EVLN: EV packs optimized 4longevity, Phone Batteries 4co$t

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EVLN: EV packs optimized 4longevity, Phone Batteries 4co$t

Electric Vehicle Discussion List mailing list


https://incompliancemag.com/article/why-mobile-phone-batteries-do-not-last-as-long-as-an-ev-battery/
Why Mobile Phone Batteries Do Not Last as Long as an EV Battery
March 30, 2018  Isidor Buchman

[images  
https://incompliancemag.com/wp-content/uploads/2018/03/1804_F2_fig1.png

https://incompliancemag.com/wp-content/uploads/2018/03/1804_F2_fig2.png
]

How Usage and Management Affect Longevity

Car makers are extending the driving range of the electric vehicle to
resemble a gasoline-powered car. This requires larger batteries that grow
exponentially with the distance driven. Figure 1 illustrates the estimated
driving ranges with different battery systems and hydrogen as a function of
size.
Figure 1: Battery size as a function of driving range
Oversizing the battery does not expand the driving range linearly. Note:
35MPa hydrogen tank refers to 5,000psi. (Source: International Journal of
Hydrogen Energy, 34, 6005-6020, 2009)

Doubling battery size does not extend the driving range linearly and the
vehicle becomes inefficient with increasing weight. Li-ion performs better
than lead acid in energy density, but no battery meets hydrogen with a fuel
cell, or fossil fuel feeding the traditional internal combustion engine (not
shown). Extending the driving range with a larger tank is almost negligible
compared to oversizing a battery. There is a threshold as to battery size
and weight in a vehicle; going beyond a critical point has a negative
return. The vehicle becomes environmentally unsustainable.

Batteries have low calorific value compared to fossil fuel and it makes
little sense to power a freight train, ocean-going ship or large airplane
with batteries. A study reveals that replacing kerosene with batteries could
keep an aircraft airborne for less than 10 minutes. Cost is another issue
and batteries take long to charge. A fill-up that is quickly and
conveniently as topping a tank with liquid or gaseous fuel is impossible
with an electrochemical device.

Charging also needs high power. An ultra-fast EV charge draws the equivalent
electrical power of five households. Charging a fleet of EVs could dim a
city.

Conversely, fossil fuel cannot match the qualities of a battery that is
clean and quiet, and that offers an instant start-up with the flick of a
switch. Although fossil fuel is cheap and readily available, frivolous
burning of this resource must stop to save our planet. Finding alternatives
that are environmentally friendly, economical and durable is a challenge;
the battery fills this requirement only in part.

Advancements made in battery technology in the last 20 years are
insufficient to replace fossil fuel. Pushing the boundaries of the battery
reminds us of its many limitations, which include low energy density, long
charging times, high cost and a short life before the packs quits, often
without warning. Table 1 illustrates the energy densities of common fuels,
including the battery.
 
Fuel Energy by mass (Wh/kg)
Hydrogen (350 bar) 39,300
Gasoline, diesel, natural gas (250 bar) 12,000–13,000
Body fat 10,500
Black coal (solid), Methanol 6,000–7,000
Wood (average) 2,300
Lithium-ion battery 100–250
Lead acid battery 40
Compressed air 34
Supercapacitor 5

Table 1: Energy densities of fossil fuel and batteries
Fossil fuel carries many times the energy per mass compared to batteries,
but electrical power can be utilized more efficiently than burning fossil
fuel. (Compiled from various sources. Values are approximate.)

How to Prolong Battery Life

Driving range is a key consideration when buying an EV. Cost also plays a
role but seldom is battery life mentioned. This may not be the concern for a
tire-kicker, nor does the salesman want to alarm the buyer of possible
service issues later on. What sells is the joy of electric propulsion that
is clean, quiet and exhilarating. Taxpayer subsidies also help.

Batteries have a defined life span and this is apparent with the decreasing
runtime in our mobile phones. EV advocates may argue that a smartphone
battery cannot be compared to an EV battery, that the products are totally
different. That is true, but ironically both use lithium-ion systems. This
article looks at the battery in an EV and mobile phone in terms of runtime
and longevity.

The battery in the mobile phone is consumer grade, optimized for maximum
runtime at low cost. The EV battery, on the other hand, is made to industry
standards with longevity in mind. The dissimilarities do not stop there and
a key difference is how the energy is dispensed.

A mobile phone gets charged at the end of a day and the stored energy can be
fully utilized until the battery goes empty. In other words, the user has
full access to the stored energy. When the battery is new, the phone
provides good runtimes but this decreases with use. In this full cycle mode,
Li-ion delivers about 500 cycles. The user adjusts to the decreasing runtime
and, being a consumer product, the end of battery life often corresponds
with a broken screen or the introduction of a new model. Built-in
obsolescence serves well for device manufacturers and retailers.

The EV battery also ages and the capacity fades, but the EV manufacturer
must guarantee the battery for eight years. This is done by oversizing the
battery. When the battery is new, only about half of the available energy is
utilized. This is done by charging the pack to only 80% instead of a full
charge, and discharging to 30% when the available driving range is spent. As
the battery fades, more of the battery storage is demanded. The driving
range stays constant but unknown to the driver, the battery is gradually
charged to a higher level and discharged deeper to compensate for the fade.

Once the battery capacity has dropped to 80%, the oversize protection is
consumed and the battery maintenance system (BMS) applies a full charge and
discharge. This exposes the EV battery to a similar stress level of a mobile
phone and the driver begins noticing reduced driving range. Battery
replacement may become necessary but the cost will be steep, and much higher
than a combustion engine.

The EV begins to impersonate a mobile phone in terms of obsolescence when
the battery fades. This may be the time when the buyer is flooded with
faster and flashier models; something the smartphone user is all too
familiar with, but price will be the shocker. It’s still too early to tell
how long an EV battery will last. Some say the battery will outlive the car
and find secondary application in energy storage systems.

Driving habits and temperature also affects aging, a characteristic that
came to light when EV batteries operating in a warm climate faded
prematurely. It was learned that keeping a battery at elevated temperature
and high state-of-charge causes more stress than aggressive driving. In
other words, keeping a fully charged Li-ion at 30°C (86°F) and above hastens
the aging process more than driving at a moderate temperature. Many EV
batteries include liquid cooling to reduce heat-related battery fade.

Harsh loading also reduces battery life. Because of its large size, the EV
battery is only being stressed moderately, even during acceleration. In
comparison, the mobile phone draws continuous high current from a small
battery when transmitting and crunching data. This puts more stress on a
mobile phone battery than driving an EV. A battery is also negatively
impacted by the pulsed load of a mobile phone rather than the DC load of an
EV.1

The EV does not disclose the battery capacity to the driver and only reveals
state-of-charge (SoC) in the form of driving range. This is done in part for
fear of customer complaints should the capacity drop below the mandated
level at the end of the warranty period. Less knowledge is often better. The
same restriction applies to a mobile phone battery, although access codes
for service personnel are often available. A new battery has (should have) a
capacity of 100%; 80% is the typical end of battery life.

Dynamic Stress Tests (DST) on Li-ion

All Li-ion batteries fade with time and use, whether in consumer products or
enduring industrial use. Figure 2 explores the longevity of Li-ion batteries
with different charge and discharge end points.
Figure 2: Capacity loss of Li-ion as a function of charge and discharge
cut-off points
Limiting a full charge and discharge prolongs battery life but lowers
utilization. (Source: ResearchGate – “Modeling of Lithium-Ion Battery
Degradation for Cell Life Assessment” )

The Li-ion batteries in the above table perform well but the largest
capacity loss occurs with the pack that is charged to 100% and discharged to
25% (black stars). Cycling between 85% and 25% (green) provides longer
service life than charging to 100% and discharging to 50% (dark blue).

The lowest capacity loss occurs when charging Li-ion to 75% and discharging
to 65%. This, however, takes oversizing to the extreme and the battery is
underutilized. Such practice is applied in satellites to achieve high cycle
life and less for terrestrial applications as it increases cost, size and
weight beyond a reasonable point of return. The dynamic stress test does not
include a battery that is charged to 100% and discharged to zero, as is the
case with a mobile phone. A full cycle provides the best battery utilization
but reduces longevity.

Batteries tested in a laboratory do not always replicate true life
conditions, and the results tend to be better than experienced in field use.
In a lab environment, batteries are cycled over a period of a few months,
often at controlled temperature and with an ideal charge and discharge
regime. Random usage in real life adds the exposure to heat, vibration and
harsh charging practices.

Summary

Batteries do not have a fixed life span, nor do they die suddenly but fade
gradually. Environmental conditions, and not cycling alone, govern
longevity. The user has some control to prolong battery life by avoiding
ultra-fast charges, operating at moderate temperature and avoiding full
charges. Avoiding harsh loads and full discharges also helps. Heat is the
enemy of most batteries and the worst condition is keeping a fully charged
Li-ion battery at elevated temperatures. Even with the best of care, a
battery only lives for a season and the pack will eventually face retirement
when power fades.

Endnote

1. See our article, “BU-501: Basics about Discharging” [
http://batteryuniversity.com/learn/article/discharge_methods
] at Battery University.

Isidor Buchmann is the founder and CEO of Cadex Electronics Inc. For three
decades, Buchmann has studied the behavior of rechargeable batteries in
practical, everyday applications, has written award-winning articles
including the best-selling book “Batteries in a Portable World,” now in its
fourth edition. Cadex specializes in the design and manufacturing of battery
chargers, analyzers and monitoring devices. For more information on
batteries, visit www.batteryuniversity.com; product information is on
www.cadex.com.
[comments can be submitted at bottom of page]
[© incompliancemag.com]




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{brucedp.neocities.org}

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Re: EVLN: EV packs optimized 4longevity, Phone Batteries 4co$t

Electric Vehicle Discussion List mailing list
It's puzzling that the author of this article, Isidor Buchman, allegedly
sets out to write about the differences between mobile phone batteries and
EV batteries, but spends over 40% of his piece dismissing and denigrating
EVs.  

Worse, he rehashes the same old misinformation and ignorance that's been
aimed at EVs for 5 decades.  

Look at this junk.  This is the language of a PR hack, not a scientist.  
Some of it's outright wrong; other parts are just meaningless prattle.  (He
doesn't write, "the vehicle becomes less efficient," but rather "the vehicle
becomes inefficient."  Eh?  Furthermore, no evidence for any declaration is
presented.)

> This [increased range] requires larger batteries that grow
> exponentially with the distance driven.

> ... and the vehicle becomes inefficient with increasing weight.

> There is a threshold as to battery size and weight in a vehicle; going
> beyond a critical point has a negative return. The vehicle becomes
> environmentally unsustainable.

> Batteries have low calorific value compared to fossil fuel, and it
> makes little sense to power a freight train, ocean-going ship or large
> airplane with batteries.

> A study reveals that replacing kerosene with batteries could keep an
> aircraft airborne for less than 10 minutes.

> Cost is another issue and batteries take long to charge.

> A fill-up that is quickly and conveniently as topping a tank with
> liquid or gaseous fuel is impossible with an electrochemical device.

> Charging a fleet of EVs could dim a city.

His tired, old, misinformed anti-EV screed just keeps on going. It kind of
makes you wonder where this "battery expert" gets his funding, doesn't it?

David Roden - Akron, Ohio, USA
EVDL Administrator

= = = = = = = = = = = = = = = = = = = = = = = = = = = = =
EVDL Information: http://www.evdl.org/help/
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Re: EVLN: EV packs optimized 4longevity, Phone Batteries 4co$t

Electric Vehicle Discussion List mailing list
Yeah, I too, found it to be pretty disrespecting of facts.

- no mention of efficiency of gas engines (20%) compared to EVs (85% or
so).
- no mention of the extraction costs for fossil fuels, environmental or
fiscal.
- "exponential" inefficiency as battery weight increases; true, but
wildly exaggerated
- manufacturers start with a limit to 80% usage and relax the limit as
the battery gets older. Really?

There were more, which you listed, and probably others I don't remember.
I wonder how many people read this and lap it up without further
thought.

Peri

------ Original Message ------
From: "EVDL Administrator via EV" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Cc: "EVDL Administrator" <[hidden email]>
Sent: 05-Apr-18 3:17:26 PM
Subject: Re: [EVDL] EVLN: EV packs optimized 4longevity, Phone Batteries
4co$t

>It's puzzling that the author of this article, Isidor Buchman,
>allegedly
>sets out to write about the differences between mobile phone batteries
>and
>EV batteries, but spends over 40% of his piece dismissing and
>denigrating
>EVs.
>
>Worse, he rehashes the same old misinformation and ignorance that's
>been
>aimed at EVs for 5 decades.
>
>Look at this junk.  This is the language of a PR hack, not a scientist.
>Some of it's outright wrong; other parts are just meaningless prattle.  
>(He
>doesn't write, "the vehicle becomes less efficient," but rather "the
>vehicle
>becomes inefficient."  Eh?  Furthermore, no evidence for any
>declaration is
>presented.)
>
>>This [increased range] requires larger batteries that grow
>>exponentially with the distance driven.
>
>>... and the vehicle becomes inefficient with increasing weight.
>
>>There is a threshold as to battery size and weight in a vehicle; going
>>beyond a critical point has a negative return. The vehicle becomes
>>environmentally unsustainable.
>
>>Batteries have low calorific value compared to fossil fuel, and it
>>makes little sense to power a freight train, ocean-going ship or large
>>airplane with batteries.
>
>>A study reveals that replacing kerosene with batteries could keep an
>>aircraft airborne for less than 10 minutes.
>
>>Cost is another issue and batteries take long to charge.
>
>>A fill-up that is quickly and conveniently as topping a tank with
>>liquid or gaseous fuel is impossible with an electrochemical device.
>
>>Charging a fleet of EVs could dim a city.
>
>His tired, old, misinformed anti-EV screed just keeps on going. It kind
>of
>makes you wonder where this "battery expert" gets his funding, doesn't
>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)
>

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Re: EVLN: EV packs optimized 4longevity, Phone Batteries 4co$t

Electric Vehicle Discussion List mailing list
In reply to this post by Electric Vehicle Discussion List mailing list
As for electric airplane flight endurance... we have already seen small conventional type aircraft with 1 hour endurance, and experimental type aircraft (100% solar+battery) with multiple day endurance with transpacific and transatlantic flights.



On April 5, 2018 5:17:26 PM CDT, EVDL Administrator via EV <[hidden email]> wrote:

>It's puzzling that the author of this article, Isidor Buchman,
>allegedly
>sets out to write about the differences between mobile phone batteries
>and
>EV batteries, but spends over 40% of his piece dismissing and
>denigrating
>EVs.  
>
>Worse, he rehashes the same old misinformation and ignorance that's
>been
>aimed at EVs for 5 decades.  
>
>Look at this junk.  This is the language of a PR hack, not a scientist.
>
>Some of it's outright wrong; other parts are just meaningless prattle.
>(He
>doesn't write, "the vehicle becomes less efficient," but rather "the
>vehicle
>becomes inefficient."  Eh?  Furthermore, no evidence for any
>declaration is
>presented.)
>
>> This [increased range] requires larger batteries that grow
>> exponentially with the distance driven.
>
>> ... and the vehicle becomes inefficient with increasing weight.
>
>> There is a threshold as to battery size and weight in a vehicle;
>going
>> beyond a critical point has a negative return. The vehicle becomes
>> environmentally unsustainable.
>
>> Batteries have low calorific value compared to fossil fuel, and it
>> makes little sense to power a freight train, ocean-going ship or
>large
>> airplane with batteries.
>
>> A study reveals that replacing kerosene with batteries could keep an
>> aircraft airborne for less than 10 minutes.
>
>> Cost is another issue and batteries take long to charge.
>
>> A fill-up that is quickly and conveniently as topping a tank with
>> liquid or gaseous fuel is impossible with an electrochemical device.
>
>> Charging a fleet of EVs could dim a city.
>
>His tired, old, misinformed anti-EV screed just keeps on going. It kind
>of
>makes you wonder where this "battery expert" gets his funding, doesn't
>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)
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Re: EVLN: EV packs optimized 4longevity, Phone Batteries 4co$t

Electric Vehicle Discussion List mailing list
In reply to this post by Electric Vehicle Discussion List mailing list
EVDL Administrator via EV wrote:

> It's puzzling that the author of this article, Isidor Buchman, allegedly
> sets out to write about the differences between mobile phone batteries and
> EV batteries, but spends over 40% of his piece dismissing and denigrating
> EVs.
>
> Worse, he rehashes the same old misinformation and ignorance that's been
> aimed at EVs for 5 decades.
>
> Look at this junk.  This is the language of a PR hack, not a scientist.
> Some of it's outright wrong; other parts are just meaningless prattle.

That's how it looked to me as well. Besides the gaffes you pointed out, his use
of charts for H2 are out of place. Also, I've never seen anyone compare
batteries by volume as a figure of merit. Volume is almost never a problem; it's
always weight that counts (KW per KG, and KWH/KG).
--
I look for what needs to be done. After all, that's how the universe
designs itself. -- R. Buckminster Fuller
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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simple bms for leaf cells

Electric Vehicle Discussion List mailing list
 I'm looking for a bms leafs cells from about  50 - 70 volts .
looking for something way cheaper than lihton or orian . maybe just a
simple board with simple fucntions like beep as an alarm , for hvc or lvc,
don't mind doing a little baby siting or mamnaul interevontion .

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Re: simple bms for leaf cells

Electric Vehicle Discussion List mailing list
ken via EV wrote:
>   I'm looking for a bms leafs cells from about  50 - 70 volts .
> looking for something way cheaper than lihton or orian . maybe just a
> simple board with simple fucntions like beep as an alarm , for hvc or lvc,
> don't mind doing a little baby siting or mamnaul interevontion .

Hi Ken,

How "simple" do you have in mind? Do you want a battery MONITORING system
(simply tells you their voltages), or a battery MANAGEMENT system (that actually
does something to correct imbalances)?

The simplest MONITORING system would probably be an optocoupler and LED in
series across each cell. Choose the LED so the voltage drop of the optocoupler
LED plus the indicator LED is your desired over-voltage. For example, if you
want it to be 4v, and the opto LED has a 1.1v drop, then pick a blue or white
LED with a 2.9v drop.

Wire the transistor output side of all the optocouplers in parallel, and connect
them to you "overvoltage" indicator or alarm. When any cell goes over-voltage,
it will activate. Then you have to look at the indicator for each cell to see
which one it was.

For low voltage, it's pretty much the same system, except the optocoupler
outputs are all in series. The dropping LED would be a lower voltage (yellow or
green), plus a series resistor to limit the maximum current. When a cell is
above the threshold, the green LED lights and the opto is on. If any cell drops
below the threshold, its optocoupler turns off, which breaks the series loop,
and activates your low-battery indicator or alarm. Again, you have to look at
the LEDs on each cell to know which one it was.

If you want a battery MANAGEMENT system, that will be more complex. The cheap
ones basically stick a resistive load across the cell when it goes over-voltage.
But this assumes that your charger is "smart" enough to go to a current lower
than the bypass current. And, that the BMS can shut down the charger or
controller to prevent over-and under-voltage events.
--
I look for what needs to be done. After all, that's how the universe
designs itself. -- R. Buckminster Fuller
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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Re: EVLN: EV packs optimized 4longevity, Phone Batteries 4co$t

Electric Vehicle Discussion List mailing list
In reply to this post by Electric Vehicle Discussion List mailing list
I didn't read the article, and don't want to defend an anti-EV hack, but
on the question of volume, I can assure you that it can be an issue in
the real world. As I always say, it's a question of the application and
duty cycle.

One example I can think of is the experience of FedEx delivery truck.
They have a number of battery electric delivery vehicles, found that
range just couldn't cut it in at least some places. The obvious solution
is add more batteries, right? No, more batteries would have taken up
valuable cargo space. They could/wouldn't do it. So now they are demoing
fuel cells as range extenders to the battery electrics. It's going very
well, from what I hear. I believe that UPS is doing the same.

---
- Mark

On 2018-04-08 03:37, Lee Hart via EV wrote:

> EVDL Administrator via EV wrote:
>> It's puzzling that the author of this article, Isidor Buchman,
>> allegedly
>> sets out to write about the differences between mobile phone batteries
>> and
>> EV batteries, but spends over 40% of his piece dismissing and
>> denigrating
>> EVs.
>>
>> Worse, he rehashes the same old misinformation and ignorance that's
>> been
>> aimed at EVs for 5 decades.
>>
>> Look at this junk.  This is the language of a PR hack, not a
>> scientist.
>> Some of it's outright wrong; other parts are just meaningless prattle.
>
> That's how it looked to me as well. Besides the gaffes you pointed
> out, his use of charts for H2 are out of place. Also, I've never seen
> anyone compare batteries by volume as a figure of merit. Volume is
> almost never a problem; it's always weight that counts (KW per KG, and
> KWH/KG).
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Re: simple bms for leaf cells

Electric Vehicle Discussion List mailing list
In reply to this post by Electric Vehicle Discussion List mailing list
On Sun Apr 08 06:05:53 PDT 2018 [hidden email] said:
>If you want a battery MANAGEMENT system, that will be more complex. The cheap
>ones basically stick a resistive load across the cell when it goes over-voltage.
>But this assumes that your charger is "smart" enough to go to a current lower
>than the bypass current. And, that the BMS can shut down the charger or
>controller to prevent over-and under-voltage events.

The one I've built for my leaf cells will tell you if any cell has gone under/over. (a single LED for the whole pack)
It does up to 200ma or so of bypass regulation, which seems to be enough to keep my cells balanced.
If you go overvoltage during charge, it turns on a relay - which I've wired to the Reg Shutdown line on my PFC charger.


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Re: EVLN: EV packs optimized 4longevity, Phone Batteries 4co$t

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That’s not how FedEx tells the story. Apparently they experiment with all sorts of new technologies.

https://www.greencarreports.com/news/1094920_fedex-tests-wrightspeed-electric-trucks-with-diesel-turbine-range-extender

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> On Apr 7, 2018, at 10:02 PM, Mark Abramowitz via EV <[hidden email]> wrote:
>
> I didn't read the article, and don't want to defend an anti-EV hack, but on the question of volume, I can assure you that it can be an issue in the real world. As I always say, it's a question of the application and duty cycle.
>
> One example I can think of is the experience of FedEx delivery truck. They have a number of battery electric delivery vehicles, found that range just couldn't cut it in at least some places. The obvious solution is add more batteries, right? No, more batteries would have taken up valuable cargo space. They could/wouldn't do it. So now they are demoing fuel cells as range extenders to the battery electrics. It's going very well, from what I hear. I believe that UPS is doing the same.
>
> ---
> - Mark
>
>> On 2018-04-08 03:37, Lee Hart via EV wrote:
>> EVDL Administrator via EV wrote:
>>> It's puzzling that the author of this article, Isidor Buchman, allegedly
>>> sets out to write about the differences between mobile phone batteries and
>>> EV batteries, but spends over 40% of his piece dismissing and denigrating
>>> EVs.
>>> Worse, he rehashes the same old misinformation and ignorance that's been
>>> aimed at EVs for 5 decades.
>>> Look at this junk.  This is the language of a PR hack, not a scientist.
>>> Some of it's outright wrong; other parts are just meaningless prattle.
>> That's how it looked to me as well. Besides the gaffes you pointed
>> out, his use of charts for H2 are out of place. Also, I've never seen
>> anyone compare batteries by volume as a figure of merit. Volume is
>> almost never a problem; it's always weight that counts (KW per KG, and
>> KWH/KG).
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Re: simple bms for leaf cells

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a bms or pcm  like used for electric bikes. a single board , with all the
long cell wires and a HVC charger cut off and LVC buzzer .
hybridauto had something like it on there goft cart pack.

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