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Old 12-22-2017, 07:57 AM
 
Location: The Driftless Area, WI
7,134 posts, read 4,971,954 times
Reputation: 17481

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I agree that there are intangibles that cannot be quantified.

OTOH-- your 130MW produced over 20 yrs is only ~550kW/m-- ~1/2 an average household (not charging an EV) uses. Good for you if you're conserving that much.

Also in the news today from Germany: https://www.welt.de/wirtschaft/artic...packungen.html

100 of Germany's 36,000 buses are electric. When temps fall to ~25*F, their range when using the batteries to provide heat falls from 200km to 125 km. That requires too much re-charging during service hours, so they are equipped with Diesel motors for heating purposes. Not coming under the same air quality regs as motors used to propel vehicles, they are polluting much more than the standard ICE powered buses. With these drawbacks in mind, Germany is conducting a pilot program study to see if wider use of E-buses is feasible. All engineering solutions require trade-offs.
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Old 12-22-2017, 01:59 PM
 
1,860 posts, read 2,198,645 times
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Quote:
Originally Posted by guidoLaMoto View Post
I agree that there are intangibles that cannot be quantified.

OTOH-- your 130MW produced over 20 yrs is only ~550kW/m-- ~1/2 an average household (not charging an EV) uses. Good for you if you're conserving that much.

Also in the news today from Germany: https://www.welt.de/wirtschaft/artic...packungen.html

100 of Germany's 36,000 buses are electric. When temps fall to ~25*F, their range when using the batteries to provide heat falls from 200km to 125 km. That requires too much re-charging during service hours, so they are equipped with Diesel motors for heating purposes. Not coming under the same air quality regs as motors used to propel vehicles, they are polluting much more than the standard ICE powered buses. With these drawbacks in mind, Germany is conducting a pilot program study to see if wider use of E-buses is feasible. All engineering solutions require trade-offs.
That 130MW is "guaranteed" and the actual will be higher if I see less than a 1.2% annual degradation in efficiency. Having the array since April, I'm projecting 640kWh of production per month. Before the EV and living like an energy-miser, we would consume on average 370kWh per month, but we didn't live nearly as comfortably. I bought into the California energy shortage after our local nuclear power plant was decommissioned, but I started reading up on the politics of utility companies and power plant developers causing me to want to reduce my exposure to them.

As for Germany, I've heard about the inefficiency of EVs in cold weather. Luckily for me, we average a cool 68*F here with highs in the mid 90s and overnight lows in the 40s. I'm surprised they would use diesel to heat the batteries because diesel will start to crystalize at temps below 32*F. My TDI and Duramax never seem to need their glow plugs because again, I'm in southern California. But back to the German buses, so you're saying they use an electric motor for propulsion, a diesel motor for heating the batteries, and I assume electric glow plugs to warm the diesel fuel? We'll see how solid state batteries change the game, but the way I see EVs is that it's a part of progress. Current EVs are much better than the old NiMH or NiCad batteries from 10-17 years ago. I'm sure in 5 years we will look back on the current EV technology in the same manner.
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Old 12-22-2017, 06:33 PM
 
Location: The Driftless Area, WI
7,134 posts, read 4,971,954 times
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I guess I didn't explain that very well: the Diesel engines generate heat for the passengers. I'm thinkin' how much heat do they need?-- it's winter and they're presumably dressed for it. Body heat on a crowded bus at rush hour should be good enough for the short commutes. Those Euro-trash sissies gotta toughen up a little

I should also think that propane heaters would be much cleaner and more efficient than Diesels. ICE exhaust is a particularly bad problem in European cities: high pop. density in confined spaces, often in mountain valleys. The acidic air is ruining the centuries old public statuary & artistic building facades. The soot generated is also the main reason the Alpine glaciers are melting faster than their natural rate.

As far as batteries go, technology is advancing: first generation EVs were thoroughly lousy. Now they're mediocre. Big improvement. To get batteries that will make an EV truly competitive with an ICE vehicle for convenience will take a major new breakthru in battery technology. Don't hold your breath waiting.

Evs have a larger niche in warm climates, but in most of the country the cold seasons really lower the battery range.
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Old 12-22-2017, 07:20 PM
 
Location: Forests of Maine
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My plug-in Prius uses electric heat-pumps to heat the passenger cabin.

When temps drop into the -5F to -20F range I do lose range, maybe 20% less range.
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Old 12-23-2017, 05:23 AM
 
Location: The Driftless Area, WI
7,134 posts, read 4,971,954 times
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Quote:
Originally Posted by Submariner View Post
My plug-in Prius uses electric heat-pumps to heat the passenger cabin.

When temps drop into the -5F to -20F range I do lose range, maybe 20% less range.
Let's do a rough calculation to compare electric power to gasoline power. I need to know the range of your vehicle on batteries, how long it takes to re-charge and how many kW-hr to move you thru the full range.

edit: just found this site https://en.wikipedia.org/wiki/Gasoline that states gasoline contains energy of 35.3 kW-hr per gallon.

Let's say we have an ICE vehicle that gets 25mi/gal. An EV of similar weight and driven the same will require charging for 8 3/4 hrs by a 4kW array to drive the same 25 miles-- 3.5x10^1 kW-hr ./. 4kW = 8.75 hr.

A gal of gas ~$2.50/gal 35kW-hr @ $0.15/kW-hr (grid) = $5.25

??? Did I make a mistake in arithmetic, or are the advertisers lying claiming energy cost of an EV is 1/5th that of an ICE, or is the omniscient Wiki wrong?

edit again: just realized the error-- ICE is only ~10% efficient in turning PE of fuel into KE of movement, so 35 kW-hr in the EV probably takes you 10x further down the road than the gal of gas. You may only need ~ 50 min of charging from the PV array to go the 25 miles.

Does that sound about right, Submariner?

Last edited by guidoLaMoto; 12-23-2017 at 06:13 AM..
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Old 12-23-2017, 06:02 AM
 
Location: DC
6,848 posts, read 7,950,998 times
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The German vehicles certainly do not use diesel engines to heat the batteries or passengers. That's a naive and silly explanation. Much more likely is that the bus shifts to diesel power during extremely cold weather.
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Old 12-23-2017, 08:10 AM
 
Location: Forests of Maine
37,250 posts, read 60,994,380 times
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Quote:
Originally Posted by guidoLaMoto View Post
Let's do a rough calculation to compare electric power to gasoline power. I need to know the range of your vehicle on batteries, how long it takes to re-charge and how many kW-hr to move you thru the full range.

edit: just found this site https://en.wikipedia.org/wiki/Gasoline that states gasoline contains energy of 35.3 kW-hr per gallon.

Let's say we have an ICE vehicle that gets 25mi/gal. An EV of similar weight and driven the same will require charging for 8 3/4 hrs by a 4kW array to drive the same 25 miles-- 3.5x10^1 kW-hr ./. 4kW = 8.75 hr.

A gal of gas ~$2.50/gal 35kW-hr @ $0.15/kW-hr (grid) = $5.25

??? Did I make a mistake in arithmetic, or are the advertisers lying claiming energy cost of an EV is 1/5th that of an ICE, or is the omniscient Wiki wrong?

edit again: just realized the error-- ICE is only ~10% efficient in turning PE of fuel into KE of movement, so 35 kW-hr in the EV probably takes you 10x further down the road than the gal of gas. You may only need ~ 50 min of charging from the PV array to go the 25 miles.

Does that sound about right, Submariner?
Whatever it takes for you to get a peaceful night of sleep.

Our sedans turn on their gas engines to maintain themselves warm enough to run at their optimum efficiency [regardless of the state of charge in the drive batteries]. The gas engines turn on and off at will, while we are driving. It does not really affect the heat coming from the air ducts.

When the car senses that it needs more power than what the drive battery can provide, it will start it's gas engine. But for the gas engine to be efficient, it needs to be warm. So even if it is at full charge, it's engine may turn on briefly, just to keep itself warm ready to be called into service.
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Old 12-23-2017, 08:34 AM
 
Location: The Driftless Area, WI
7,134 posts, read 4,971,954 times
Reputation: 17481
Quote:
Originally Posted by DCforever View Post
The German vehicles certainly do not use diesel engines to heat the batteries or passengers. That's a naive and silly explanation. Much more likely is that the bus shifts to diesel power during extremely cold weather.
Plausible guess-- but wrong. Go read the article in Die Welt that I referenced.
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Old 12-23-2017, 08:43 AM
 
Location: The Driftless Area, WI
7,134 posts, read 4,971,954 times
Reputation: 17481
Quote:
Originally Posted by Submariner View Post
Whatever it takes for you to get a peaceful night of sleep.

Our sedans turn on their gas engines to maintain themselves warm enough to run at their optimum efficiency [regardless of the state of charge in the drive batteries]. The gas engines turn on and off at will, while we are driving. It does not really affect the heat coming from the air ducts.

When the car senses that it needs more power than what the drive battery can provide, it will start it's gas engine. But for the gas engine to be efficient, it needs to be warm. So even if it is at full charge, it's engine may turn on briefly, just to keep itself warm ready to be called into service.
Nice story, but it doesn't answer my question. I changed pace a little and got off the heating question.

More directly: how long does it take to charge your car battery off your solar installation? How far can you drive on the batteries alone?
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Old 12-23-2017, 11:41 AM
 
Location: Forests of Maine
37,250 posts, read 60,994,380 times
Reputation: 30135
Quote:
Originally Posted by guidoLaMoto View Post
... More directly: how long does it take to charge your car battery off your solar installation? How far can you drive on the batteries alone?
It takes 5 hours to charge up my Prius, with our 120vac outlets. I could wire a 240vac outlet in our carport that would bring the charging time down to just over 2 hours.

In the summer we can drive 25 miles purely on electric. In winter that drops to between 18 - 20 miles.

We just leave it plugged in after driving it, and until the next time that I need to go somewhere. Sometimes I can make two trips a day.
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