Total fuel economy of towing a Model 3 with a Ford Raptor

Firstly: can you charge a tesla by towing it?

Secondly: Is it more fuel efficient to just drive an ICE raptor alone, or use the Raptor to charge the Tesla and then drive the Tesla? The answer may surprise!

[youtube]RaGVoB4Zn-Y[/youtube]

Works with a Bolt too.

https://youtu.be/JDLsKGNgOEE

I like that EE yt channel engineering explained, he actually made it into a Car & Driver magazine I was reading today.
I assume the EE in the pic/vid is the same thing, I remember seeing that on yt but I watched how the F150 - Tesla tug of war was a scam, f150 2wd, tesla 4x4, EE goes through all the angles, great channel.

I would take that Raptor straight back to the dealer.
69L/100k at 30km/hr , towing on a flat track. ... ??
Even 22L/100km “ normal” driving is a joke !

Punx0r said:

Secondly: Is it more fuel efficient to just drive an ICE raptor alone, or use the Raptor to charge the Tesla and then drive the Tesla? The answer may surprise!

Click to expand...

I am not surprised. Much of the engine inefficiency in a typical ICE is caused by pumping losses; trying to suck large amounts of air past a partially closed throttle plate. By towing (operating with a bigger throttle opening) engine losses per HP are reduced. Normally this goes to overcoming wind resistance, which goes up by the cube of speed. This is why going faster always causes lower MPG, because the gain in engine efficiency is overwhelmed by the power needed to beat back the air. But at lower speeds, being able to operate with a wider throttle setting (and having that extra power go to something useful, not just air friction) reduces losses overall.

I came a similar conclusion after a bit of initial head scratching. The huge increase in fuel consumption of the raptor when towing the tesla does demonstrate how powerful the regen is. I'm guessing it must be around half the maximum possiblr braking effort with the mechanical brakes.

Simple logic would suggest that if it is regen’ing at the rate of 1kWh per km, whilst being towed at 30 km/h, then that would be equivalent to a “charge” rate of 30kW.
The lap was 1.4km, so they should have charged 1.4kwh ?..(1.0+ kWh at least)
How come they only managed to drive one 1.4km lap on that 1.0+ kWh ?..doesnt the M3 only consume <0.2kW/km ?
That implies a total range of less than 140km (< 90ml). On a full pack at that rate ?
Am i missing something here ?

PS 30kW of regen seems a lot less than the system should be capable of. ( pack can be charged at 250kW)
If it takes 200+ kW to accelerate the M3 up to 100kph in 5 sec, it would need a similar power to stop it again in a similar time (reasonable ?)
So either regen can be much greater, or the mech brakes do the work.

I'm no efficiency expert but surely it would have gone further if they crept around at say 30km/h.

I believe model 3's most efficient speed is 25mp/h or 40km/h??
Accelerating hard to 150 is stupid way to drive efficiently - pretty basic stuff with losses from wind resistance.
Lose some energy in heat when straining batteries and motor.
Ah but you'll gain some of it back thanks to regen in the corners, well you'll only gain about 60-70%* of that braking energy back.
That's IF you do all your braking before the corner, braking through the corner will incur greater losses.
Speeding in corners will result in loss of speed/energy/range. Goodbye kinetic energy, curse you friction.
Well, I guess, thank you friction, we'd like to actually turn. :lol:

*No idea what the efficiency for model 3 is exactly but I wouldn't imagine it won't be that much different unless they've found exciting ways to break the laws of physics - I live in hope.

Accuracy of this test?

boars said:

: ....
*No idea what the efficiency for model 3 is exactly

Click to expand...

“Efficiency”. Is a tricky concept,.
People like to compare EVs using Empg (equivalent mpg)
In steady driving, as they did (40-100km/h). to estimate their power consumption (193 W/km), the M3 is equivalent to about 120 Empg.
But driving as they did after the tow, it consumed 1000 W/km which is more than 5 times its lower speed result , or around 23 Empg.

In this instance, I was specifically referring to having no idea as to the efficiency of their regenerative braking, apologies if that was unclear.
Not in relation to how far they can get or why they were getting horrible results while driving stupidly.

Empg should factor all these things in, my "*" was for one aspect, not all of it.

You cannot expect a best case scenario when driving wildly above general use.

¯\_(ツ)_/¯

Looking at it from the was they are producing the regen power by towing with the raptor.
The raptor used 69l/100km towing, and 22 l/100km on its own....
So you could say the regen of 1kWh per km was using 0.47 L of gas , (69 - 22 = 47l/100km)
And since a litre of gas is equivalent to 9.0 kWh, ..then that 1kWh needed 4.23kW of energy to produce .
Hence about 24% efficient ?
However , that figure includes the energy needed just to tow the Tesla along,..
..they should have measured the Raptor fuel consumption towing the tesla without and regen to measure that portion of the extra fuel use.

But of course, in normal use, regen braking needs no external energy (other than kinetic) so its efficiency is effectively infinite.

Sadly the supply of kinetic is not unlimited or infinite (without battery loss), hence my musings on the efficiency of kinetic to battery efficiency.
The videos figures are about as accurate as a Top Gear episode - entertainment first, still fun to watch though.

Sure, certainly not definitive.
all they showed was that ..
..You can charge an EV via regen by towing it..
.. The Tesla M3 burns 1kWh per km when driven fast...
..the Raptor’s fuel consumption is a joke ..even when its not towing !