MemberAugust 29, 2021 at 6:33 pm
Funny frankly, how timid those opting for the radical change to electric powered travel are. They’re even more timid than Ford Motor Company :), an institution known more for Henry Ford’s “any color as long as it is black” statement than radical change. I mean Ford was the last to walk away from the front-engine, rear drive car format adopted in what, 1910?
Seems Ford has filed a patent – it is obviously very broad – that calls for towing arrangements for EVs that take into consideration roadway charging.
The Ford Patent involves choosing times when the towed vehicles regen would be energized. https://www.thedrive.com/tech/41529/ford-looking-at-charging-evs-by-flat-towing-them .
I remember a youtube video four or five years ago that put a tow chain on a Leaf and the ensuing pull around the parking lot was shown to be able to charge the vehicle. Went to check if I could see it and this bit showing a Model 3 driver behind a MB sedan being pulled at up to 70 mph, charged from 15% to over 50% in a 20-mile (20-minute) run tethered to ICE sedan. The problem was the MB got about 5 mpg during the exercise as the ‘power expended’ to pull the Tesla in full regen was about 87 hp on top of the energy needed to attain that speed.
What Ford’s patent suggests is that you need to electronically couple the vehicle to the tow vehicle and manipulate the power from the towed vehicle to minimize braking drag from the regen; opting for full regen when descending a hill or other breaking situation.
All moderan EVs offer regenerative braking and all EVs can gain a charge through this process.
I suspect the reason that EV manufacturers have literally shunned this idea is because they were afraid of the liability they may incur if, say someone tows an EV for an extended period it will stress both the tow vehicle enormously and potentially cause an overheating/charging problem with the towed vehicles battery overheating … with constant regeneration.
I think Ford’s realization with its patent is that you don’t want the towed vehicle to invoke full regen with maximum braking at all times. For instance if you were towing my spark EV, you would use the lighter regen of the car in D rather than in the enhanced regen capability of “L” … and you would be in a towed formation for a longer period of time – not the 20 minutes of the Tesla driver here: https://www.youtube.com/watch?v=nILM_DEdBqM
I’m sure the average human being could devise numerous ways to make towing for a charge a disaster from over-towing, over-charging or just some other element of stupidity but the basic law of physics that make regeneration possible operate independently of whether a tow-rope/chain is attached to your car.