replacement or removal of suspected bad 40Ah prismatic LiFePO4 battery

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replacement or removal of suspected bad 40Ah prismatic LiFePO4 battery

mnevans
I'm new to this discussion list, so I ask your patience: my understanding of EV systems and Li-ion batteries is limited.

The question is: replace a bad battery in a pack of 19, or make the pack 2 batteries smaller and suffer an unknown loss of voltage and range?

Background:
 
I think I have a bad battery in one of 19 batteries that is in the second bank of a 4 bank x 19 CALB CA40FI battery pack.  The battery pack is used in a 10KW battery that is part of a Plug-In Supply conversion of a 2004 Prius to a plug-in Prius.  Robb Protheroe installed the system in late 2014, and it has seen about 10K miles, maybe 60% of that in all electric mode, about 900 partial or full charge cycles.  

The evidence that the battery is bad is an incomplete loop circuit.  I found that the battery management board atop the suspect battery was not powered, and moving that BMS board to another battery adjacent powered it.    The suspect battery was at 2.67V.  The others adjacent are at 3.0V.  Originally they were all balanced at 3.26-3.27V.

Robb Protheroe at Plug-In Supply suggested replacing the battery with a new one.  Unfortunately CALB no longer makes this 40Ah battery, but the Sinopoly or Winston 40Ah prismatic cells are nearly the same dimensions and specifications.  It looks like I can get a replacement for about USD$60  including shipping to me in Maryland USA, using www.ev-power.eu (a US supplier wanted $42 shipping for a $55 cell).  

The other option is to remove the bad battery and the one adjacent, and carry on with a lower voltage pack.  Robb is unsure whether the range loss would be proportional (7%, I can live with that), or more, due to "voltage sag" and age of cells.  He suggested I ask you, so here I am.

Questions:

1. Would you recommend replacing or removing batteries from my pack?

2. If removing, what is your guess on loss of range due to lower pack V, voltage sag?

3. If replacing, do you expect the new cell to assume the lifetime of the rest of the batteries in the pack, as others have written on this listserv?

So far I am thinking to try removing, see how the range is affected by testing on a known route that is longer than the original hybrid range with this pack installed.  If unacceptably worse, add back the replacement cell.  If not, carry on with the slightly smaller battery pack.  But I would be grateful for the wisdom of the list.

Thank you in advance for your help,
Mike

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Re: replacement or removal of suspected bad 40Ah prismatic LiFePO4 battery

Electric Vehicle Discussion List mailing list
For $60, I'd just replace it.  I don't know anything about the "Plug-In
Supply" conversion system, or how a lower voltage will affect anything
else in the car.

The replacement cell will (presumably) have more capacity than your
original ones, but assuming that the current loop cuts out the charger
when the smallest capacity cell is "full" this shouldn't pose a problem,
you just won't be taking full advantage of it's newer/larger capacity.

Jay

On 08/03/2017 04:34 PM, mnevans via EV wrote:

> I'm new to this discussion list, so I ask your patience: my understanding of
> EV systems and Li-ion batteries is limited.
>
> The question is: replace a bad battery in a pack of 19, or make the pack 2
> batteries smaller and suffer an unknown loss of voltage and range?
>
> Background:
>    
> I think I have a bad battery in one of 19 batteries that is in the second
> bank of a 4 bank x 19 CALB CA40FI battery pack.  The battery pack is used in
> a 10KW battery that is part of a Plug-In Supply conversion of a 2004 Prius
> to a plug-in Prius.  Robb Protheroe installed the system in late 2014, and
> it has seen about 10K miles, maybe 60% of that in all electric mode, about
> 900 partial or full charge cycles.
>
> The evidence that the battery is bad is an incomplete loop circuit.  I found
> that the battery management board atop the suspect battery was not powered,
> and moving that BMS board to another battery adjacent powered it.    The
> suspect battery was at 2.67V.  The others adjacent are at 3.0V.  Originally
> they were all balanced at 3.26-3.27V.
>
> Robb Protheroe at Plug-In Supply suggested replacing the battery with a new
> one.  Unfortunately CALB no longer makes this 40Ah battery, but the Sinopoly
> or Winston 40Ah prismatic cells are nearly the same dimensions and
> specifications.  It looks like I can get a replacement for about USD$60
> including shipping to me in Maryland USA, using www.ev-power.eu (a US
> supplier wanted $42 shipping for a $55 cell).
>
> The other option is to remove the bad battery and the one adjacent, and
> carry on with a lower voltage pack.  Robb is unsure whether the range loss
> would be proportional (7%, I can live with that), or more, due to "voltage
> sag" and age of cells.  He suggested I ask you, so here I am.
>
> Questions:
>
> 1. Would you recommend replacing or removing batteries from my pack?
>
> 2. If removing, what is your guess on loss of range due to lower pack V,
> voltage sag?
>
> 3. If replacing, do you expect the new cell to assume the lifetime of the
> rest of the batteries in the pack, as others have written on this listserv?
>
> So far I am thinking to try removing, see how the range is affected by
> testing on a known route that is longer than the original hybrid range with
> this pack installed.  If unacceptably worse, add back the replacement cell.
> If not, carry on with the slightly smaller battery pack.  But I would be
> grateful for the wisdom of the list.
>
> Thank you in advance for your help,
> Mike
>
>
>
> --
> View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/replacement-or-removal-of-suspected-bad-40Ah-prismatic-LiFePO4-battery-tp4687552.html
> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.
> _______________________________________________
> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> http://lists.evdl.org/listinfo.cgi/ev-evdl.org
> Read EVAngel's EV News at http://evdl.org/evln/
> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
>
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Re: replacement or removal of suspected bad 40Ah prismatic LiFePO4 battery

Electric Vehicle Discussion List mailing list
Should have bought a Volt!  The 2013-2014 can be purchased for 11-13K$  My 2014 had 51k miles and I bought it for 11.8K.I'm not trying to be a jerk for mentioning this and understand your technical issues, I still own 2 2000 Honda Insight's that I needto figure out what I should do, sell or convert.  I plan on converting one of them, but the Chevy Volt is a luxury vehicle that drivesbetter than any car I've owned.  I drive primarily on electric only, but the gas backup is nice.  I plan on converting one of the Insights as a projectand I love those cars, but the ride is like a rickshaw compared to the Volt.
 

    On Thursday, August 3, 2017 10:22 PM, Jay Summet via EV <[hidden email]> wrote:
 

 For $60, I'd just replace it.  I don't know anything about the "Plug-In
Supply" conversion system, or how a lower voltage will affect anything
else in the car.

The replacement cell will (presumably) have more capacity than your
original ones, but assuming that the current loop cuts out the charger
when the smallest capacity cell is "full" this shouldn't pose a problem,
you just won't be taking full advantage of it's newer/larger capacity.

Jay

On 08/03/2017 04:34 PM, mnevans via EV wrote:

> I'm new to this discussion list, so I ask your patience: my understanding of
> EV systems and Li-ion batteries is limited.
>
> The question is: replace a bad battery in a pack of 19, or make the pack 2
> batteries smaller and suffer an unknown loss of voltage and range?
>
> Background:
>   
> I think I have a bad battery in one of 19 batteries that is in the second
> bank of a 4 bank x 19 CALB CA40FI battery pack.  The battery pack is used in
> a 10KW battery that is part of a Plug-In Supply conversion of a 2004 Prius
> to a plug-in Prius.  Robb Protheroe installed the system in late 2014, and
> it has seen about 10K miles, maybe 60% of that in all electric mode, about
> 900 partial or full charge cycles.
>
> The evidence that the battery is bad is an incomplete loop circuit.  I found
> that the battery management board atop the suspect battery was not powered,
> and moving that BMS board to another battery adjacent powered it.    The
> suspect battery was at 2.67V.  The others adjacent are at 3.0V.  Originally
> they were all balanced at 3.26-3.27V.
>
> Robb Protheroe at Plug-In Supply suggested replacing the battery with a new
> one.  Unfortunately CALB no longer makes this 40Ah battery, but the Sinopoly
> or Winston 40Ah prismatic cells are nearly the same dimensions and
> specifications.  It looks like I can get a replacement for about USD$60
> including shipping to me in Maryland USA, using www.ev-power.eu (a US
> supplier wanted $42 shipping for a $55 cell).
>
> The other option is to remove the bad battery and the one adjacent, and
> carry on with a lower voltage pack.  Robb is unsure whether the range loss
> would be proportional (7%, I can live with that), or more, due to "voltage
> sag" and age of cells.  He suggested I ask you, so here I am.
>
> Questions:
>
> 1. Would you recommend replacing or removing batteries from my pack?
>
> 2. If removing, what is your guess on loss of range due to lower pack V,
> voltage sag?
>
> 3. If replacing, do you expect the new cell to assume the lifetime of the
> rest of the batteries in the pack, as others have written on this listserv?
>
> So far I am thinking to try removing, see how the range is affected by
> testing on a known route that is longer than the original hybrid range with
> this pack installed.  If unacceptably worse, add back the replacement cell.
> If not, carry on with the slightly smaller battery pack.  But I would be
> grateful for the wisdom of the list.
>
> Thank you in advance for your help,
> Mike
>
>
>
> --
> View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/replacement-or-removal-of-suspected-bad-40Ah-prismatic-LiFePO4-battery-tp4687552.html
> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.
> _______________________________________________
> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> http://lists.evdl.org/listinfo.cgi/ev-evdl.org
> Read EVAngel's EV News at http://evdl.org/evln/
> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
>
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Re: replacement or removal of suspected bad 40Ah prismatic LiFePO4 battery

Electric Vehicle Discussion List mailing list
In reply to this post by mnevans
It's very easy to test a battery. Take it out of the pack and try to charge it. It will rise in voltage or not. You BMS boards probably have a minimum voltage to operate and cell fell below that voltage and does not imply the cells is bad. After you charge it then hook up to a know load and measure the capacity of the cell.

Sent from my iPhone

> On Aug 3, 2017, at 3:34 PM, mnevans via EV <[hidden email]> wrote:
>
> I'm new to this discussion list, so I ask your patience: my understanding of
> EV systems and Li-ion batteries is limited.
>
> The question is: replace a bad battery in a pack of 19, or make the pack 2
> batteries smaller and suffer an unknown loss of voltage and range?
>
> Background:
>
> I think I have a bad battery in one of 19 batteries that is in the second
> bank of a 4 bank x 19 CALB CA40FI battery pack.  The battery pack is used in
> a 10KW battery that is part of a Plug-In Supply conversion of a 2004 Prius
> to a plug-in Prius.  Robb Protheroe installed the system in late 2014, and
> it has seen about 10K miles, maybe 60% of that in all electric mode, about
> 900 partial or full charge cycles.  
>
> The evidence that the battery is bad is an incomplete loop circuit.  I found
> that the battery management board atop the suspect battery was not powered,
> and moving that BMS board to another battery adjacent powered it.    The
> suspect battery was at 2.67V.  The others adjacent are at 3.0V.  Originally
> they were all balanced at 3.26-3.27V.
>
> Robb Protheroe at Plug-In Supply suggested replacing the battery with a new
> one.  Unfortunately CALB no longer makes this 40Ah battery, but the Sinopoly
> or Winston 40Ah prismatic cells are nearly the same dimensions and
> specifications.  It looks like I can get a replacement for about USD$60
> including shipping to me in Maryland USA, using www.ev-power.eu (a US
> supplier wanted $42 shipping for a $55 cell).  
>
> The other option is to remove the bad battery and the one adjacent, and
> carry on with a lower voltage pack.  Robb is unsure whether the range loss
> would be proportional (7%, I can live with that), or more, due to "voltage
> sag" and age of cells.  He suggested I ask you, so here I am.
>
> Questions:
>
> 1. Would you recommend replacing or removing batteries from my pack?
>
> 2. If removing, what is your guess on loss of range due to lower pack V,
> voltage sag?
>
> 3. If replacing, do you expect the new cell to assume the lifetime of the
> rest of the batteries in the pack, as others have written on this listserv?
>
> So far I am thinking to try removing, see how the range is affected by
> testing on a known route that is longer than the original hybrid range with
> this pack installed.  If unacceptably worse, add back the replacement cell.
> If not, carry on with the slightly smaller battery pack.  But I would be
> grateful for the wisdom of the list.
>
> Thank you in advance for your help,
> Mike
>
>
>
> --
> View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/replacement-or-removal-of-suspected-bad-40Ah-prismatic-LiFePO4-battery-tp4687552.html
> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.
> _______________________________________________
> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> http://lists.evdl.org/listinfo.cgi/ev-evdl.org
> Read EVAngel's EV News at http://evdl.org/evln/
> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
>

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Re: replacement or removal of suspected bad 40Ah prismatic LiFePO4 battery

Electric Vehicle Discussion List mailing list
In reply to this post by mnevans


3.00V is considered dead. 2.67V is really dead. Your pack is only as
good as the weakest (lowest capacity) cell.
Unfortunately we don't know anything about the BMS system.
I would guess that the electronics consists of a DC to DC converter.
Either the converter (or the BMS) may not work properly (or at all) with
a lower voltage pack.
I would replace the cell and make sure there aren't any other duds in
the pack.

Al



> Questions:
>
> 1. Would you recommend replacing or removing batteries from my pack?
>
> 2. If removing, what is your guess on loss of range due to lower pack V,
> voltage sag?
>
> 3. If replacing, do you expect the new cell to assume the lifetime of the
> rest of the batteries in the pack, as others have written on this listserv?
>
> So far I am thinking to try removing, see how the range is affected by
> testing on a known route that is longer than the original hybrid range with
> this pack installed.  If unacceptably worse, add back the replacement cell.
> If not, carry on with the slightly smaller battery pack.  But I would be
> grateful for the wisdom of the list.
>
> Thank you in advance for your help,
> Mike
>
>
>
> --
> View this message in context: http://electric-vehicle-discussion-list.413529.n4.nabble.com/replacement-or-removal-of-suspected-bad-40Ah-prismatic-LiFePO4-battery-tp4687552.html
> Sent from the Electric Vehicle Discussion List mailing list archive at Nabble.com.
> _______________________________________________
> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> http://lists.evdl.org/listinfo.cgi/ev-evdl.org
> Read EVAngel's EV News at http://evdl.org/evln/
> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
>
>

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Re: replacement or removal of suspected bad 40Ah prismatic LiFePO4 battery

mnevans
In reply to this post by mnevans
Thanks to everyone for their kind and rapid responses.  

I think I'm going to take the advice to replace the battery with a similar Sinopoly for $60.  That was Robb's suggestion too.

I can try charging the battery within the pack, bypassing the BMS circuitry, but it doesn't charge.  

I haven't tried isolating and charging that one suspect battery b/c I don't have a charger.

The battery pack is flat because the failure occurred when the battery was discharged (according to the BMSes) and their controller.  I think (hope) I should be able to charge it once the bad battery is replaced.

I haven't tried buying a used Volt, because I can't time travel back to 2014. ;-)

-Mike
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Re: replacement or removal of suspected bad 40Ah prismatic LiFePO4 battery

tomw
3.0V is not at all considered dead for a CALB LiFePO4 cell. Nominal, or average voltage is 3.2V, 20% discharged would be at about 2.4-2.6V. Max recommended voltage is 3.6V.  I've been using a CALB pack for 8 years, and routinely drive the cells down to below 3.0V.
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