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From: Ross Herbert on 31 Jul 2010 23:57
On Fri, 30 Jul 2010 19:03:24 -0400, "Martin Riddle" <martin_rid(a)verizon.net>
wrote:

:
:
:"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote
:in message news:0ok6561m4ftedj3mv5368vmm8gdc432fln(a)4ax.com...
:> On Fri, 30 Jul 2010 14:14:05 -0700, Jim Thompson
:> <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote:
:>
:>>GM's Electric Lemon...
:>>
:>>http://www.nytimes.com/2010/07/30/opinion/30neidermeyer.html?partner=rss&emc=rss
:>>
:>> ...Jim Thompson
:>
:> Anyone have any idea how many kWh of charge is required for the
:> "electric range" of 40 miles?
:>
:> ...Jim Thompson
:
:
:From the chevy web site, it looks like ~ 13kwh.
:That's from their $1.50 a day and 12c a kwh.
:
:<http://www.chevrolet.com/pages/open/default/future/volt.do>
:
:But, I hear the Prius's batteries tend to become unbalance after a few
:years, and they need to be painstakenly charged and balanced.
:
:I'm not convinced yet.

Me neither....

All of the DIY electric vehicles I have inspected employ a cell equalisation
circuit on every lithium-ion cell in the string. I guess that would be just too
expensive for GM.

:
:BTW, the Volts battery capacity is rumored to be between 25% and 75% of
:the actual cell capacity. Otherwise the batteries will not last.
:Probably due to heating during discharge (25%) and heating during charge
:over 75%.
:Wonder if they are still having 'Thermal' Events' ;)
:
:Cheers
:
:
From: Grant on 1 Aug 2010 01:32
On Sun, 01 Aug 2010 11:57:41 +0800, Ross Herbert <rherber1(a)bigpond.net.au> wrote:

>On Fri, 30 Jul 2010 19:03:24 -0400, "Martin Riddle" <martin_rid(a)verizon.net>
>wrote:
>
>:
>:
>:"Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote
>:in message news:0ok6561m4ftedj3mv5368vmm8gdc432fln(a)4ax.com...
>:> On Fri, 30 Jul 2010 14:14:05 -0700, Jim Thompson
>:> <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote:
>:>
>:>>GM's Electric Lemon...
>:>>
>:>>http://www.nytimes.com/2010/07/30/opinion/30neidermeyer.html?partner=rss&emc=rss
>:>>
>:>> ...Jim Thompson
>:>
>:> Anyone have any idea how many kWh of charge is required for the
>:> "electric range" of 40 miles?
>:>
>:> ...Jim Thompson
>:
>:
>:From the chevy web site, it looks like ~ 13kwh.
>:That's from their $1.50 a day and 12c a kwh.
>:
>:<http://www.chevrolet.com/pages/open/default/future/volt.do>
>:
>:But, I hear the Prius's batteries tend to become unbalance after a few
>:years, and they need to be painstakenly charged and balanced.
>:
>:I'm not convinced yet.
>
>Me neither....
>
>All of the DIY electric vehicles I have inspected employ a cell equalisation
>circuit on every lithium-ion cell in the string. I guess that would be just too
>expensive for GM.

Got to be done if you want best life out of the battery pack, they
just need to cover warranty period? People buy on price, don't look
at the cut corners manufacturers make to meet the low price demand.

Like the older new cars that one had to remove original plugs and
fit grease nipples in order to perform normal maintenance? You
wouldn't guess the proper part cost much more?

Grant.
>
>:
>:BTW, the Volts battery capacity is rumored to be between 25% and 75% of
>:the actual cell capacity. Otherwise the batteries will not last.
>:Probably due to heating during discharge (25%) and heating during charge
>:over 75%.
>:Wonder if they are still having 'Thermal' Events' ;)
>:
>:Cheers
>:
>:
From: Nunya on 1 Aug 2010 01:48
On Jul 31, 8:57 pm, Ross Herbert <rherb...(a)bigpond.net.au> wrote:

> All of the DIY electric vehicles I have inspected employ a cell equalisation
> circuit on every lithium-ion cell in the string. I guess that would be just too
> expensive for GM.

ANY modern battery pack that does not charge the battery on a per
cell, fully managed basis, is NOT a 'modern' battery pack.

It is NOT expensive at all. Battery watchdog chips and charge
management systems have been around for a long time.
From: amdx on 1 Aug 2010 08:14


--
MikeK
"Don Klipstein" <don(a)manx.misty.com> wrote in message
news:slrni58qrf.8ev.don(a)manx.misty.com...
> In article <qll8569vm8foi514boug1nc2qfasb7gnkl(a)4ax.com>, Jim Thompson
> wrote
> (and I edit for space somewhat):
>>On 31 Jul '10 11:01:04 -0400, John Ferrell<jferrell13(a)triad.rr.com> wrote:
>>
>>>I smell a business opportunity for a younger Techie.
>>>
>>>In a few years there will be a supply of these things around that will
>>>not have a market value that exceeds the cost of a new set of
>>>batteries. A replacement power system that costs less than a battery
>>>set may do well.
>>>
>>>Watch out for new laws that may restrict such things. A niche may
>>>exist under all circumstances. Any one for Steam Power? After all the
>>>Stanley Steamer held speed records for a long time!
>>
>>I suspect it costs more per mile to operate electrically than via
>>gasoline. But I can't find anything on the Volt website other than
>>obfuscated "specifications".
>
> I would go with some figures for cost of energy and efficiency of
> converting energy from one form to another.
>
> Gasoline appears to me to cost lately $2.65 per gallon.
>
> I plug into Google gasoline btu gallon and I see figures mentioned in
> the hits to average-to-my-eyes around 120,000 BTU/gallon, and 115,000
> BTU/gallon gives me the impression as reasonable for the modern stuff
> diluted by ethanol and sometimes MTBE.
>
> A BTU is 1055.9 joules
> (http://msis.jsc.nasa.gov/volume2/appx_e_units.htm)
>
> At this rate, gasoline has 121.43 megajoules per gallon, or 45.8
> megajoules per dollar.
>
> I do have the impression (no web work this minute to support it) that
> car gasoline engines achieve around 25% efficiency of converting chemical
> energy to mechanical energy into the car's transmission, and only at a
> rate that high when "the going is better". Car engines have to do a lot
> of work at RPM and mechanical loading far from their optimum, and they
> often have to burn fuel when they re not moving the car at all. As a
> result, I would like to think of 20% as an "average ballpark figure" for
> car gasoline engine efficiency of converting chemical energy to mechanical
> energy.
>
> "At this rate", gasoline achieves 9.16 megajoules per dollar.
>
> =============
>
> Now, for the electric car alternative:
>
> USA national-average residential electricity cost is nowadays probably
> about 12 cents per KWH. A KWH is 3.6 megajoules. Divide that by .12,
> and the result is 30 megajoules per dollar.
>
> However, there are still the losses between one's electric meter and the
> motor shaft of an electric car:
>
> 1: Household wiring downstream of the house's electric meter. I expect
> a house with wiring to support an electric car to have a nice low
> loss there around 1%, for 99% efficiency. However, many houses that
> get electric cars will need wiring installations/upgrades whose cost
> needs to be considered for return_on_investment.
>
> 2: Efficiency of the battery charging circuitry: My impression based on
> my experience with a bewilderment of specific individual figures for
> efficiencies for modern electronic fluorescent lamp ballasts and
> modern line-powered lighting-grade LED drivers is that a reasonable
> figure is 93%.
>
> 3: Efficiency of the battery storing and releasing the charge:
>
> 3a: Hysteresis between charging voltage and discharging voltage of
> the battery: For sake of argument, I would take on a 12V lead-acid
> battery. I seem to think that a lead-acid battery charged at a
> mildly aggressive rate that appears to me necessary will have most
> of its charge pushed in at a voltage of close to 14 volts, and the
> average voltage per unit charge appears to me to be 13.6 volts (or
> slightly more) to push the charge in.
>
> The average discharge voltage of this battery appears to me to be
> 12.1 volts. At discharge current low enough to make IR drop
> negligible and the battery being discharged and having discharged
> at least half a percent of its charge since last recharge, it
> appears to me that this is 12.7-12.75 volts at 90% charged and
> 12-12.1 volts at 10% charged. Average is probably 12.4-12.5, but
> there is IR drop in the battery and wires connected to it, and a
> motor to move a car appears to me to be a heavy load. I like to
> think that 12.1 volts is "charatable in favor of an electric car".
>
> Ratio of 12.1/13.6 is 89%, a figure that I consider to be somewhat
> "charatable to electric cars". So, I now want to back that down to
> 88% for efficiency for the battery storing and releasing energy.
>
> 4: Efficiency of motor control circuitry: Such as likely-needed
> PWM-based switching motor driver circuitry having simulated output
> resistance. I am guesstimating efficiency of 96% on a good day, due
> to lack of AC-DC conversion in electronic fluorescent lamp ballasts and
> "lighting grade LED drivers", and to a lesser extent lack of fully
> converting pulsed output to AC.
>
> 5: Efficiency of the electric motor: That one I have checked out less,
> other than on the nameplates on a few motors in the near-one-HP
> range (~~ ?? 80%). I would like to think that the electric motor in
> an electric car is 85% efficient.
>
> Total efficiency in an electric car:
>
> .99 * .93 * .88 * .96 * .85, totalling 66.1%, probably optimistically,
> for efficiency of converting billed electrical energy to mechanical energy
> from the electric car's motor.
>
> This appears to me to be 19.8 megajoules per dollar for cost of moving
> an electric car, in comparison to 9.2 megajoules per dollar for cost of
> moving a gasoline-powered one. "So far at this rate", the electric car
> costs about half as much to drive as a gasoline-powered one does.
>
> However, an electric car has further disadvantages:
>
> 1. Initial cost is higher, and initial cost of getting an electric car
> also includes whatever cost of home wiring upgrade needed for
> charging it.
>
> 2. A practical electric car nearly-enough-inherently requires a large
> rechargeable battery, likely to need to be replaced more often than
> "similarly-big-ticket" items in gasoline-powered cars need.
>
> 3. The amount of energy stored in a fully charged battery in an electric
> car will not move it as far as can be achieved by the gasoline in a
> typical gasoline-powered car.
>
> 4. Ratio of peak motor horsepower to loaded vehicle mass so far tends to
> be less with electric cars than with gasoline-powered ones. That wil
> impair an electric car's acceleration, especially acceleration after
> achieving a speed around 30-35 or whatever MPH. That slightly
> impacts ability to handle some somewhat-common emergency driving
> situations, slightly impacts ability to accomplish merging operations
> and lane changes on higher speed roads, and to many people greatly
> impacts enjoyment of driving the vehicle in question.
>
> Even if an electric car achieves as much acceleration at 60 MPH or
> whatever as a fully-loaded 18-wheeler achieves, 18-wheelers are big
> and have a higher rate of achievement of getting fellow motorists to
> accomodate their movements than dinkier energy-efficient cars have.
> (Although that becomes some argument in favor of mandating "usual
> cars" to be "dinkified", but then-again that appears to me likely to
> "not sell well" in USA anytime soon.)
> --
> - Don Klipstein (don(a)misty.com)

The cost of not sending billions of oil dollars to people who want to see
us dead,
PRICELESS


Thanks for the logistics of your analysis.
I think the motors are a little bit more efficient than 85%,
especially if Chevy used 3ph ac motors.
I just checked, they do use 3ph motors.
10hr charge on 120V, 4 hr on 240V.
http://gm-volt.com/chevy-volt-faqs/
MikeK



From: amdx on 1 Aug 2010 08:21


--
MikeK
"Spehro Pefhany" <speffSNIP(a)interlogDOTyou.knowwhat> wrote in message
news:co6956d2d8sf2ri1iutq8mli67d414ob32(a)4ax.com...
> On Sat, 31 Jul 2010 22:35:40 +0300, the renowned Paul Keinanen
> <keinanen(a)sci.fi> wrote:
>
>>On Sat, 31 Jul 2010 18:29:03 +0000 (UTC), don(a)manx.misty.com (Don
>>Klipstein) wrote:
>>
>>>
>>> Now, for the electric car alternative:
>>>
>>> USA national-average residential electricity cost is nowadays probably
>>>about 12 cents per KWH. A KWH is 3.6 megajoules. Divide that by .12,
>>>and the result is 30 megajoules per dollar.
>>
>>Electric vehicles can often be charged outside peak hours, which
>>reduces the production cost in power stations.
>>
>>During peak demand, the peak power is typically produced with simple
>>gas turbines burning expensive fuels, such as gas or oil.
>>
>>Extensive use of electric vehicles will reduce the peak/average ratio,
>>the need for peaking gas turbines is reduced and power plants using
>>cheaper fuels can be operated 24 hours each day.
>>
>>The reduction of the production cost is not necessarily reflected into
>>end user prices (taxes, "Enrons" :-(
>
> Electric cars usually have the ability to use regenerative braking to
> recharge their batteries so they should be particularly advantageous
> in city driving. Gas cars need to add much of the overhead of a full
> electric car (just a smaller battery) to get the same advantage.
>
> I disagree with the article- I think GM made a reasonable choice for a
> first offering in the US. Who would buy a car like the Nissan that
> didn't have a backup gas engine? What if you forget or are unable to
> charge it? What if you want to take it on a long drive? And it's silly
> to try to connect the bail-out with the Volt. GM's problems are more
> to do with their current unexciting and (in some cases)
> award-winningly ugly product lineup.
>
> As far as it being cheap to operate- watch out for laws that would
> require separately monitored outlets, perhaps for off-peak charging or
> some kind of bogus safety reason, so that extra road taxes can be
> tacked on to the electrical rates at a later date.
>
>
> Best regards,
> Spehro Pefhany

I like the idea of the small engine driving a generator.
I commented on the DIY electric car forums that they should develop
a small trailer with a motor/generator to hookup when they expect a
longer trip. No need to carry the extra weight if your only going 30 miles.
The idea did not go over with great acceptance.
MikeK



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Prev: OPERATIONS AND SUPPLY MANAGEMENT 13-E JACOBS Test Bank and solution manual is available for purchase at affordable prices. Contact me at alltestbanks11[at]gmail.com to buy it today. All emails will be answered ASAP.
Next: Frigidaire refrigerator temperature control ?