Re: [EVDL] balancing: ?PD.lu purposely maintenance-drain Tesla-S pack every 20, 000km?
Some people may also be getting confused with bottom-balancing, which some
EV builders do. But that is only done one time, at the start of putting
together a battery pack, and typically of used cells, to get them to
duscharge to be fairly balanced at the end of driving. But this is not the
technique of IEMs if they don't want to damage the pack
-Ed Thorpe
On Tue, Jul 2, 2019, 6:18 AM Peri Hartman via EV wrote:
> What would be cool is if the EVSE had a "recalibrate" mode where it
> first fed power back to the grid and then recharged the EV.
>
> -- Original Message --
> From: "Peri Hartman"
> To: "Electric Vehicle Discussion List"
> Sent: 02-Jul-19 6:17:13 AM
> Subject: Re[2]: [EVDL] balancing: ?PD.lu purposely maintenance-drain
> Tesla-S pack every 20, 000km?
>
> >Ah, that makes more sense. Thus, every time I fully charge, I am
> balancing the cells. That's what I've been assuming.
> >
> >To calculate the Wh, though, does one really have to fully discharge ? I
> guess, no matter how accurately it can measure current out of and current
> into the battery, cumulative errors will appear. But fully discharging an
> EV battery is difficult ! How do you do it - leave it in the driveway with
> the heater running full ?
> >
> >Peri
> >
> >-- Original Message --
> >From: "paul dove via EV"
> >To: ev@lists.evdl.org
> >Cc: "paul dove" ; "brucedp5"
> >Sent: 01-Jul-19 8:24:42 AM
> >Subject: Re: [EVDL] balancing: ?PD.lu purposely maintenance-drain Tesla-S
> pack every 20, 000km?
> >
> >>I think people get confused with the term balancing. It is pretty much a
> carry over from lead acid batteries where the take all the cells to boiling
> to get them to the same voltage at the end of charge. It doesn't apply to
> Lithium since this is derogatory to cell life.
> >>I believe what people are experiencing is the algorithm built into the
> system that keeps up with capacity from all the data, current, voltage,
> sag, internal resistance, temperature after a while of short
> discharges and charges the capacity value can get off from actual battery
> capacity and it gets corrected when you do a deeper discharge.
> >>If any balancing is going on it happens every time you charge... most
> likely or when close to fully charged. Maybe some guys who actual take cell
> data can shed some light on this but I don't think this is affecting
> capacity much.
> >>
> >>
> >> On Saturday, June 29, 2019, 5:44:55 PM CDT, brucedp5 via EV <
> ev@lists.evdl.org> wrote:
> >>
> >> It took some digging, but I found a EVLN post I made back in Aug 2015
> that
> >>might shed some light on this topic, see
> >>
> >>
> http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-Offset-Supercharging-degradation-with-pack-balancing-tp4677028.html
> >> ... Lost capacity may be restored by “balancing the pack”—that is,
> charging
> >>it to 100 percent to make sure that each of the cells is fully topped
> off.
> >>
> >>Tesla, of course, is mum on the subject; I’ve never seen any official
> word
> >>on pack balancing, and the company officially recommends against
> charging to
> >>100 percent unless maximum range is necessary.
> >>
> >>The Model S fan site Teslarati, however, recommends charging the pack to
> >>100 percent every three months or so.
> >>
> >>When I asked at my local Tesla Service Center about “pack balancing”, I
> was
> >>told they did it all the time.
> >>
> >>“Discharge it as close as you can to zero, and then charge it as slow as
> >>possible all the way up to 100 percent,” I was told. “You’ll probably get
> >>some capacity back.”
> >>
> >>It works!
> >> ...
> >>
> >> and comments on this topic are shown on:
> >>
> http://electric-vehicle-discussion-list.413529.n4.nabble.com/template/NamlServlet.jtp?macro=search_page=413529=tesla+pack+balancing=0
> >>
> >>
> >>
> >>
> >>For EVLN EV-newswire posts use:
> >> http://evdl.org/archive/
> >>
> >>
> >>{brucedp.neocities.org}
> >>
> >>--
> >>Sent from: http://electric-vehicle-discussion-list.413529.n4.nabble.com/
> >>___
> >>UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
> >>http://lists.evdl.org/listinfo.cgi/ev-evdl.org
> >>Please discuss EV drag racing at NEDRA (
> http://groups.yahoo.com/group/NED
Re: [EVDL] balancing: ?PD.lu purposely maintenance-drain Tesla-S pack every 20, 000km?
What would be cool is if the EVSE had a "recalibrate" mode where it
first fed power back to the grid and then recharged the EV.
-- Original Message --
From: "Peri Hartman"
To: "Electric Vehicle Discussion List"
Sent: 02-Jul-19 6:17:13 AM
Subject: Re[2]: [EVDL] balancing: ?PD.lu purposely maintenance-drain
Tesla-S pack every 20, 000km?
Ah, that makes more sense. Thus, every time I fully charge, I am balancing the
cells. That's what I've been assuming.
To calculate the Wh, though, does one really have to fully discharge ? I guess,
no matter how accurately it can measure current out of and current into the
battery, cumulative errors will appear. But fully discharging an EV battery is
difficult ! How do you do it - leave it in the driveway with the heater
running full ?
Peri
-- Original Message --
From: "paul dove via EV"
To: ev@lists.evdl.org
Cc: "paul dove" ; "brucedp5"
Sent: 01-Jul-19 8:24:42 AM
Subject: Re: [EVDL] balancing: ?PD.lu purposely maintenance-drain Tesla-S pack
every 20, 000km?
I think people get confused with the term balancing. It is pretty much a carry
over from lead acid batteries where the take all the cells to boiling to get
them to the same voltage at the end of charge. It doesn't apply to Lithium
since this is derogatory to cell life.
I believe what people are experiencing is the algorithm built into the system
that keeps up with capacity from all the data, current, voltage, sag, internal
resistance, temperature after a while of short discharges and charges
the capacity value can get off from actual battery capacity and it gets
corrected when you do a deeper discharge.
If any balancing is going on it happens every time you charge... most likely or
when close to fully charged. Maybe some guys who actual take cell data can shed
some light on this but I don't think this is affecting capacity much.
On Saturday, June 29, 2019, 5:44:55 PM CDT, brucedp5 via EV
wrote:
It took some digging, but I found a EVLN post I made back in Aug 2015 that
might shed some light on this topic, see
http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-Offset-Supercharging-degradation-with-pack-balancing-tp4677028.html
... Lost capacity may be restored by “balancing the pack”—that is, charging
it to 100 percent to make sure that each of the cells is fully topped off.
Tesla, of course, is mum on the subject; I’ve never seen any official word
on pack balancing, and the company officially recommends against charging to
100 percent unless maximum range is necessary.
The Model S fan site Teslarati, however, recommends charging the pack to
100 percent every three months or so.
When I asked at my local Tesla Service Center about “pack balancing”, I was
told they did it all the time.
“Discharge it as close as you can to zero, and then charge it as slow as
possible all the way up to 100 percent,” I was told. “You’ll probably get
some capacity back.”
It works!
...
and comments on this topic are shown on:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/template/NamlServlet.jtp?macro=search_page=413529=tesla+pack+balancing=0
For EVLN EV-newswire posts use:
http://evdl.org/archive/
{brucedp.neocities.org}
--
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Re: [EVDL] balancing: ?PD.lu purposely maintenance-drain Tesla-S pack every 20, 000km?
Ah, that makes more sense. Thus, every time I fully charge, I am
balancing the cells. That's what I've been assuming.
To calculate the Wh, though, does one really have to fully discharge ? I
guess, no matter how accurately it can measure current out of and
current into the battery, cumulative errors will appear. But fully
discharging an EV battery is difficult ! How do you do it - leave it in
the driveway with the heater running full ?
Peri
-- Original Message --
From: "paul dove via EV"
To: ev@lists.evdl.org
Cc: "paul dove" ; "brucedp5"
Sent: 01-Jul-19 8:24:42 AM
Subject: Re: [EVDL] balancing: ?PD.lu purposely maintenance-drain
Tesla-S pack every 20, 000km?
I think people get confused with the term balancing. It is pretty much a carry
over from lead acid batteries where the take all the cells to boiling to get
them to the same voltage at the end of charge. It doesn't apply to Lithium
since this is derogatory to cell life.
I believe what people are experiencing is the algorithm built into the system
that keeps up with capacity from all the data, current, voltage, sag, internal
resistance, temperature after a while of short discharges and charges
the capacity value can get off from actual battery capacity and it gets
corrected when you do a deeper discharge.
If any balancing is going on it happens every time you charge... most likely or
when close to fully charged. Maybe some guys who actual take cell data can shed
some light on this but I don't think this is affecting capacity much.
On Saturday, June 29, 2019, 5:44:55 PM CDT, brucedp5 via EV
wrote:
It took some digging, but I found a EVLN post I made back in Aug 2015 that
might shed some light on this topic, see
http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-Offset-Supercharging-degradation-with-pack-balancing-tp4677028.html
... Lost capacity may be restored by “balancing the pack”—that is, charging
it to 100 percent to make sure that each of the cells is fully topped off.
Tesla, of course, is mum on the subject; I’ve never seen any official word
on pack balancing, and the company officially recommends against charging to
100 percent unless maximum range is necessary.
The Model S fan site Teslarati, however, recommends charging the pack to
100 percent every three months or so.
When I asked at my local Tesla Service Center about “pack balancing”, I was
told they did it all the time.
“Discharge it as close as you can to zero, and then charge it as slow as
possible all the way up to 100 percent,” I was told. “You’ll probably get
some capacity back.”
It works!
...
and comments on this topic are shown on:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/template/NamlServlet.jtp?macro=search_page=413529=tesla+pack+balancing=0
For EVLN EV-newswire posts use:
http://evdl.org/archive/
{brucedp.neocities.org}
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Re: [EVDL] balancing: ?PD.lu purposely maintenance-drain Tesla-S pack every 20, 000km?
I agree that it is not good to satisfy some firmware deficiency by putting a very deep cycle on your pack. Best to correct the firmware, or ignore the problem. On 7/2/2019 7:41 PM, EVDL Administrator via EV wrote: On 1 Jul 2019 at 15:24, paul dove via EV wrote: I think people get confused with the term balancing. It is pretty much a carry over from lead acid batteries where the take all the cells to boiling to get them to the same voltage at the end of charge. That's what I'd call equalization -- forcing current through already-charged cells or batteries, overcharging them, in order to fully charge others that aren't yet. Balancing lead batteries is different from equalization, and similar to balancing any other cell or battery. I'm not an expert, but from what I can tell, regardless of the chemistry, balancing cells or batteries in series usually involves either bypassing charging current around full cells or modules, or actively using other cells/modules to charge the cells/modules with lower charge levels. The goal of balancing shouldn't be so much to get all cells/modules to the same voltage, but rather to get them to the same state of charge (usually full). But generally voltage and SOC are considered congruent for balancing purposes, even though they're not really. As for periodic deliberate deep discharges, again, I'm not an electrochemist or anything, but my understanding is that it's not all that healthy for most batteries. (NiCd is an exception, apparently, but only if you're careful not to reverse them.) I suspect that when a discharge to or near 0 SOC seems to increase capacity, it's actually because it's somehow recalibrating the firmware that manages the battery. The capacity is still there, it's just that the BMS doesn't think it is. Running the battery flat, or nearly so, sort of reboots or recalibrates the BMS. I own a netbook that "finds" some capacity that it's "lost" when I do this. But I don't like it. I just don't think that's how you treat a battery if you want to show it you like it. David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] balancing: ?PD.lu purposely maintenance-drain Tesla-S pack every 20, 000km?
On 1 Jul 2019 at 15:24, paul dove via EV wrote: > I think people get confused with the term balancing. It is pretty much a carry > over from lead acid batteries where the take all the cells to boiling to get > them to the same voltage at the end of charge. That's what I'd call equalization -- forcing current through already-charged cells or batteries, overcharging them, in order to fully charge others that aren't yet. Balancing lead batteries is different from equalization, and similar to balancing any other cell or battery. I'm not an expert, but from what I can tell, regardless of the chemistry, balancing cells or batteries in series usually involves either bypassing charging current around full cells or modules, or actively using other cells/modules to charge the cells/modules with lower charge levels. The goal of balancing shouldn't be so much to get all cells/modules to the same voltage, but rather to get them to the same state of charge (usually full). But generally voltage and SOC are considered congruent for balancing purposes, even though they're not really. As for periodic deliberate deep discharges, again, I'm not an electrochemist or anything, but my understanding is that it's not all that healthy for most batteries. (NiCd is an exception, apparently, but only if you're careful not to reverse them.) I suspect that when a discharge to or near 0 SOC seems to increase capacity, it's actually because it's somehow recalibrating the firmware that manages the battery. The capacity is still there, it's just that the BMS doesn't think it is. Running the battery flat, or nearly so, sort of reboots or recalibrates the BMS. I own a netbook that "finds" some capacity that it's "lost" when I do this. But I don't like it. I just don't think that's how you treat a battery if you want to show it you like it. David Roden - Akron, Ohio, USA EVDL Administrator = = = = = = = = = = = = = = = = = = = = = = = = = = = = = EVDL Information: http://www.evdl.org/help/ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = Note: mail sent to "evpost" and "etpost" addresses will not reach me. To send a private message, please obtain my email address from the webpage http://www.evdl.org/help/ . = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ___ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
Re: [EVDL] balancing: ?PD.lu purposely maintenance-drain Tesla-S pack every 20, 000km?
I think people get confused with the term balancing. It is pretty much a carry
over from lead acid batteries where the take all the cells to boiling to get
them to the same voltage at the end of charge. It doesn't apply to Lithium
since this is derogatory to cell life.
I believe what people are experiencing is the algorithm built into the system
that keeps up with capacity from all the data, current, voltage, sag, internal
resistance, temperature after a while of short discharges and charges
the capacity value can get off from actual battery capacity and it gets
corrected when you do a deeper discharge.
If any balancing is going on it happens every time you charge... most likely or
when close to fully charged. Maybe some guys who actual take cell data can shed
some light on this but I don't think this is affecting capacity much.
On Saturday, June 29, 2019, 5:44:55 PM CDT, brucedp5 via EV
wrote:
It took some digging, but I found a EVLN post I made back in Aug 2015 that
might shed some light on this topic, see
http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-Offset-Supercharging-degradation-with-pack-balancing-tp4677028.html
... Lost capacity may be restored by “balancing the pack”—that is, charging
it to 100 percent to make sure that each of the cells is fully topped off.
Tesla, of course, is mum on the subject; I’ve never seen any official word
on pack balancing, and the company officially recommends against charging to
100 percent unless maximum range is necessary.
The Model S fan site Teslarati, however, recommends charging the pack to
100 percent every three months or so.
When I asked at my local Tesla Service Center about “pack balancing”, I was
told they did it all the time.
“Discharge it as close as you can to zero, and then charge it as slow as
possible all the way up to 100 percent,” I was told. “You’ll probably get
some capacity back.”
It works!
...
and comments on this topic are shown on:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/template/NamlServlet.jtp?macro=search_page=413529=tesla+pack+balancing=0
For EVLN EV-newswire posts use:
http://evdl.org/archive/
{brucedp.neocities.org}
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[EVDL] balancing: ?PD.lu purposely maintenance-drain Tesla-S pack every 20, 000km?
It took some digging, but I found a EVLN post I made back in Aug 2015 that
might shed some light on this topic, see
http://electric-vehicle-discussion-list.413529.n4.nabble.com/EVLN-Offset-Supercharging-degradation-with-pack-balancing-tp4677028.html
... Lost capacity may be restored by “balancing the pack”—that is, charging
it to 100 percent to make sure that each of the cells is fully topped off.
Tesla, of course, is mum on the subject; I’ve never seen any official word
on pack balancing, and the company officially recommends against charging to
100 percent unless maximum range is necessary.
The Model S fan site Teslarati, however, recommends charging the pack to
100 percent every three months or so.
When I asked at my local Tesla Service Center about “pack balancing”, I was
told they did it all the time.
“Discharge it as close as you can to zero, and then charge it as slow as
possible all the way up to 100 percent,” I was told. “You’ll probably get
some capacity back.”
It works!
...
and comments on this topic are shown on:
http://electric-vehicle-discussion-list.413529.n4.nabble.com/template/NamlServlet.jtp?macro=search_page=413529=tesla+pack+balancing=0
For EVLN EV-newswire posts use:
http://evdl.org/archive/
{brucedp.neocities.org}
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