Repair-It

Another ELR review just published today: http://www.greencarreports.com/news/109 ... xury-coupe

I found this comment in that article:

Nothing wrong with the motor. A "hacked" Volt goes 0-60 in a little over 5 secs. so it is the same as putting a governor on your V-8. The Voltec drive system can be set to a wide range of performance.

I guess I should have figured this would become a thing. But maybe given the complicated electronics I wasn't sure. Though I'd be surprised if anyone actually flashed the PCM. But it's GM so maybe?

Here's a battery study for the Volt:

http://www1.eere.energy.gov/vehiclesand ... t_3929.pdf

It'll manage a 14.5C discharge rate at 50% state of charge. It is a 16.6 kWh pack.

I guess this is probably a Li-Ion thing but at around 50% SoC, it has the lowest resistance to pulse charging and discharging, which means you can charge/discharge at the highest rate around 50% SoC. In other words, it becomes harder to charge/discharge the battery if it is very discharged, or very charged (relatively speaking). Although this seems to be contradicted by Figures 4 & 5. Perhaps 50% SoC is just a standard place to measure peak pulse charge/discharge. Figures 4 & 5 indicate that peak pulse discharge is highest at 100% SoC and peak pulse charge is highest at 0% SoC, which is less surprising. But I thought it would have tracked resistance vs SoC... Bob?

Right around 15.5kWh of discharge (6.6% SoC) the voltage vs discharge falls off a cliff. Fortunately in use, the SoC goes nowhere near this.

The gas analogies are interesting and really paint a picture of how immature this is compared to gas as an energy storage medium. Roughly translated, it means the performance of your car would vary as the tank empties. It means if you empty your tank more often (or faster) you'll have to replace it more often (sort of applies to the fuel pump but we're talking a $200 pump in 50k miles if you're REALLY bad). The ICE may be inefficient but it takes very little energy to move gas into the tank or into the engine (as opposed to a motor controller or battery controller which does require substantial cooling). EVs heavily manage the battery, of course, so in the real world, vehicle performance stays pretty flat. But in a gas situation, you have the flexibility to use literally almost 100% of your stored energy (as fast as you want to) with no performance or reliability penalty.

The EPA limits gas dispensing rates to 10 GPM. Assume a typical pump manages 8 GPM. E10 has 32.8 kWh/gal (source: http://en.wikipedia.org/wiki/Gasoline_gallon_equivalent). A 16 gallon fill moves 524.8 kWh worth of energy in 2 minutes, which is equivalent to a charge rate of 15.75 MW (yes, mega) or 30C. People spend $1000 or more for a Level 2 home charger which gives a charge rate of around 7 kW. Feel free to check my math...

I think asking the grid to move similar kinds of power is really not possible and would call for a different paradigm and/or compromises in an all-EV future. Other EV benefits will completely evaporate in the future. Right now, EV's are cool, "new" (in the sense of what's old is new again), heavily tax subsidized (both development AND the purchase), and often get free perks like free charging at work or other locations, because there are practically none on the road. When everything is an EV, those perks go away. I think this is an important point because some of the rationale for buying an EV are actually tied to these perks, when it's actually a pretty transient thing. You can't sell an all-EV future on these perks (which I perceive is kind of happening right now). But it drives early adoption so that's fine

GM has sold 105 ELRs from mid-December through Feb. That's a roughly estimated $7.9M in gross sales revenue. The premium pricing model was a directive from top level management to recoup R&D at a brisk pace, probably hoping that the high price would also add a bit of a halo to the model (market research has always indicated things that are supposed to be premium often sell BETTER at inflated prices).

I believe the Volt only actually uses 60-65% of the total capacity of the battery which should keep it comfortably outside of the dangerous SOC range. The batteries in EVs are usually operating well inside of the maximum limits of the battery. You're probably not likely to see anywhere close to 14C discharge im a Volt with stock programming and you certainly wont notice any difference in performance when the battery is at "full" or "empty" SOC. It is interesting that people are learning how to hack the Volt. There is probably a lot of range and performance to be gained at the expense of the battery.

You forgot to account for the inefficiency of the ICE with your gasoline analogy. Of course, even when you do that, you're still getting a lot more driving range per minute into the car when filling up with gas than you are when you're connected to the fasest charging systems out there. As you said, it's a technology that is still in the very early stages of development.

I suspect, but don't know for sure, that pure EV cars use a lot more of their SoC range. Compared to a Prius, I think the Volt uses MORE of its SoC. But maybe that's wrong.

I didn't mention the inefficiency of the ICE because I was talking strictly about energy transmission. It's kind of crazy that you can transmit 15.75 MW worth of energy flow with practically zero loss. I would say, at a high level, that the transmission of energy from the source to the EV is riddled with inefficiencies (double negative if the plant is burning fossil fuels), but the motor itself is fairly efficient. Gas is the opposite. Pretty good efficiency right up until you turn the chemical enery into motive power.

I think that's why I think I prefer hydrogen fuel cells and make the electricity right onboard. You probably have a different opinion

Bob wrote:http://www.greencarreports.com/news/109 ... ent-at-all

I'm sure most of you have seen this ad by now. The ad certainly didn't make me want to run out and buy an ELR, but it might be appealing to the type of person who would spend $80k on a Cadillac Volt when you can get a perfectly good Tesla S for that kind of coin.

Now Ford has released their parody of the ad: http://youtu.be/jAN61QK0aUI

I finally watched both. All I will say is I read through every single comment on this post: http://cleantechnica.com/2014/03/11/gm- ... ommercial/

Ok, I lied. That's not all I will say. In short, my opinions fall pretty strongly inline with DKB123 on those comments...

The slightly longer version is I continue to be bothered by people who insist the only way you can have a successful life is if you are born with a silver spoon in your mouth. It is a very disconnected view, but critically, supporting that view allows the do-nothings to feel morally comfortable that success is beyond them, so why work hard? Foolish.

I'm also bothered by the fact that "working hard" has become some kind of controversial concept. Working hard to get to the next phase of progress is what has historically driven this country's economic engine.

I don't even know where to begin...

Looks like a good time for a test drive: http://blog.caranddriver.com/cadillac-e ... ly-exists/