Time for a Tesla?
06-17-2019, 03:25 PM
#61
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Wow, Ontario is very green on energy. Lot of nuclear, and no coal. Very progressive! A good fit for the Tesla paradigm.
06-17-2019, 09:32 PM
#62
Instructor
I have a 2012 Nissan Leaf that I picked up last year for around 5k. It recently had the pack replaced under warranty (original chemistry wasn't great).
For my driving needs, which are mainly local, it's the perfect car. Very torquey with great AC and really very little to maintain. The heat is good but uses a lot of energy - something newer EVs address with a heat pump. The fact that I can charge at work for free just sweetens the deal.
I grew up rowing gears on a Miata tho, and there's an itch I have about hitting perfectly smooth shifts around corners that an EV (or any automatic for that matter) can't scratch.
For my driving needs, which are mainly local, it's the perfect car. Very torquey with great AC and really very little to maintain. The heat is good but uses a lot of energy - something newer EVs address with a heat pump. The fact that I can charge at work for free just sweetens the deal.
I grew up rowing gears on a Miata tho, and there's an itch I have about hitting perfectly smooth shifts around corners that an EV (or any automatic for that matter) can't scratch.
06-18-2019, 04:44 AM
#63
Instructor
Interesting. You start by saying you can charge your car with the solar power you 'create'. (I know what you mean, you capture it, not create it). Then you go on to mention 'plug it in'. A little back of the envelope math is in order. Using Tesla numbers, the 85Kw/h batt is good for around 300 miles. That breaks down to 283.33 W/m or at an ave of 50 mixed city/hwy lets say 14,667W/h per hour. A 30 min drive in a Tesla will use about 7300 watts, yes?
I've done my share of solar work, so I have a pretty good idea of charge rates, and efficiency. A decent solar panel with 350W STC rating puts out about nominal 240W at 80% irradiance(no one gets 80% irradiance unless they are in the middle of a high desert location like me at 8000' central NM). But, we'll give the benefit of the doubt. Call it 250W so four panels, on a 2 axis mount will give 1000W of pure DC power from roughly 9am-3pm every sunny day. But wait, that 6,000W of pure DC power @ 120 volts doesn't get to go into the car, it has to be converted to AC, to go in the plug, and then converted BACK to DC to charge the batts. So, the best case MPPT charge controller, and best case inverter on the planet run about 89% efficiency - each. (0.89X1000)x0.89 = 792W per day of usable AC power going into the receptacle. One plugs their Tesla into this AC source, and viola! we can now charge the car.
Here's where I lose track. I don't know squat about the charging mechanism of a Tesla. But I do know that our 30 min drive has used roughly 7.3Kw of power. We can charge at 220VAC and get a good 3.6 amps going. If the Tesla uses a good efficiency AC/DC converter(I assume) and they are also getting that 89% efficiency, then the battery is getting about 704WDC/h. If all goes right, and everything lines up just perfect, it will only take 10.5 hours to charge the car fully.
Now, I've been conservative on usage, and liberal on charge rates for a reason. Real world actual conditions tell me that Tesla will take more like 20Kw/h to run(lights, AC, radio, etc). Real world charge rates and irradiance I know for a fact never ever reach 80%. More like 60% is the norm(having built 3 systems from scratch). But lets split the diff and call it 70%. That means we now need not 10.5 hours to charge but ~14 hours. That's two full solar days during the equinox, and 3 days at southern solstice, maybe just possibly one day during the summer solstice. For the 30 min drive.
If we up the solar panel count, we can get better, but at what cost? 4 panels @ $200ea, plus MPPT cntl @ $400, plus inverter @ $1400(non-grid tie) just the bits is around $2600. If we add panels we need a bigger charge controller, and bigger inverter.
Two days to charge the car for a 30 minute drive? Face it, you are 'plugged in' to the grid, unless you have acres of solar, and many $$$$$$ tied up in solar collection. Yes, it has a payback, if you grid-tie and you have a roof full of panels(oops, no longer 2 axis motion, now you are down to 35-45% irradiance) you can sell back power to the provider at 25 cents on the dollar. It will be cost effective in about 22-30 YEARS. If you bought it for the tech, performance, and convenience, that was the right choice, because they aren't all that 'green'.
<edited to correct a bit of math>
I've done my share of solar work, so I have a pretty good idea of charge rates, and efficiency. A decent solar panel with 350W STC rating puts out about nominal 240W at 80% irradiance(no one gets 80% irradiance unless they are in the middle of a high desert location like me at 8000' central NM). But, we'll give the benefit of the doubt. Call it 250W so four panels, on a 2 axis mount will give 1000W of pure DC power from roughly 9am-3pm every sunny day. But wait, that 6,000W of pure DC power @ 120 volts doesn't get to go into the car, it has to be converted to AC, to go in the plug, and then converted BACK to DC to charge the batts. So, the best case MPPT charge controller, and best case inverter on the planet run about 89% efficiency - each. (0.89X1000)x0.89 = 792W per day of usable AC power going into the receptacle. One plugs their Tesla into this AC source, and viola! we can now charge the car.
Here's where I lose track. I don't know squat about the charging mechanism of a Tesla. But I do know that our 30 min drive has used roughly 7.3Kw of power. We can charge at 220VAC and get a good 3.6 amps going. If the Tesla uses a good efficiency AC/DC converter(I assume) and they are also getting that 89% efficiency, then the battery is getting about 704WDC/h. If all goes right, and everything lines up just perfect, it will only take 10.5 hours to charge the car fully.
Now, I've been conservative on usage, and liberal on charge rates for a reason. Real world actual conditions tell me that Tesla will take more like 20Kw/h to run(lights, AC, radio, etc). Real world charge rates and irradiance I know for a fact never ever reach 80%. More like 60% is the norm(having built 3 systems from scratch). But lets split the diff and call it 70%. That means we now need not 10.5 hours to charge but ~14 hours. That's two full solar days during the equinox, and 3 days at southern solstice, maybe just possibly one day during the summer solstice. For the 30 min drive.
If we up the solar panel count, we can get better, but at what cost? 4 panels @ $200ea, plus MPPT cntl @ $400, plus inverter @ $1400(non-grid tie) just the bits is around $2600. If we add panels we need a bigger charge controller, and bigger inverter.
Two days to charge the car for a 30 minute drive? Face it, you are 'plugged in' to the grid, unless you have acres of solar, and many $$$$$$ tied up in solar collection. Yes, it has a payback, if you grid-tie and you have a roof full of panels(oops, no longer 2 axis motion, now you are down to 35-45% irradiance) you can sell back power to the provider at 25 cents on the dollar. It will be cost effective in about 22-30 YEARS. If you bought it for the tech, performance, and convenience, that was the right choice, because they aren't all that 'green'.
<edited to correct a bit of math>
06-18-2019, 08:29 AM
#64
I'm glad to read about your experience with your Model 3. I've been looking to replace my DD and the Model 3 has been high on my list. My only hang up is I'm worried Tesla might not be around. Some folks say they've got so much great engineering in the pipeline that the company will bought by another auto maker or even google or apple. Still, I'm having a hard time pulling the trigger.
My comment is because MY 996 absolutely sucked the soul out of me. Was fun to drive...when it wasnt broken, and well, after 2 engine rebuilds, I was done with that car
And yeah, I'm not one of those people. I mainly bought the car for it's no maintenance and the performance. Not having to ever go to a gas station is a bonus. Free supercharging is nice but I've used that once since I got the car and it was more to just try it out. My gas bill went from $300/month to maybe $40 & my electricity bill went up about $40/month. Once i test drove my friends RWD model I was pretty convinced the Porsche was going up for sale. The next week it was gone and I put my order in for the dual motor 3 and havent regretted one moment.
Love it so much that I am now waiting for their pick up truck to come out so I can replace the last ICE family hauler in my driveway.
Was funny...was at the track this weekend and parked beside some of the super cars, and more people gathered around the 3 than the Lamborghini. The kids especially were very interested in the car. Elon is making kids and children dream of owning a Tesla some day....I remember doing this with Porsche when I was 12. How things have changed.
And yeah, I'm not one of those people. I mainly bought the car for it's no maintenance and the performance. Not having to ever go to a gas station is a bonus. Free supercharging is nice but I've used that once since I got the car and it was more to just try it out. My gas bill went from $300/month to maybe $40 & my electricity bill went up about $40/month. Once i test drove my friends RWD model I was pretty convinced the Porsche was going up for sale. The next week it was gone and I put my order in for the dual motor 3 and havent regretted one moment.
Love it so much that I am now waiting for their pick up truck to come out so I can replace the last ICE family hauler in my driveway.
Was funny...was at the track this weekend and parked beside some of the super cars, and more people gathered around the 3 than the Lamborghini. The kids especially were very interested in the car. Elon is making kids and children dream of owning a Tesla some day....I remember doing this with Porsche when I was 12. How things have changed.
06-18-2019, 10:50 AM
#65
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FWIW, purely to illustrate that its entirely practical with todays technology to cover your daily commute with generation at point of demand i.e direct solar-> car charging, my 52mile daily commute averages 15-16kWh, which is almost exactly a 3 hour recharge on 240V AC power from the panels under which my car is parked in the day. Panels cost about 0.60dollars/watt, fully loaded cost of the system including industrial scale inversion+batteries+distribution and charging stations adds a fair bit more, but still under $1 a watt. Construction cost of the parking structure dwarfed the solar infrastructure cost. Clearly you have to build at scale to hit these kind of numbers, but thats not an issue for a typical new construction Class A office construction project. Its a nice model for future development, the gas station paradigm doesn't work well for EV's and thats unlikely to change in the short term, possibly not even the medium term. It does hit a ceiling at some point, a multistory parking structure has diminishing roof space to car space ratio as you add floors, and I think with current and short term future panel technology only a single or 2 story structure could provision an EV charger for every space with a useful power rating.
https://www.gogreensolar.com/collect...-panels?page=1
15Kw charge rate for 3 hours would be a nice 5Kw/hour @ 240V is pumping 20 amps at the plug. Given the efficiencies I know are inherent in the conversion, you're going to need about 5.7Kw/h of panel power at 100% irradiance. More conservatively, 6Kw or more of panel at 80% irradiance. That's 20 panels at 300W per panel. Each of the 300W panels are about 6x3', or 18sq/ft of area. 20 panels @ 18sq/ft each is coverage of 360sq/ft. That is an array 10 feet wide, by 36 feet long, under 80% percent irradiance, to charge ONE car 3 hours.
There's no magic to this. Most EV cars that are plugged in do not use solar as their power source. The one's that do use solar are no where near $1/w in installed cost. Grid tie is even more expensive than off-grid. I would say a parking structure would be grid tie, but it doesn't have to be so, if the charger setup were not fed by the grid(no nights, no battery, no generator). Pure solar to EV charge has never been done to my knowledge, but willing to see an example.
7.5Kw system is around $10,000 out the door. Installation with grid tie is going to add another $5-8k.
https://www.wholesalesolar.com/18915...75-watt-panels
That's 20 panels, enough to do one car in 3 hours, with some power left over for cloudy days. There are use cases where it works. In the southern states, with lots of sun, and long days solar is getting close to being viable but still the grid beats solar for practical reasons. I wonder if I made a parking structure with a roof, would I put up solar and grid-tie to charge EVs? Might be a profit in there down the road.
06-18-2019, 01:56 PM
#66
Race Director
Are you leasing? I'm assuming, since there's no assumption of maintenance for the battery pack.
I think Musk is a sharp guy, and I appreciate the disruption that Tesla has caused - but the reality distortion field enveloping the Tesla owners I know seems to make at least some of them pretty hostile when it comes to fielding questions about reliability, self-driving issues, etc. All machines break, and powerful machines break more thoroughly than less powerful machines...I think there are going to be some really interesting engineering issues cropping up as the first Tesla start accumulating age and miles. I don't think Tesla's going to fold anytime soon, but at some point Musk is going to have a harder time hiding the growing pains from the general public.
There's an OCEAN of cars to choose from out there; it's fantastic that Tesla piques your interests.
You can't deny that Musk/Tesla have a following. Tesla has also made tremendous strides toward eliminating the stigma that has always been associated with most electric cars...and that's cool. A community behind EV's is crucial; I wonder if/how that effort is hindered by Tesla's not-so-friendly stance toward DIY/enthusiasts...
I think Musk is a sharp guy, and I appreciate the disruption that Tesla has caused - but the reality distortion field enveloping the Tesla owners I know seems to make at least some of them pretty hostile when it comes to fielding questions about reliability, self-driving issues, etc. All machines break, and powerful machines break more thoroughly than less powerful machines...I think there are going to be some really interesting engineering issues cropping up as the first Tesla start accumulating age and miles. I don't think Tesla's going to fold anytime soon, but at some point Musk is going to have a harder time hiding the growing pains from the general public.
My comment is because MY 996 absolutely sucked the soul out of me. Was fun to drive...when it wasnt broken, and well, after 2 engine rebuilds, I was done with that car
And yeah, I'm not one of those people. I mainly bought the car for it's no maintenance and the performance. Not having to ever go to a gas station is a bonus. Free supercharging is nice but I've used that once since I got the car and it was more to just try it out. My gas bill went from $300/month to maybe $40 & my electricity bill went up about $40/month. Once i test drove my friends RWD model I was pretty convinced the Porsche was going up for sale. The next week it was gone and I put my order in for the dual motor 3 and havent regretted one moment.
Love it so much that I am now waiting for their pick up truck to come out so I can replace the last ICE family hauler in my driveway.
And yeah, I'm not one of those people. I mainly bought the car for it's no maintenance and the performance. Not having to ever go to a gas station is a bonus. Free supercharging is nice but I've used that once since I got the car and it was more to just try it out. My gas bill went from $300/month to maybe $40 & my electricity bill went up about $40/month. Once i test drove my friends RWD model I was pretty convinced the Porsche was going up for sale. The next week it was gone and I put my order in for the dual motor 3 and havent regretted one moment.
Love it so much that I am now waiting for their pick up truck to come out so I can replace the last ICE family hauler in my driveway.
You can't deny that Musk/Tesla have a following. Tesla has also made tremendous strides toward eliminating the stigma that has always been associated with most electric cars...and that's cool. A community behind EV's is crucial; I wonder if/how that effort is hindered by Tesla's not-so-friendly stance toward DIY/enthusiasts...
Last edited by 5CHN3LL; 06-18-2019 at 07:48 PM.
06-19-2019, 04:00 AM
#67
Instructor
Clearly its horses for courses, this is an ideal system for California, with mostly blue skies at 37 degrees latitude. In Norway, you have all the hydro you could possibly ever consume. The UK or Denmark you have vast off shore wind potential. In France you have a night time Nuclear base load that needs to be consumed. But again, its an elegant model adapted to our local resources, that makes daily driving an EV a compromise free proposition for most folks.
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carlvs (07-20-2019)
06-19-2019, 10:45 AM
#68
Rennlist Member
Originally Posted by AWDGuy
I charge every night to recoup the days loss. Takes about 2.5 to 3 hours to recharge the 100km I used during the daily commute. I'm sleeping in my bed while that happens.
06-19-2019, 05:46 PM
#69
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06-19-2019, 06:09 PM
#70
Three Wheelin'
I don't think so
First of all sure the acceleration is a blast...but what then...no SOUND?
I still miss the sound of the AIR COOLED 911'S.
One of these days I'll get to putting a Gundo or Fister on my 996...No TESLA for me.
I'll live out my life with the smell of oil and gas.
Daniel....OLD guy
First of all sure the acceleration is a blast...but what then...no SOUND?
I still miss the sound of the AIR COOLED 911'S.
One of these days I'll get to putting a Gundo or Fister on my 996...No TESLA for me.
I'll live out my life with the smell of oil and gas.
Daniel....OLD guy
06-19-2019, 11:45 PM
#71
Instructor
I own a 996TT and a Tesla 85D. I absolutely love them both. That said, I cannot comment on a 996, but if I owned one, I would not trade it in. I would keep it. That said, I traded a 07 Cayman 2.4 and purchased the 996 because the Tesla spoiled me.
06-20-2019, 08:25 AM
#72
Rennlist Member
Originally Posted by docmirror
That is an array 10 feet wide, by 36 feet long, under 80% percent irradiance, to charge ONE car 3 hours.
06-20-2019, 12:15 PM
#73
Pro
Owning a 996 is much, much greener and environmentally sensitive than buying a Tesla. Why, because we save the energy and materials input to build a new Tesla. We are reusing, and recycling -- much more environmentally useful. And like stated above, the EV simply shifts the carbon pollution away from the car's exhaust to the power plant exhaust (until we truly have the grid supplied by renewables).
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shurton (06-21-2019)
06-21-2019, 01:26 PM
#74
So those of you that think you're saving the earth with your electric car, think again.
06-21-2019, 02:26 PM
#75
Rennlist Member
We've owned a 2014 Volt for nearly 5 years as our only car before getting an 03 c4s three months ago. The Volt has traveled over 70k miles and we are averaging nearly 97 mpg (slightly over 700 gallons used in 5 years). In 3 months i've put 5k miles on the 996 and used almost 275 gallons.
If i want efficiency i'll drive the EV, if i want to have fun i'll drive the 911. Nothing can match the sound of driving, windows down, through a tunnel at 5k rpm with factory sports exhaust on.
If i want efficiency i'll drive the EV, if i want to have fun i'll drive the 911. Nothing can match the sound of driving, windows down, through a tunnel at 5k rpm with factory sports exhaust on.