Earlier quoted context omitted.
Not true, a rope is fine.
Until the tow truck hits the brakes…
I was once involved in towing a car using a partially-inflated water bed as a 'bumper'. We got there!
Towing a Tesla at 70 MPH replenishes battery at fast charger rates
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Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates
#132They would clearly have been better off putting a diesel generator on a trailer behind the tesla, for fuel efficiency. 4 gal in 20 minutes the video said? That's about a 160kW generator https://www.hardydiesel.com/resources/diesel-generator-fuel-... I wonder how diesel generator + tesla compares to an actual diesel car.
I've sometimes wondered if it would be viable to build a "range extender" for electric cars which is basically a generator which is designed to integrate with the vehicle, but can be easily removed. Then people could fit them when they were going on longer trips converting the car to a plug-in serial hybrid. Car dealerships could perhaps rent them out and do the install/removal.
Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates
#133Earlier quoted context omitted.
Teslas have no resistor banks? A great omission.
Why would a resistor bank be better than mechanical brakes? Both get rid of excess power as heat, and you probably need the mechanical brakes anyway.
What is implied by the GP is that the cost of ownership for regenerative brakes is lower per joule.
That's obviously true when that joule is "reused" and not so obvious when it's dissipated. Mechanical brake pads have to be replaced but I assume there is wear on the (more expensive?) parts in a regen system too.
Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates
#134The most spectacular example of regenerative braking are trains that are used in Scandinavia, heavily loaded with iron ore that is transported to the coast: "In Scandinavia the Kiruna to Narvik electrified railway carries iron ore on the steeply-graded route from the mines in Kiruna, in the north of Sweden, down to the port of Narvik in Norway to this day. The rail cars are full of thousands of tons of iron ore on th…
I’ve seen something similar to this with large dump trucks made for hauling loads down mountains. They generate so much power fully loaded on the way down that they can make the trip all the way back up.
Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates
#135Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates
#136It seems like the tire wear wouldn't be worth it. You're pulling the tires at almost 100 horsepower of energy transfer. Sure, neat for a video gag though.
Hah, don't try it in Europe either, max towing speed in Europe is 40km/h or 25mph. I guess a tow truck with a bed that has a rolling road would be an idea, prop up the car so the weight of the car isn't actually exerting force that makes the wheels harder to turn/cause extra wear. Or the "rolling road" can be replaced be a contraption that attaches to the wheels by e.g. its rims, and spins it.
This would work but it would probably make more economic sense to carry a generator to the car than to carry a wheel spinner gizmo.
Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates
#137What if you had two Teslas taking turns towing each other at 70 MPH? You could increase the range to (INFINITY*EFFICIENCY)-MATHS! That's a lot of muskjuice.
Why stop there? You could get a whole circle of Teslas towing each other and never even have to stop moving!
Then, have them turn a turbine to generate electricity, qed.
Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates
#138Earlier quoted context omitted.
Teslas will switch to friction brakes when regeneration limits (peak current or battery SOC) are exceeded. I’ve sustained constant 50kw regen while downhill through Appalachia passes, no issues, with the caveat that regen current is limited if the pack is cold until it approaches operating temperature (yellow dashed lines on the regen current display indicate your reduced regen capability).
Teslas have no resistor banks? A great omission.
A resistor bank of the required wattage would simply be a big lump of dead weight most of the time. And it would need its own cooling fan which would add even more weight.
Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates
#139Earlier quoted context omitted.
And even better just embed some wires in the road and charge everyone at highway speeds. Either ground-level power supply through conductive rails or inductive coils both work with different tradeoffs. https://en.wikipedia.org/wiki/Electric_road
> Just embed some wires in the road... No offense but that is the most loaded phrase I've heard this week. That would be a major overhaul of both roads and electric car designs.
Sure, but it would be worth it.
The cost is that you'd have to re-engineer maybe ten or twenty percent of major freeways and interstates (like have two miles of charging per every ten to twenty miles of regular road), and you'd need to establish a standard for trucks and passenger vehicles and get automakers to adopt it. (Or make it simple enough that it can be added as an aftermarket kit.) You'd also need to install more electrical generation capacity. (Fortunately, charging cars while they're driving shifts most of the charging from nighttime to daytime, when solar power can be used for this purpose.)
The benefit is that you could reduce long-haul trucking fuel consumption to near zero and reduce the need for EVs to have heavy, expensive 200-mile-or-more-range batteries.
Re: Towing a Tesla at 70 MPH replenishes battery at fast charger rates
#140Earlier quoted context omitted.
It’s likely fine, 65 kW is only ~85 HP. Simply maintaining highway speeds is ~25HP, so as far as the tire is concerned it’s the equivalent of mild acceleration or breaking. The regenerative breaking system is likely designed for long mountain roads, so it might overheat but probably not.
Teslas will switch to friction brakes when regeneration limits (peak current or battery SOC) are exceeded. I’ve sustained constant 50kw regen while downhill through Appalachia passes, no issues, with the caveat that regen current is limited if the pack is cold until it approaches operating temperature (yellow dashed lines on the regen current display indicate your reduced regen capability).
Does this mean that when the battery is full you must use the brake pedal? Or does the software automatically apply the friction brakes when you back off the accelerator?