2008 Prius stats revealed: lithium-ion and 94 mpg !!

<div class='quotetop'>QUOTE(kirbinster @ Apr 10 2006, 12:38 PM) [snapback]237601[/snapback]</div>

Thanks kirbinster...I was going to say the same thing. It seems that we would just be trading the burning of one fossil fuel for another unless you could hook into solar cells at home or at a refueling station.

 

Refining gasoline takes electricity as well. So using less gasoline may balance out as no additional electricity consumed.

(Darell, jump in with some references if you have them).

Nate

 

Also, it's much easier to mitigate pollution from relatively large sources than millions of small sources. Furthermore, electricity usually comes from a mix of sources with varying carbon foot prints. If history is any indicator, the amount of carbon in the energy mix has been trending downward.

 

You know what?

If there are EVs or Plugin Hybrids out now, I would have paid to get one. And then pay again to get the solar panel installed on my roof. Since there is no option out yet, paying for solar panel is not going to justify that investment.

I have already minimize my home of electric use already. I use about 350 megawatt/month, or less than $50/month.

 

In MHO the big breakthrough in batteries will be that Li-ION or Li-POLY will not be as memory sensitive(or shorter life) as the current system.
Remember, we only use the 80 -100% range of charge for the HV battery. Just going to a usefull range of 40-100% would triple the EV contribution to gas mileage(in stock configuration).
The weight savings from lighter Li-X batteries would probably be offset by adding more capacity (double?) and keep the current weight.

 

<div class='quotetop'>QUOTE(200Volts @ Apr 10 2006, 01:12 PM) [snapback]237683[/snapback]</div>

Technology is defintely moving forward in battery developement. I think we'll see significant gains here. There is also an agressive push for superior capacitor technology.

Yeah, that's the ticket. I want a flux capacitor that I can dump waste into and generate power.

 

<div class='quotetop'>QUOTE(dipper @ Apr 10 2006, 02:07 PM) [snapback]237678[/snapback]</div>

350 MWh a month? That's some cheap electricity (and a shitload of it too)! Do you mean 350 kWh/month?

 

<div class='quotetop'>QUOTE(nerfer @ Apr 10 2006, 03:31 PM) [snapback]237634[/snapback]</div>

That is a good analysis of cost. The point is that the use of gas or electric under this scenario is about the same, so you have to look at how much more does it cost to buy the newer car that will use electricity better.

As for off-peak power it is a great way to save money. I have time-of-day billing at home plus I have a 10KW solar array on my roof which generates about 12,000 kwh per year. I supply peak power to the grid and draw off peak power to use at night. Just looking as of 4:40pm today I have produced just about 59 kwh of electricity!!!

 

Here's what I found on the UK website for AutoExpress: http://www.autoexpress.co.uk/news/66260/pr...its_113mpg.html

 

<div class='quotetop'>QUOTE(tripp @ Apr 10 2006, 01:27 PM) [snapback]237704[/snapback]</div>

:lol:

Oops... typo. I just came back from lunch, and needed my afternoon nap. Too bad I am at work...

 

I wonder if reliable Lithium conversion kits will be available once the Prius makes the switch. Otherwise, getting new batteries after a few-several years might not be as inexpensive as hoped. I plan to put on 25-35k miles per year, so the batteries are going to go quick for me.

Btw, this topic is also being discussed on http://www.dailykos.com/story/2006/4/10/211839/374 .

 

Can we start building a signup sheet for the newest Prius?

 

A 94 mpg Prius? Yes it can be done but not without a big change. Lighter or bigger batteries wont do it. More electric power wont do it. You need to get more effiency out of the gas engine itself. One way to do this is with an exhaust powered generator. This my friends is not free engergy but it comes close. There is back pressure created but its not as much as the energy extracted. The exhaust actually exits cooler as more energy has been extracted from it.

The exhaust generator would generate more power for electric mode.

94mpg could also come from a HCCI gas engine which also wrings more power out of each gallon of gas.

The control electronics can get about 10% or so better with current advances in semiconductors with almost no increase in cost. They currently get quite hot and newer parts available today generate far less heat.

 

<div class='quotetop'>QUOTE(hampdenwireless @ Apr 10 2006, 11:22 PM) [snapback]237901[/snapback]</div>

Good point, it's about capturing otherwise "wasted" energy. That is the principle behind co-generation at large factories, chemical plants, etc. The otherwise-wasted energy is recovered and put to use.

In co-generation, the power source is preferably a microturbine or a monster reciprocating motor like a Waukesha V-16 – literally big as a house. The exhaust heat is captured and used in other parts of the process.

 

<div class='quotetop'>QUOTE(RonH @ Apr 8 2006, 06:40 PM) [snapback]236926[/snapback]</div>

RonH,
I don't think it's about purely energy density (see figure 1.1 in pdf here: http://www.hardingenergy.com/pdfs/Comparis...pplication.pdf)

I'm seeing that in a mix between volumetric (liters) and gravimetric (weight) energy densities, Li-Ion gets about 1.5x the rating of NiMH. So yeah, you're right about the similarities in numbers.

However, if you look at the content in the article, you may see a good reason that Li-ion is better than NiMH:

So if you have the software to regulate the charge appropriately (which the Prius already has in spades), then you can get a much better charge cycle than in a NiMH, thus letting the system use more of the battery (ie, it could return more like 2x the energy density of the NiMH battery).

In any case, LiIon alone won't do impressive things for their numbers, unless they also modify the gas engine, as others mention.

 

Sorry if what I say has been covered, but I don't have time to look at all the posts ... this is for the discussions about the fuel economy of the plug in

In another prius group (I believe the Yahoo! Prius 2g group), one member discussed his findings that increasing the battery capacity (by adding his own NIMH’s) lead to higher highway fuel economy. The reasons were 1) more regenerative braking and 2) some battery dumping/charging mode that increased in frequency with battery capacity and thus somehow improved highway fuel economy. You wouldn’t be so far off by stating that, at least for long distance driving. Let’s not forget that the two biggest killers (in my experience) of fuel economy are short drives and cold weather (which impacts the ICE efficiency because the Prius ECU utilizes more gasoline to keep up the high combustion ratio – the colder the air the more dense it is, and combined with the high gas/air ratio means that the Atkinson cycle engine takes more of a fuel economy hit with colder temperatures…

A side point - not sure how this correlates with Otto cycle engines – but I do know that the RX400h uses the standard Otto cycle, and that my parents’ RX400h only drops like .5 to 1 mpg to 24.5 (miles/gallons real calculation) when they drive it. Their Acura MDX got 15-18 mpg under the same conditions, just for comparison.

But anyhow with the plug-in technology, the biggest factor for low mileage is wiped out… the warmup factor. If you look at your efficiency diagram the very first warmup is pretty much always the lowest bar – unless the car is warmed up already or your commute is uphill for that drive. Hence, I would venture to say that the fuel economy estimates for a plug-in hybrid vehicle on plug-in power would better approximate real world fuel economy than would the EPA stats for a typical ICE vehicle. The electric drive system is far, far simpler than the ICE itself and affected by far fewer variables (like air density).

All that said, the basic conclusion is that the more miles that are within plug-in range, the higher your fuel economy will be. If your commute was 4 miles one way you could either run on no gasoline or get something like 500 mpg (just for the commute).

 

Tideland,
I thought I read somewhere that the Prius only uses 20% of the available charge so as to maximize the battery life by avoiding "deep" discharges and charging (probably also to avoid heat-hense the reason for the cooling duct to the battery pack).
I'm not refering to what is displayed on any of the SOC displays without an actual voltage measurement. Plus I guess we should define "available" charge. In my experience NiCd/NiMH start at 1.2 to 1.25V and are considered dead at 0.8V
So my 20% drop is from 1.2V to 1.12V per cell, since I consider the reasonable available range as 1.2-0.8=0.4V per cell.