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Do you think battery mileage will increase?

drcarric2650

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I like the idea of the solar option, if you do get stuck in the boondocks, all you have to do is wait for sunlight, not saying you will make it home that night, but you will eventually make it to a charger. Now it will be interesting to see if the solar with the flip outs will create enough power to handle the heat and air for the camp.
 

ajdelange

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Oops. Thought he was talking about installing solar to charge at home. But the comments still apply. It has been pointed out many times here and elsewhere that trying to charge the vehicle from solar panels mounted on it is entirely impractical. That 5.37 number from #15 maps to about 1.35 kWh/m^2•da AC power which would be enough to add perhaps 3 miles to the range per square meter of panel. Lets assume they can get 3 m^2 (3ft x 9ft) of panel onto the toneau or wherever. We're talking 9 miles at the summer solstice and, in the winter, about a quarter of that.
 

drcarric2650

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Oops. Thought he was talking about installing solar to charge at home. But the comments still apply. It has been pointed out many times here and elsewhere that trying to charge the vehicle from solar panels mounted on it is entirely impractical. That 5.37 number from #15 maps to about 1.35 kWh/m^2•da AC power which would be enough to add perhaps 3 miles to the range per square meter of panel. Lets assume they can get 3 m^2 (3ft x 9ft) of panel onto the toneau or wherever. We're talking 9 miles at the summer solstice and, in the winter, about a quarter of that.
You are correct, but look at it this way, how much would it charge in a year, two years... every little bit helps.
 

ajdelange

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If the option is offered I'll probably buy it.Sure. I just try to lend A little perspective. We're talking vehicles with batteries from 100 to perhaps more than 200 kWh capacity and solar panels which can supply about 1 kW from a 4 m^2 array.
 

chphilo

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It looks like CT is roughly about 2 m wide and the bed is about 2 m long. Assuming that the solar panel has to be somewhat smaller than this, let's say the panel is about 3 m^2. It looks like we get about 4-4.5 kWh per m^2 per day on average. (I live in PA). That will give about 12-13.5 kWh per day. Some say that the dual motor CT has 120 kWh battery with 300 mile range. So that should give more than Musk's number (15 miles per day). Factoring in inefficiency not being able to tilt the panel south, etc., Musk's claim definitely does not seem unreasonable. I don't plan to run exclusively on solar power, but not having to charge every night would be nice.

main-qimg-1df462be7aac93e21c69fc982bda6105-c.jpeg
 

ajdelange

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So that should give more than Musk's number (15 miles per day).
That should make you suspicious.

Factoring in inefficiency not being able to tilt the panel south, etc., Musk's claim definitely does not seem unreasonable.
If you have followed him at all you will know that his optimism with regard to the predicted performance of his cars is unbounded. We are supposed to be snoozing in the back seats of our cars while they guide us safely through traffic in out morning commutes by now, aren't we? Thus you can be sure his number was derived for a car parked on a ramp (to tilt the array optimally) in some place like Palm Springs such that the impinging sun is 9 kWh/M^2•da. A 3 m^2 panel will thus receive 27 kWh/da. If the CTs can run on 400 Wh/mi (though note that ABRP uses 485) as suggested by 300 miles range with a 120 kWh battery that would imply 67.5 miles per day (55.67 mi ABRP) if all that impinging energy could be converted to energy stored. But it can't. The Shockley limit is 33.7% which would reduce that number to about 20 miles per day and technology today seems to be in the 20 - 25% region moving that number down to 13.5 - 16.9 miles. Now we have to do DC/DC conversion to get to a voltage suitable for charging the battery so you have to knock off another 10% for that which gets the upper number to about 15 mi/da. Note that the NREL numbers are for an array tilted properly. The array on the CT won't be tilted properly. It will be tilted the way it is tilted unless you use ramps or some such arrangement. The solar system at the house here is aligned as the roof requires but is such that the system produces 95.5% of ideal on a clear day near the summer solstice. From solstice to solstice, however, it only produced 78% of what the monthly NREL numbers predict for the average year. Thus you should probably knock another 20% off for orientation, unusually cloudy or hazy days etc. This would have us down to 12 miles per day. And, of course, where insolation is half of 9 that would get us to 6.

To put it all in perspective one of the competitors has an SUV with an option for a solar roof. Their ads claim that this will collect as much as 1000 miles per year. That's 2.7 mi/da which seems a more reasonable expectation.

don't plan to run exclusively on solar power, but not having to charge every night would be nice.
It isn't even going to save you that not to mention that to get it you would have to park the car outside which, perhaps, you do at work as a matter of course anyway. Using 6 as the yearly average we might expect 9 miles a day in the summer but only 3 in the winter. Assuming we are parked outside around noon (at work) 5 days a week we'd pick up 45 miles per week in the summer and 15 in the winter. In summertime that might cover the vampire drain but in winter probably not even that.
 

chphilo

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I appreciate this analysis. I am not expecting miracle. But at this point, we lack the detail to do precise calculation. But it seems to me his numbers are believable. (unlike some incredible claims by (future?) makers of Atilis truck)

The truck's bed length is about 2 m and width also about 2 m (and tonneau cover is slanted). If it is possible to get solar panel beyond the bed cover, it does not seem impossible to get panel even larger than 4 m^2 size. And who knows what solar panel technology will be used for CT and what sort of tweaking that will be done.. I personally am not interested in foldout solar wings (I am not 100 % sure though), Even with all the limitations, solar power still would be useful for my case. Currently, my truck never sits inside a garage and I drive typically less than 5 miles per day. That might change in a few month when I move to a new place, but I will reevaluate the situation then.


That should make you suspicious.

If you have followed him at all you will know that his optimism with regard to the predicted performance of his cars is unbounded. We are supposed to be snoozing in the back seats of our cars while they guide us safely through traffic in out morning commutes by now, aren't we? Thus you can be sure his number was derived for a car parked on a ramp (to tilt the array optimally) in some place like Palm Springs such that the impinging sun is 9 kWh/M^2•da. A 3 m^2 panel will thus receive 27 kWh/da. If the CTs can run on 400 Wh/mi (though note that ABRP uses 485) as suggested by 300 miles range with a 120 kWh battery that would imply 67.5 miles per day (55.67 mi ABRP) if all that impinging energy could be converted to energy stored. But it can't. The Shockley limit is 33.7% which would reduce that number to about 20 miles per day and technology today seems to be in the 20 - 25% region moving that number down to 13.5 - 16.9 miles. Now we have to do DC/DC conversion to get to a voltage suitable for charging the battery so you have to knock off another 10% for that which gets the upper number to about 15 mi/da. Note that the NREL numbers are for an array tilted properly. The array on the CT won't be tilted properly. It will be tilted the way it is tilted unless you use ramps or some such arrangement. The solar system at the house here is aligned as the roof requires but is such that the system produces 95.5% of ideal on a clear day near the summer solstice. From solstice to solstice, however, it only produced 78% of what the monthly NREL numbers predict for the average year. Thus you should probably knock another 20% off for orientation, unusually cloudy or hazy days etc. This would have us down to 12 miles per day. And, of course, where insolation is half of 9 that would get us to 6.

To put it all in perspective one of the competitors has an SUV with an option for a solar roof. Their ads claim that this will collect as much as 1000 miles per year. That's 2.7 mi/da which seems a more reasonable expectation.

It isn't even going to save you that not to mention that to get it you would have to park the car outside which, perhaps, you do at work as a matter of course anyway. Using 6 as the yearly average we might expect 9 miles a day in the summer but only 3 in the winter. Assuming we are parked outside around noon (at work) 5 days a week we'd pick up 45 miles per week in the summer and 15 in the winter. In summertime that might cover the vampire drain but in winter probably not even that.
 

drcarric2650

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That should make you suspicious.

If you have followed him at all you will know that his optimism with regard to the predicted performance of his cars is unbounded. We are supposed to be snoozing in the back seats of our cars while they guide us safely through traffic in out morning commutes by now, aren't we? Thus you can be sure his number was derived for a car parked on a ramp (to tilt the array optimally) in some place like Palm Springs such that the impinging sun is 9 kWh/M^2•da. A 3 m^2 panel will thus receive 27 kWh/da. If the CTs can run on 400 Wh/mi (though note that ABRP uses 485) as suggested by 300 miles range with a 120 kWh battery that would imply 67.5 miles per day (55.67 mi ABRP) if all that impinging energy could be converted to energy stored. But it can't. The Shockley limit is 33.7% which would reduce that number to about 20 miles per day and technology today seems to be in the 20 - 25% region moving that number down to 13.5 - 16.9 miles. Now we have to do DC/DC conversion to get to a voltage suitable for charging the battery so you have to knock off another 10% for that which gets the upper number to about 15 mi/da. Note that the NREL numbers are for an array tilted properly. The array on the CT won't be tilted properly. It will be tilted the way it is tilted unless you use ramps or some such arrangement. The solar system at the house here is aligned as the roof requires but is such that the system produces 95.5% of ideal on a clear day near the summer solstice. From solstice to solstice, however, it only produced 78% of what the monthly NREL numbers predict for the average year. Thus you should probably knock another 20% off for orientation, unusually cloudy or hazy days etc. This would have us down to 12 miles per day. And, of course, where insolation is half of 9 that would get us to 6.

To put it all in perspective one of the competitors has an SUV with an option for a solar roof. Their ads claim that this will collect as much as 1000 miles per year. That's 2.7 mi/da which seems a more reasonable expectation.

It isn't even going to save you that not to mention that to get it you would have to park the car outside which, perhaps, you do at work as a matter of course anyway. Using 6 as the yearly average we might expect 9 miles a day in the summer but only 3 in the winter. Assuming we are parked outside around noon (at work) 5 days a week we'd pick up 45 miles per week in the summer and 15 in the winter. In summertime that might cover the vampire drain but in winter probably not even that.
Again, think of a million trucks getting that much energy per year.
 

Marc

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It looks like CT is roughly about 2 m wide and the bed is about 2 m long. Assuming that the solar panel has to be somewhat smaller than this, let's say the panel is about 3 m^2. It looks like we get about 4-4.5 kWh per m^2 per day on average. (I live in PA). That will give about 12-13.5 kWh per day. Some say that the dual motor CT has 120 kWh battery with 300 mile range. So that should give more than Musk's number (15 miles per day). Factoring in inefficiency not being able to tilt the panel south, etc., Musk's claim definitely does not seem unreasonable. I don't plan to run exclusively on solar power, but not having to charge every night would be nice.

main-qimg-1df462be7aac93e21c69fc982bda6105-c.jpeg
Raising front and lowering rear could get users better angle towards the sun. Might bump up the numbers a few percent.
 

Huntsman

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Raising front and lowering rear could get users better angle towards the sun. Might bump up the numbers a few percent.
That should make you suspicious.

If you have followed him at all you will know that his optimism with regard to the predicted performance of his cars is unbounded. We are supposed to be snoozing in the back seats of our cars while they guide us safely through traffic in out morning commutes by now, aren't we? Thus you can be sure his number was derived for a car parked on a ramp (to tilt the array optimally) in some place like Palm Springs such that the impinging sun is 9 kWh/M^2•da. A 3 m^2 panel will thus receive 27 kWh/da. If the CTs can run on 400 Wh/mi (though note that ABRP uses 485) as suggested by 300 miles range with a 120 kWh battery that would imply 67.5 miles per day (55.67 mi ABRP) if all that impinging energy could be converted to energy stored. But it can't. The Shockley limit is 33.7% which would reduce that number to about 20 miles per day and technology today seems to be in the 20 - 25% region moving that number down to 13.5 - 16.9 miles. Now we have to do DC/DC conversion to get to a voltage suitable for charging the battery so you have to knock off another 10% for that which gets the upper number to about 15 mi/da. Note that the NREL numbers are for an array tilted properly. The array on the CT won't be tilted properly. It will be tilted the way it is tilted unless you use ramps or some such arrangement. The solar system at the house here is aligned as the roof requires but is such that the system produces 95.5% of ideal on a clear day near the summer solstice. From solstice to solstice, however, it only produced 78% of what the monthly NREL numbers predict for the average year. Thus you should probably knock another 20% off for orientation, unusually cloudy or hazy days etc. This would have us down to 12 miles per day. And, of course, where insolation is half of 9 that would get us to 6.

To put it all in perspective one of the competitors has an SUV with an option for a solar roof. Their ads claim that this will collect as much as 1000 miles per year. That's 2.7 mi/da which seems a more reasonable expectation.

It isn't even going to save you that not to mention that to get it you would have to park the car outside which, perhaps, you do at work as a matter of course anyway. Using 6 as the yearly average we might expect 9 miles a day in the summer but only 3 in the winter. Assuming we are parked outside around noon (at work) 5 days a week we'd pick up 45 miles per week in the summer and 15 in the winter. In summertime that might cover the vampire drain but in winter probably not even that.
I’m in the blueprint stage of building next house. Would like to solar recharge the CT. Any resources suggestions for collectors, data for direct DC to DC charge (maybe without batteries)
 

ajdelange

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That can certainly be done. The path of least resistance is to call a solar installer, have them propose a system, install it and carry on normally. The typical proposal is for a system that will provide 2/3 to 3/4 of your electricity demand and the system works by using the utility as a "battery' but it isn't a coulomb battery, it is a $ battery in the sense that if you are not home during the day then your solar generation will be high but yu aren't there to use it so it goes to the utility who pays you for it at the same rate they charge you for electricity you consume. You come home at night after the sun is down and plug in your CT. It charges from the utility, of course, as the sun is down but you don't get charged for it because you are using the credit you earned when you sold electricity around noon. Did you charge the CT from the solar panels or not? Literally, no but as the effect on your cashflow and CO2 emissions are the same as if you did you might want to accept that solution. If you don't, then things get more complicated quickly. In the common setup I described the only way to insure that all the watt hours going to your CT came from your soar panels is to sit in the truck while charging while simultaneously monitoring the net power being taken from the utility. Only when that is a negative number are you if fact charging the vehicle from the solar panels alone.

As you are in the blueprint phase, you can be sure to have lots of roof space facing south with slope of 33 ° (6..5:10). This is the slope that will give you maximum production over a year but will give you a bit less than half the energy between the autumnal equinox and winter solstice as between the what it gives between the summer solstice and autumnal equinox. You can improve on that ratio a little by going to a steeper pitch. To really work the details requires more engineering than most solar installation companies can afford to give you for a price you will like.

DC/DC solutions may exist but not for the homeowner AFAIK. You would need DC/DC converters that will do maximum power point tracking in the boost circuit and come out with about 400V and a communication system compatible with Tesla - in effect a Super Charger simulator. For charging at home you are going to have to live with the 240 V output of micro inverters feeding the 240V AC input of the truck, You would want this anyway because you are going to be investing in the array which won't be charging the car full time and you can recoup the cost of the array by using or selling the electricity it produces when not charging.
 

Cyber_Dav

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your solar generation will be high but you aren't there to use it so it goes to the utility who pays you for it at the same rate they charge you for electricity you consume.
This is great where you can get it. Our utility company does not allow net metering.

edit: technically they allow 5% of customers to use it, a number that was filled years ago. There is no waiting list.
 

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I'm hoping for a dual motor model with optional LR battery pack.

I don't need or want a tri motor CT, but I do want more than a 300 mile range.
+1 here. I ordered the dual motor, and when I got the confirmation, there was a disclosure saying something along the line that options will offered and finalized upon the actual sale. I am hoping for the biggest battery option and camo color, neither one are deal breakers though. Black will be just fine.
 

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