Aug-14-2019 07:44 AM
Sep-03-2019 06:08 PM
Sep-03-2019 03:57 PM
Aug-16-2019 07:31 PM
wanderingaimlessly wrote:
For the electrical engineers that really want to get into the weeds on this, real question for you.
IF you had a Tesla truck and TT and ran out of power in the desert southwest. And you had a trailer with 400 watts of solar, and a 430 Amp/hr battery pack. Along with a 1500 watt inverter.
How long would it take to generate enough power to get the truck, without the trailer, 20 miles, to a real power source for recharging if you dont run anything else in the trailer?
It may be a lot better than I am guessing, but I really do wonder if there is an optimistic answer.
That there is a self sufficient method is a positive, just curious if the method would be real world useful.
Aug-16-2019 05:51 AM
RoyJ wrote:Reisender wrote:wanderingaimlessly wrote:
For the electrical engineers that really want to get into the weeds on this, real question for you.
IF you had a Tesla truck and TT and ran out of power in the desert southwest. And you had a trailer with 400 watts of solar, and a 430 Amp/hr battery pack. Along with a 1500 watt inverter.
How long would it take to generate enough power to get the truck, without the trailer, 20 miles, to a real power source for recharging if you dont run anything else in the trailer?
It may be a lot better than I am guessing, but I really do wonder if there is an optimistic answer.
That there is a self sufficient method is a positive, just curious if the method would be real world useful.
Well, a kw will take you about 6.7 km in our cars. So 30 km is around 20 miles. So let’s say you need 5kw total. I’ll leave it to someone else from there.
I'm going to guess it takes from than 1 kwh to drive 6.7 km when TOWING.
Let's say you tow at a very conservative 90 km/h, or 56 mph. It takes 0.0744 hrs to drive that distance. Your average power output would be 1kwh/0.0744hr = 13.42 kw, or 18.01 hp.
There're very few trailers you can tow with an average of 18 hp.
Drag = Cd*A*rho*V^2/2
Assuming a small 7' wide 8' tall trailer, your frontal area is 5.17 m^2. The combined Cd of a truck and trailer would be lucky to hit 1. Rho of air is roughly 1.2. Plugging in the numbers, drag at 56 mph is:
Drag = 1973N
Power = F*V = 1973N x 25m/s = 49.33 kw, or 66hp
In conclusion, the required power is far greater than the 18hp assumed. Re-calculating with 66hp, it takes 49.33 kwh to drive 56 miles, or 1.13 kwh per mile. A 1.5kw generator + 0.4 kw solar makes 19 kwh in 10 hours, assuming PERFECT charging.
You can tow 21.47 miles after 10 hours of generator + solar. In real life, with charging inefficiency and less than 10 hrs of perfect sun, you'd be lucky to get 15 miles.
Aug-16-2019 05:37 AM
afidel wrote:
I'm hopeful that my retirement tow vehicle will be a used Class 8 electric truck. The Tesla semi is now testing at 600 miles for the full range model with a 75k pound payload (albeit jersey barriers so way less drag than a 5er) link
Aug-16-2019 12:27 AM
Reisender wrote:wanderingaimlessly wrote:
For the electrical engineers that really want to get into the weeds on this, real question for you.
IF you had a Tesla truck and TT and ran out of power in the desert southwest. And you had a trailer with 400 watts of solar, and a 430 Amp/hr battery pack. Along with a 1500 watt inverter.
How long would it take to generate enough power to get the truck, without the trailer, 20 miles, to a real power source for recharging if you dont run anything else in the trailer?
It may be a lot better than I am guessing, but I really do wonder if there is an optimistic answer.
That there is a self sufficient method is a positive, just curious if the method would be real world useful.
Well, a kw will take you about 6.7 km in our cars. So 30 km is around 20 miles. So let’s say you need 5kw total. I’ll leave it to someone else from there.
Aug-15-2019 07:32 PM
ShinerBock wrote:wilber1 wrote:
It would only be able to make a prediction after you started towing and it knew the actual energy consumption. To make any kind of prediction in advance it would have to know the weight of the trailer and its drag coefficient. Yes, you would get an idea from experience.
This is why I still say EV's have a very long way to go before they become the dominant choice for tow vehicles. It is not as simple as most think, and these obstacles need to be addressed. Some can say that they can just add a larger battery in the trucks, but that will also add weight(and costs). Trucks today are already maxed out in there government regulation classes as it is and making them heavier would lower their rated capabilities even more. You would likely end up having an EV truck with a GVWR in Class 3 one ton, but with the capabilities of or less than a Class 2A half ton.
Aug-15-2019 09:26 AM
wilber1 wrote:
It would only be able to make a prediction after you started towing and it knew the actual energy consumption. To make any kind of prediction in advance it would have to know the weight of the trailer and its drag coefficient. Yes, you would get an idea from experience.
Aug-14-2019 08:52 PM
time2roll wrote:wilber1 wrote:Supposed to learn based on your driving style but this would need a software update to get a more accurate estimate at the start. User would quickly learn to divide by 2 or 3 depending on conditions.
Does it know if you are going to make it towing a 4000 lb barn door? What I got from those videos is that it doesn’t. I think those videos made a good case for a plug in hybrid with a good size battery, so you can take advantage of the electric motor torque on grades but not worry about being stranded.
About the same as a petrol truck where the DTE says 450 miles and you hook up a trailer and know very well you only get 225 miles range.
Aug-14-2019 06:12 PM
Aug-14-2019 04:56 PM
wanderingaimlessly wrote:
For the electrical engineers that really want to get into the weeds on this, real question for you.
IF you had a Tesla truck and TT and ran out of power in the desert southwest. And you had a trailer with 400 watts of solar, and a 430 Amp/hr battery pack. Along with a 1500 watt inverter.
How long would it take to generate enough power to get the truck, without the trailer, 20 miles, to a real power source for recharging if you dont run anything else in the trailer?
It may be a lot better than I am guessing, but I really do wonder if there is an optimistic answer.
That there is a self sufficient method is a positive, just curious if the method would be real world useful.
Aug-14-2019 04:34 PM
Aug-14-2019 04:14 PM
ShinerBock wrote:Reisender wrote:
Good question. I’ll do some snoopin. The ability to enter that kind of data would be kinda cool.
The ability to even have that information for every trailer out there would be cool, but highly unlikely.
Aug-14-2019 04:14 PM
wanderingaimlessly wrote:
"Hydro has a place too, as well as being tied to flood control, irrigation etc. Wind as well. "
yeah they do, but how do you put them in your back pocket and take them with you?
Sails being put up will be cool.
These new high tech trucks are sounding more and more like a Mad Max Movie.
Yes, I'm just having fun with this.