
David Nelson-5 wrote
I did a rough measurement of the amount of energy in a TS-LFP100AHA
...
End voltage: 4.00
...
What I would like to know is at what current would a cell terminal
voltage read 4.00V but the OC voltage would settle to be 3.4V.
Figuring that out empirically would be easy. But the number would change soon: the cell resistance changes with age and temperature, and is especially variable at the end of charge. So, knowing that fixed number would be pretty useless. There are some complex algorithms that allow you to get the cell resistance in real time, with varying degrees of success, based on a cell model, historical data and environmental information. But, unless your 1st name is "Dr.", I wouldn't try it.

David Nelson-5 wrote
Since there seems to be very little
energy above 3.4V why bother going above it other than to shorten
charging time?
(And shorted cell life as well, one would think.)

To quote a TS executive who was asked repeatedly that question (this is 2nd hand info): "Because you must!", and refuses to say why, or what happens if you don't.

To quote a university professor who has a very intimate understanding of Li-Ion cell chemistry: Thundersky cells have a mixed chemistry (Cobalt and Iron Phosphate) and the Cobalt component needs to be brought to 4.2 V after each charge, to achieve a chemical balance (not to be confused with battery balancing: bringing all cells to the same SOC). That still doesn't tell me what happens if you don't.

Like I said before, I am not a chemist, so I have no idea what they are talking about, but I believe they do, so I'll oblige.


Davide Andrea
Elithion
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Re: Energy in a TS-LFP100AHA between 3.4-4v

Pestka, Dennis J
In reply to this post by Jeff Shanab
Thanks to David and all the other great responses.

Thanks;
Dennis                                            
Elsberry, MO                              
http://www.evalbum.com/1366 

                                                   
 

-----Original Message-----
From: Jeff Shanab [mailto:[hidden email]]
Sent: Wednesday, February 03, 2010 11:35 AM
To: [hidden email]
Subject: Re: [EVDL] Energy in a TS-LFP100AHA between 3.4-4v

I have contemplated this a lot myself and came to the conclusion that it
depends on whatever is your limit.
For me The charger can handle higher or lower so no issue but the dc-dc
and emeter need to be considered.

I was worried becasue I have a higher voltage pack and I think the error
in approximation compounds

so 288V of lead is 24 12V modules. But 12V is dead. Really we look at is
as
    Equalize               + 10%    = 389 (374 is about as high as I
have gone)
    End of charge         14.77/each   = 355
    nominal                  12.88               = 307 the OCV voltage
after charge and settle
    cruise at 100A      ~280V down
    End of Discharge   10.5/each      = 252

looking at lithium
    max         3.65      97 modules
    nom         3.2        96 modules
    cruise      3.0        291V if 97, ok LiFePo4 is stiffer. That is
good
    min          2.5        100 modules, but if I used 97, i could go
lower or just change my ,im to 2.6

So i would probably go with 96 modules. and that works out to 4 lithium
cells for every 6 lead acid cells ie 4 liFePo4 = one 12V battery and
that tracks with what has seem to become the defacto standard.

So is it your dc-dc that will give up the ghost if you raise the end of
charge voltage or will it brown out at a lower end of discharge voltage
that is possible but not a good idea anyway?
   

> David;
>
> Based on the data you've collected, maybe you can help me understand
> something I've been struggling with.
>
> My 156 nominal pack, 12V x 13 batteries usually sets fully charged at
> ~ 167V - 12.85V per battery.
> My Raptor controller is limited to 180VDC max.
>
> If these Lithium's ever get to a point where I can afford them, how do

> you calculate how many you would need to replace a 156V nominal pack?
> Do you use the nominal voltage of 3.2 per cell, finish voltage of 4.0,

> or something in between.
> When you're looking at 49 to 50 cells, this makes a huge difference.
> 49 cells at 3.2 = 157V, and 49 cells at 4.0 = 196V.
>
> Any explanation would be greatly appreciated.
>
>
> Thanks;
> Dennis                                            
> Elsberry, MO                              
> http://www.evalbum.com/1366
>
>  



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Re: Energy in a TS-LFP100AHA between 3.4-4v

Jeffrey Jenkins
In reply to this post by Elithion
Elithion wrote
...[why you have to charge to 4.2V]...
(And shorted cell life as well, one would think.)

To quote a TS executive who was asked repeatedly that question (this is 2nd hand info): "Because you must!", and refuses to say why, or what happens if you don't.

To quote a university professor who has a very intimate understanding of Li-Ion cell chemistry: Thundersky cells have a mixed chemistry (Cobalt and Iron Phosphate) and the Cobalt component needs to be brought to 4.2 V after each charge, to achieve a chemical balance (not to be confused with battery balancing: bringing all cells to the same SOC). That still doesn't tell me what happens if you don't.

Like I said before, I am not a chemist, so I have no idea what they are talking about, but I believe they do, so I'll oblige.
This caught my eye and I think it is really important to get to the bottom of this... surely ThunderSky realizes that there is little or no capacity above 3.45V, yet they still state in their Fine Manual that you should charge to 4.2V. Why in the world would they suggest that unless there was some good reason for it?

I'm not a doctor, nor do I even play one on TV, but I have to say this whole "what voltage to end charging at" issue really does merit some deeper digging. After all, lead-acid cells deliver 2.14V per cell when full charged but we routinely charge them at 2.4V cell (and occasionally equalize them at ~2.6V per cell) and the reason is to overcome "sulfation"... might not something similar be happening inside the LFP cells? Seems reasonable, but it is not known for sure. Any academic references would be most appreciated.

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Re: Energy in a TS-LFP100AHA between 3.4-4v

Mike Golub-2
In reply to this post by Elithion
according the TS data sheet there is no Cobalt in the battery

On Wed, Feb 3, 2010 at 11:53 AM, Elithion <[hidden email]> wrote:

>
>
> David Nelson-5 wrote:
> >
> > I did a rough measurement of the amount of energy in a TS-LFP100AHA
> > ...
> > End voltage: 4.00
> > ...
> > What I would like to know is at what current would a cell terminal
> > voltage read 4.00V but the OC voltage would settle to be 3.4V.
> >
>
> Figuring that out empirically would be easy. But the number would change
> soon: the cell resistance changes with age and temperature, and is
> especially variable at the end of charge. So, knowing that fixed number
> would be pretty useless. There are some complex algorithms that allow you
> to
> get the cell resistance in real time, with varying degrees of success,
> based
> on a cell model, historical data and environmental information. But, unless
> your 1st name is "Dr.", I wouldn't try it.
>
>
> David Nelson-5 wrote:
> >
> > Since there seems to be very little
> > energy above 3.4V why bother going above it other than to shorten
> > charging time?
> >
>
> (And shorted cell life as well, one would think.)
>
> To quote a TS executive who was asked repeatedly that question (this is 2nd
> hand info): "Because you must!", and refuses to say why, or what happens if
> you don't.
>
> To quote a university professor who has a very intimate understanding of
> Li-Ion cell chemistry: Thundersky cells have a mixed chemistry (Cobalt and
> Iron Phosphate) and the Cobalt component needs to be brought to 4.2 V after
> each charge, to achieve a chemical balance (not to be confused with battery
> balancing: bringing all cells to the same SOC). That still doesn't tell me
> what happens if you don't.
>
> Like I said before, I am not a chemist, so I have no idea what they are
> talking about, but I believe they do, so I'll oblige.
>
>
>
>
> -----
> Davide Andrea
> http://liionbms.com/php/index.php Elithion
> --
> View this message in context:
> http://n4.nabble.com/Energy-in-a-TS-LFP100AHA-between-3-4-4v-tp1459547p1461717.html
> Sent from the Electric Vehicle Discussion List mailing list archive at
> Nabble.com.
>
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Re: Energy in a TS-LFP100AHA between 3.4-4v

Jukka Järvinen-3
Well.. I have to say it has nothing to do with Cobalt. TS used mixed
cathodes in LCPs. LFP is anohter animal.

The reasons might not be clear yet but empirically it has been proven
that there is better battery performance after 4000 cycles if you do
the 4,25V EOC every now and then. I bet all of us (EV geeks) wish to
have as long lifetime out of the batteries as we can. Chemists and
battery-Dr-persons optimize their thinking in more .. chemical way. We
just wish to be practical and take care of our precious cells.

A123 might be different and I believe it just has something to do with
their powder composition. Particle size is smaller and poweder more
fine. To get more power to hybrid vehicle and tool batteries. TS makes
optimal and reasonable batteries for full BEVs. They just are so
lovely and straight forward piece of tech.


-akkuJukka

(driving with TS cells since 2002...and the love story continues... ;)


2010/2/5 m gol <[hidden email]>:

> according the TS data sheet there is no Cobalt in the battery
>
> On Wed, Feb 3, 2010 at 11:53 AM, Elithion <[hidden email]> wrote:
>
>>
>>
>> David Nelson-5 wrote:
>> >
>> > I did a rough measurement of the amount of energy in a TS-LFP100AHA
>> > ...
>> > End voltage: 4.00
>> > ...
>> > What I would like to know is at what current would a cell terminal
>> > voltage read 4.00V but the OC voltage would settle to be 3.4V.
>> >
>>
>> Figuring that out empirically would be easy. But the number would change
>> soon: the cell resistance changes with age and temperature, and is
>> especially variable at the end of charge. So, knowing that fixed number
>> would be pretty useless. There are some complex algorithms that allow you
>> to
>> get the cell resistance in real time, with varying degrees of success,
>> based
>> on a cell model, historical data and environmental information. But, unless
>> your 1st name is "Dr.", I wouldn't try it.
>>
>>
>> David Nelson-5 wrote:
>> >
>> > Since there seems to be very little
>> > energy above 3.4V why bother going above it other than to shorten
>> > charging time?
>> >
>>
>> (And shorted cell life as well, one would think.)
>>
>> To quote a TS executive who was asked repeatedly that question (this is 2nd
>> hand info): "Because you must!", and refuses to say why, or what happens if
>> you don't.
>>
>> To quote a university professor who has a very intimate understanding of
>> Li-Ion cell chemistry: Thundersky cells have a mixed chemistry (Cobalt and
>> Iron Phosphate) and the Cobalt component needs to be brought to 4.2 V after
>> each charge, to achieve a chemical balance (not to be confused with battery
>> balancing: bringing all cells to the same SOC). That still doesn't tell me
>> what happens if you don't.
>>
>> Like I said before, I am not a chemist, so I have no idea what they are
>> talking about, but I believe they do, so I'll oblige.
>>
>>
>>
>>
>> -----
>> Davide Andrea
>> http://liionbms.com/php/index.php Elithion
>> --
>> View this message in context:
>> http://n4.nabble.com/Energy-in-a-TS-LFP100AHA-between-3-4-4v-tp1459547p1461717.html
>> Sent from the Electric Vehicle Discussion List mailing list archive at
>> Nabble.com.
>>
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Re: Energy in a TS-LFP100AHA between 3.4-4v

Jeffrey Jenkins
Jukka Järvinen-3 wrote
...
The reasons might not be clear yet but empirically it has been proven
that there is better battery performance after 4000 cycles if you do
the 4,25V EOC every now and then.
...
(driving with TS cells since 2002...and the love story continues... ;)
If these are the same cells and you cycle them on a daily basis then you must be doing something right! If you don't mind, I'm curious about a few details of your installation:

1. What voltage do you charge each cell to? Do you occasionally take them to 4,25V?
2. If you use a BMS, at what voltage does it start shunting (if it does at all)?
3. How have you stopped the cells from swelling? By using the hardware supplied by TS?
4. What is the maximum current you routinely draw from the pack?

Thanks!
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Re: Energy in a TS-LFP100AHA between 3.4-4v

Jeff Shanab
In reply to this post by David Nelson-5
>
> Well.. I have to say it has nothing to do with Cobalt. TS used mixed
> cathodes in LCPs. LFP is anohter animal.
>
> The reasons might not be clear yet but empirically it has been proven
> that there is better battery performance after 4000 cycles if you do
> the 4,25V EOC every now and then. I bet all of us (EV geeks) wish to
> have as long lifetime out of the batteries as we can. Chemists and
> battery-Dr-persons optimize their thinking in more .. chemical way. We
> just wish to be practical and take care of our precious cells.
>
> A123 might be different and I believe it just has something to do with
> their powder composition. Particle size is smaller and poweder more
> fine. To get more power to hybrid vehicle and tool batteries. TS makes
> optimal and reasonable batteries for full BEVs. They just are so
> lovely and straight forward piece of tech.
>
>
> -akkuJukka

I was at one time looking into making my own batteries so i did some
research in this area.

First of all understand that the lithium ion battery is an intercalation
battery, The lithium ions get stuffed into the spaces between the doped
anode and cathode.
There is not a chemical change in the electrode material like there is
in lead-acid. There is one in the electrolyte. In the lithium cobalt
days the electrolyte was lithium-hexo-flourate and teh amount of lithium
changed. If you over voltaged or let them get warm, you could
dissassociate the hexo flourate part and make it useless. it also would
end up plugging the spaces inthe anode or cathode and reduced your
capacity.  Nowadays the LiFePo4 cells use an different electrolyte, it
is safer(stay away from halogenated rings!) and has less of a problem
with heat.

Also the pre-cursers used to make the anode and cathod are now being
made with more uniform and regulated structure which helps ward off the
blocked pores style problems.

Over charging every time is gonna wear things out, Event he new
electrolyte can only take so much. I suspect that a full charge once in
a while helps warm and expand he structure and otherwise get ions
diffused deeply in and out of the anode and cathode and helps "clean
them out" before they get permanently plugged up.



Funny side note: :Listening to France24 a 24 news channel talking about
the car industry. There was a debate and they were talking about how the
minimum number of units for profitability has gone up to 6 million and
that is one of  the reasons we have seen so many mergers and
acquisitions.  Because this was in the wake of Toyota's 1-2 punch of bad
luck, the one proponent stated saying basically what I have said, that
the day and age one panicia fuel is gone.  He started talking about the
future being in electric cars and mentioned tesla.nissan and BYD.
Europe "gets" it.

But one of the guys then starts down the negative path and says
something like well we don't know yet about safety, there hasn't been an
accident in an eletric vehicle with acid spraying all over the place....

LOL, idiot

I was also surprise there has not been talk on this list from that
announcement from tesla that they won't make the current roadster past
2011 and don't expect any income form electric cars in 2011.  I don't
think it is as severe as the press made it out to be as the way it was
said is vauge.. "no made in current form because of upstream changes at
lotus..." The cut-down version
http://sanjose.bizjournals.com/sanjose/stories/2010/01/25/daily109.html

    They also got the grant and it is specified that it will be used for
the S-sedan due in 2012 and another factory to make EV parts for other
car makers!






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Re: Energy in a TS-LFP100AHA between 3.4-4v

Jukka Järvinen-3
In reply to this post by Jeffrey Jenkins
2010/2/5 Jeffrey Jenkins <[hidden email]>:
>
>
> Jukka Järvinen-3 wrote:
>> The reasons might not be clear yet but empirically it has been proven
>> that there is better battery performance after 4000 cycles if you do
>> the 4,25V EOC every now and then.
>> ...
>> (driving with TS cells since 2002...and the love story continues... ;)

I do have cells from the original patch.. Green LCPs.. but I have been
driving more cells in cars (buses, trucks, vans, passenger cars,
wheelchairs, boats, bicycles, + another 100 different protoes) during
past 8 years than just one set or pack.

I base my opinion on a LOT of personal test drive kilometers and great
deal of lab testing. I was allowed to have opinions after the
non-competes melt away last December but ALL data is confidential...
bummer.


> If these are the same cells and you cycle them on a daily basis then you
> must be doing something right! If you don't mind, I'm curious about a few
> details of your installation:
>
> 1. What voltage do you charge each cell to? Do you occasionally take them to
> 4,25V?

Yes. End of charge is quite flexible thing.

> 2. If you use a BMS, at what voltage does it start shunting (if it does at
> all)?

No shunting. Active balancing. See the patent.

http://v3.espacenet.com/publicationDetails/biblio?DB=EPODOC&adjacent=true&locale=fi_FI&FT=D&date=20080131&CC=FI&NR=118656B1&KC=B1


> 3. How have you stopped the cells from swelling? By using the hardware
> supplied by TS?

No. I use strapping tool from ITA tools:
http://www.itatools.it/eng/ita20.htm


> 4. What is the maximum current you routinely draw from the pack?

I design pack in a way that it takes hours to deplete. So less than 1C
nominal. Peak in normal use is less than 3C.

For NEDRA-type applications I stay in 10C region.

-akkuJukka

>
> Thanks!
>
> --
> View this message in context: http://n4.nabble.com/Energy-in-a-TS-LFP100AHA-between-3-4-4v-tp1459547p1470085.html
> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.
>
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Re: Energy in a TS-LFP100AHA between 3.4-4v

Jukka Järvinen-3
In reply to this post by Jeff Shanab
2010/2/5 Jeff Shanab <[hidden email]>:
> capacity.  Nowadays the LiFePo4 cells use an different electrolyte, it
> is safer(stay away from halogenated rings!) and has less of a problem
> with heat.

The problem is still there. It is not thermal runaway but dead
battery. If someone says LFP cells are just fine to be used without
any electronics.. I would like to see proof of that. So far elevated
heat has destroyed all LiFePO4 cells.

to get bottom of this we have now Tampere Electric Vehicle Center. An
OS project to reveal EVerything about EVs and batteries. There's a
report in Finnish here but you can see some pictures of the place.

This is part of the Ecars. NOW! -community project.


> Also the pre-cursers used to make the anode and cathod are now being
> made with more uniform and regulated structure which helps ward off the
> blocked pores style problems.

Yes. True. And at the same time adding the cost. How much better cells
we need ? 100 Wh/kg and 3000 cycles (70%DOD) are just good. 160wh/kg
and 10000 cycles (80%DOD).. might be already a bit overkill...

> Over charging every time is gonna wear things out, Event he new
> electrolyte can only take so much. I suspect that a full charge once in
> a while helps warm and expand he structure and otherwise get ions
> diffused deeply in and out of the anode and cathode and helps "clean
> them out" before they get permanently plugged up.

over 4000 cycles (100%DOD) were made in continous 1C cycles. That 100%
was between 2 and 4,25 volts. After that there was still about 60% of
the original capacity left.

If that would have been a pack. Say 105 pcs of 40 Ah cells (eCorolla
1.0 set) and linear death curve. ( I know, I know...It's not linear in
real life  :)   but just for fun of it)

105*40*3,2=13441Wh

4000 cycles and down from 100 % to 60 % => 80 % AVG DOD.

=> 10753 Wh * 4000 cycles => 43 011 200 Wh


Say 140 Wh/km (233wh/mi) => 307223 km (183965 mi)

If 1USD/Ah, 105*$40 = $4200

=> $1,37/100km (60mi) or 1€/100km

And this is with HARSH use. Normal driving is not continous and with
full cycles. I would say we can add another 1000-1500 cycles more to
the calculation due that fact.

And energy to move the car: 0,1€/kWh

14kWh/100km => 1,4 €/100km

2,4 €/100km, energy and battery cost.

Looks like we got an ICE killer here. ;)


My point is: We are there already. Batteries are ready. The rest of
the car and systems on board has to be taken there too. Nothing can
stop us anymore.


-akkuJukka

p.s.- It's friday night, kids in bed, silence.. and this is how I have
fun ?   EVDL-junkie :D

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Re: Energy in a TS-LFP100AHA between 3.4-4v

Henry Palonen

Jukka Järvinen kirjoitti 5.2.2010 kello 23.35:
> ...
> to get bottom of this we have now Tampere Electric Vehicle Center. An
> OS project to reveal EVerything about EVs and batteries. There's a
> report in Finnish here but you can see some pictures of the place.
>
> This is part of the Ecars. NOW! -community project.


Good evening from Tampere,

Some pictures and one of the very first cell-measurements (an very old LFP30, no other cells were at hand when I did the measurement-software) can be found from my blog [1].

One purpose of Tampere Electric Vehicle Center is to have actual test-data of how cells behave in different (freezing or near freezing) temperatures. And how they behave with different C-levels at charge/discharge cycle etc. And one big issue here is to get some proven "1:1" test data on different cell brands and BMS-systems. Now we have about 5 BMS-systems on the lab that we can test and few different cell-sizes (more hopefully coming). On top of this "lab"-testing there will be real-life testing done with our conversions. All the results will be freely available, just like our "flag-ship", the eCorolla [2] is an OpenSource EV, these will be OpenSource documents and test-data.

[1] http://randomev.wordpress.com/2010/01/15/at-tevc-15-1-2010/
[2] http://www.ecars-now.org

With very best regards from Tampere / Finland,

Henry "Henkka" Palonen

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Re: Energy in a TS-LFP100AHA between 3.4-4v

Jukka Järvinen-3
Thanks Henkka for the additional info.

I did forgot to put the link down on my reply :)

Here it is:
http://sahkoautoilija.wordpress.com/2010/02/01/tampereen-sahkoautokeskuksen-avajaiset-1-2-2010/

-akkuJukka


2010/2/5 Henry Palonen <[hidden email]>:

>
> Jukka Järvinen kirjoitti 5.2.2010 kello 23.35:
>> ...
>> to get bottom of this we have now Tampere Electric Vehicle Center. An
>> OS project to reveal EVerything about EVs and batteries. There's a
>> report in Finnish here but you can see some pictures of the place.
>>
>> This is part of the Ecars. NOW! -community project.
>
>
> Good evening from Tampere,
>
> Some pictures and one of the very first cell-measurements (an very old LFP30, no other cells were at hand when I did the measurement-software) can be found from my blog [1].
>
> One purpose of Tampere Electric Vehicle Center is to have actual test-data of how cells behave in different (freezing or near freezing) temperatures. And how they behave with different C-levels at charge/discharge cycle etc. And one big issue here is to get some proven "1:1" test data on different cell brands and BMS-systems. Now we have about 5 BMS-systems on the lab that we can test and few different cell-sizes (more hopefully coming). On top of this "lab"-testing there will be real-life testing done with our conversions. All the results will be freely available, just like our "flag-ship", the eCorolla [2] is an OpenSource EV, these will be OpenSource documents and test-data.
>
> [1] http://randomev.wordpress.com/2010/01/15/at-tevc-15-1-2010/
> [2] http://www.ecars-now.org
>
> With very best regards from Tampere / Finland,
>
> Henry "Henkka" Palonen
>
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Re: Energy in a TS-LFP100AHA between 3.4-4v

Charles Whalen
In reply to this post by Henry Palonen
Interesting battery choice you guys made for your conversion projects ...
where you chose TS, from halfway around the world, over EB right there in
your own country.  That's quite an endorsement of TS, and conversely and
more pointedly, not much of one for EB.  Although EB doesn't list any prices
on its website, one could infer from your choice of EB over TS that EB's
price is significantly higher than that of TS, more than is justified by
whatever higher degree of quality EB has over TS.  Or to put it another way,
TS' quality must have substantially and sufficiently improved (over that of
a few years ago) such that the relative quality/price/value trade-off now
favors TS over EB, and EB's batts are not worth the substantially higher
price premium.

CW


On Friday, February 05, 2010 4:57 PM, Henry Palonen wrote:

Jukka Järvinen kirjoitti 5.2.2010 kello 23.35:
> ...
> to get bottom of this we have now Tampere Electric Vehicle Center. An
> OS project to reveal EVerything about EVs and batteries. There's a
> report in Finnish here but you can see some pictures of the place.
>
> This is part of the Ecars. NOW! -community project.


Good evening from Tampere,

Some pictures and one of the very first cell-measurements (an very old
LFP30, no other cells were at hand when I did the measurement-software) can
be found from my blog [1].

One purpose of Tampere Electric Vehicle Center is to have actual test-data
of how cells behave in different (freezing or near freezing) temperatures.
And how they behave with different C-levels at charge/discharge cycle etc.
And one big issue here is to get some proven "1:1" test data on different
cell brands and BMS-systems. Now we have about 5 BMS-systems on the lab that
we can test and few different cell-sizes (more hopefully coming). On top of
this "lab"-testing there will be real-life testing done with our
conversions. All the results will be freely available, just like our
"flag-ship", the eCorolla [2] is an OpenSource EV, these will be OpenSource
documents and test-data.

[1] http://randomev.wordpress.com/2010/01/15/at-tevc-15-1-2010/
[2] http://www.ecars-now.org

With very best regards from Tampere / Finland,

Henry "Henkka" Palonen

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Re: Energy in a TS-LFP100AHA between 3.4-4v

Charles Whalen
In reply to this post by David Nelson-5
Oops, meant to say "your choice of TS over EB", not the other way around
that I said it.  (Should do my proof-reading *before* I hit the "Send"
button, not *after*.)

CW


----- Original Message -----
From: "Charles Whalen" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Saturday, February 13, 2010 11:10 PM
Subject: Re: [EVDL] Energy in a TS-LFP100AHA between 3.4-4v

Interesting battery choice you guys made for your conversion projects ...
where you chose TS, from halfway around the world, over EB right there in
your own country.  That's quite an endorsement of TS, and conversely and
more pointedly, not much of one for EB.  Although EB doesn't list any prices
on its website, one could infer from your choice of EB over TS that EB's
price is significantly higher than that of TS, more than is justified by
whatever higher degree of quality EB has over TS.  Or to put it another way,
TS' quality must have substantially and sufficiently improved (over that of
a few years ago) such that the relative quality/price/value trade-off now
favors TS over EB, and EB's batts are not worth the substantially higher
price premium.

CW


On Friday, February 05, 2010 4:57 PM, Henry Palonen wrote:

Jukka Järvinen kirjoitti 5.2.2010 kello 23.35:
> ...
> to get bottom of this we have now Tampere Electric Vehicle Center. An
> OS project to reveal EVerything about EVs and batteries. There's a
> report in Finnish here but you can see some pictures of the place.
>
> This is part of the Ecars. NOW! -community project.


Good evening from Tampere,

Some pictures and one of the very first cell-measurements (an very old
LFP30, no other cells were at hand when I did the measurement-software) can
be found from my blog [1].

One purpose of Tampere Electric Vehicle Center is to have actual test-data
of how cells behave in different (freezing or near freezing) temperatures.
And how they behave with different C-levels at charge/discharge cycle etc.
And one big issue here is to get some proven "1:1" test data on different
cell brands and BMS-systems. Now we have about 5 BMS-systems on the lab that
we can test and few different cell-sizes (more hopefully coming). On top of
this "lab"-testing there will be real-life testing done with our
conversions. All the results will be freely available, just like our
"flag-ship", the eCorolla [2] is an OpenSource EV, these will be OpenSource
documents and test-data.

[1] http://randomev.wordpress.com/2010/01/15/at-tevc-15-1-2010/
[2] http://www.ecars-now.org

With very best regards from Tampere / Finland,

Henry "Henkka" Palonen

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Re: Energy in a TS-LFP100AHA between 3.4-4v

Peter Gabrielsson
In reply to this post by Charles Whalen
Or perhaps the EB factory is still being constructed, as is plainly
stated on their website....

On Sat, Feb 13, 2010 at 8:10 PM, Charles Whalen <[hidden email]> wrote:

> Interesting battery choice you guys made for your conversion projects ...
> where you chose TS, from halfway around the world, over EB right there in
> your own country.  That's quite an endorsement of TS, and conversely and
> more pointedly, not much of one for EB.  Although EB doesn't list any prices
> on its website, one could infer from your choice of EB over TS that EB's
> price is significantly higher than that of TS, more than is justified by
> whatever higher degree of quality EB has over TS.  Or to put it another way,
> TS' quality must have substantially and sufficiently improved (over that of
> a few years ago) such that the relative quality/price/value trade-off now
> favors TS over EB, and EB's batts are not worth the substantially higher
> price premium.
>
> CW
>
>
> On Friday, February 05, 2010 4:57 PM, Henry Palonen wrote:
>
> Jukka Järvinen kirjoitti 5.2.2010 kello 23.35:
>> ...
>> to get bottom of this we have now Tampere Electric Vehicle Center. An
>> OS project to reveal EVerything about EVs and batteries. There's a
>> report in Finnish here but you can see some pictures of the place.
>>
>> This is part of the Ecars. NOW! -community project.
>
>
> Good evening from Tampere,
>
> Some pictures and one of the very first cell-measurements (an very old
> LFP30, no other cells were at hand when I did the measurement-software) can
> be found from my blog [1].
>
> One purpose of Tampere Electric Vehicle Center is to have actual test-data
> of how cells behave in different (freezing or near freezing) temperatures.
> And how they behave with different C-levels at charge/discharge cycle etc.
> And one big issue here is to get some proven "1:1" test data on different
> cell brands and BMS-systems. Now we have about 5 BMS-systems on the lab that
> we can test and few different cell-sizes (more hopefully coming). On top of
> this "lab"-testing there will be real-life testing done with our
> conversions. All the results will be freely available, just like our
> "flag-ship", the eCorolla [2] is an OpenSource EV, these will be OpenSource
> documents and test-data.
>
> [1] http://randomev.wordpress.com/2010/01/15/at-tevc-15-1-2010/
> [2] http://www.ecars-now.org
>
> With very best regards from Tampere / Finland,
>
> Henry "Henkka" Palonen
>
> _______________________________________________
> General support: http://evdl.org/help/
> Unsubscribe: http://www.evdl.org/help/index.html#usub
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archive / Forum: http://evdl.org/archive/
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>
>



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Re: Energy in a TS-LFP100AHA between 3.4-4v

Charles Whalen
Also says they've been in business making batts since 2003.  So that new
factory construction is apparently an expansion of their facilities.


----- Original Message -----
From: "Peter Gabrielsson" <[hidden email]>
To: "Charles Whalen" <[hidden email]>; "Electric Vehicle Discussion
List" <[hidden email]>
Sent: Saturday, February 13, 2010 11:28 PM
Subject: Re: [EVDL] Energy in a TS-LFP100AHA between 3.4-4v

Or perhaps the EB factory is still being constructed, as is plainly
stated on their website....

On Sat, Feb 13, 2010 at 8:10 PM, Charles Whalen <[hidden email]>
wrote:

> Interesting battery choice you guys made for your conversion projects ...
> where you chose TS, from halfway around the world, over EB right there in
> your own country. That's quite an endorsement of TS, and conversely and
> more pointedly, not much of one for EB. Although EB doesn't list any
> prices
> on its website, one could infer from your choice of EB over TS that EB's
> price is significantly higher than that of TS, more than is justified by
> whatever higher degree of quality EB has over TS. Or to put it another
> way,
> TS' quality must have substantially and sufficiently improved (over that
> of
> a few years ago) such that the relative quality/price/value trade-off now
> favors TS over EB, and EB's batts are not worth the substantially higher
> price premium.
>
> CW
>
>
> On Friday, February 05, 2010 4:57 PM, Henry Palonen wrote:
>
> Jukka Järvinen kirjoitti 5.2.2010 kello 23.35:
>> ...
>> to get bottom of this we have now Tampere Electric Vehicle Center. An
>> OS project to reveal EVerything about EVs and batteries. There's a
>> report in Finnish here but you can see some pictures of the place.
>>
>> This is part of the Ecars. NOW! -community project.
>
>
> Good evening from Tampere,
>
> Some pictures and one of the very first cell-measurements (an very old
> LFP30, no other cells were at hand when I did the measurement-software)
> can
> be found from my blog [1].
>
> One purpose of Tampere Electric Vehicle Center is to have actual test-data
> of how cells behave in different (freezing or near freezing) temperatures.
> And how they behave with different C-levels at charge/discharge cycle etc.
> And one big issue here is to get some proven "1:1" test data on different
> cell brands and BMS-systems. Now we have about 5 BMS-systems on the lab
> that
> we can test and few different cell-sizes (more hopefully coming). On top
> of
> this "lab"-testing there will be real-life testing done with our
> conversions. All the results will be freely available, just like our
> "flag-ship", the eCorolla [2] is an OpenSource EV, these will be
> OpenSource
> documents and test-data.
>
> [1] http://randomev.wordpress.com/2010/01/15/at-tevc-15-1-2010/
> [2] http://www.ecars-now.org
>
> With very best regards from Tampere / Finland,
>
> Henry "Henkka" Palonen
>
> _______________________________________________
> General support: http://evdl.org/help/
> Unsubscribe: http://www.evdl.org/help/index.html#usub
> Usage guidelines: http://evdl.org/help/index.html#conv
> Archive / Forum: http://evdl.org/archive/
> Subscription options: http://lists.sjsu.edu/mailman/listinfo/ev
>
>



--
www.electric-lemon.com

_______________________________________________
General support: http://evdl.org/help/
Unsubscribe: http://www.evdl.org/help/index.html#usub
Usage guidelines: http://evdl.org/help/index.html#conv
Archive / Forum: http://evdl.org/archive/
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