Like the illusion of Wall Street, with its vast and powerful investment banks, now shuttered, China too is an illusion perpetuated by the Globalists that gave us the 15,000 mile Caesar salad, poisoned cat food and lead based paint on babies' pacifiers. Like the illusion that money would come from thin air to always push housing prices higher, China has spent a generation pursuing its illusion. Pursuing an unattainable dream to be like the West, while 6000 years of its carefully shepherded top soil blows into the sea.
Joined: Jun 05, 2006 Posts: 252 Location: Over the tracks, left under the overpass, right, third boxcar on the left, ask for Jack
Posted: Thu Aug 28, 2008 2:23 pm Post subject: Re: Power Grid Limits Potential of Renewable Energy
Oh OK Yes, I calculated the overall efficiency at 14% Maybe I'm being overly generous in setting the drive train efficiency at 25%. If you take ICE power to the wheels at as low as 15% the overall energy efficiency reduces to 8.5% nominally. For auto use, we are wasting 91.5% of the oil energy that is pumped from the ground!! It's criminal.
Posted: Thu Aug 28, 2008 4:19 pm Post subject: Re: Power Grid Limits Potential of Renewable Energy
Your charging efficiency number is off as well. Flooded lead comes in around 70%, sealed lead AGM types even higher above 90%
Charging
Lithium even better near 99%
Lithium
These numbers and the other changes yesplease pointed out push your calculations even further in favor of EV's and further points out the irrationality of wakeupman's rant. _________________ The shovel with a wheel - The Wovel.
http://wovel.com/
Joined: Jun 05, 2006 Posts: 252 Location: Over the tracks, left under the overpass, right, third boxcar on the left, ask for Jack
Posted: Thu Aug 28, 2008 6:33 pm Post subject: Re: Power Grid Limits Potential of Renewable Energy
As I understand it, there are two components to charging. The charger itself is between 70 - 75 % efficient and the battery charging performance can be as you have stated.
I would certainly like to see the electrical systems become really efficient. There is no question that they offer the greatest hope, but storage for use on demand represents a major and difficult challenge.
Posted: Thu Aug 28, 2008 7:07 pm Post subject: Re: Power Grid Limits Potential of Renewable Energy
I think that battery charger efficiency can be all over the board, depending on quality of components chosen.
One strategy for charging lead-acid (that I use a fair amount) is to charge only to the gassing or Absorption voltage (i.e. about 14.4 volts for a 12 volt battery) then shut off the charger. This typically works more efficiently as energy isn't used to "bubble" the electrolyte. This returns 80-90% of capacity to the battery, which is enough, particularly in warmer weather when lead-acid works best. Lead-acid batteries need to be completely charged i.e. sit at constant voltage at least once a week minimum (approx.) but this is a bit less efficient.
ICE's are constrained by Carnot. Fossil fuels are so energy/power dense that we've let vehicles get way too big and heavy and haven't spent much attention on innovative design. EV's demand cleverness and I think we'll see a lot of new, great ideas in the next few years.
Posted: Thu Aug 28, 2008 7:15 pm Post subject: Re: Power Grid Limits Potential of Renewable Energy
According to the DOE, after taking into account the charging/discharging efficiency of NiMH batteries, the charger efficiency was ~85%. Supposedly the charging efficiency of the AC-150 is 90%+, which is supported by the manufacturer although it can drop to 50% w/ 110V and the lowest charging current at around ~200W. _________________
Professor Membrane wrote:
Not now son! I'm making...TOAST!
Last edited by yesplease on Thu Aug 28, 2008 8:14 pm; edited 1 time in total
Posted: Thu Aug 28, 2008 7:20 pm Post subject: Re: Power Grid Limits Potential of Renewable Energy
85% and greater seems fairly common for lead acid chargers. I'm sure that could be much better for SLA and lithium chargers since those batteries don't need to bubble for complete charging. _________________ The shovel with a wheel - The Wovel.
http://wovel.com/
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