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As a trained diesel fitter and confirmed petrolhead, I remain to be convinced by the case for EV’s, but as an engineer, I’ve been pondering the technology behind them and have two questions. If anyone can provide answers, I’d be obliged.
1. On an ICE, the batteries are charged by a standard alternator so why is there not a similar system fitted to EV’s? If it were driven off the drive train, it would at worst provide a top up and/or power the vehicle systems such as lights, wipers, heater, etc. At best, particularly on long journey’s, it could recharge the battery.
2. Given the power generated by wind has become a standard source of energy, why are wind turbines not fitted to EV’s? I’m not talking about windmills on the roof, but a simple unobtrusive device akin to a Dyson blade working in reverse and using forward momentum to power a generator. It could be fitted behind the grill or even underneath the vehicle.
Current car: Mini Countryman EV in very shiny black!
Previous car: MG HS Exclusive in nice shiny black.
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On your 1st question, most if not all EV’s have 2 batteries, the main traction battery and a standard 12v one. The traction battery is recharged either by plugging in or regenerative braking and powers the motor and A/C only. The 12v one though is charged like it is is an ICE via an alternator. This battery usually covers all the traditional tasks of a car battery, with the exception of the Air conditioning.
The second question, I would guess that the extra weight and cost of such a system, just isn’t practical for the amount of power it could provide. The most logical (to me) system would be fitting cars with solar roofs, I believe the Hyundai Ioniq5 has this as an option, but for some reason not a UK one.
Previous Motability Cars
2006 - 2009 Skoda Superb VR6 2.0tdi
2009 - 2012 Citroen C5 2.0tdi VTR Nav
2012 - 2015 Nissan Qashqai 1.5dci tekna
2015 - 2018 Ford Kuga 2.0tdi Titanium X
2018 - 2021 BMW 220d X drive 2 Series Active Luxury
2021 - 2023 Hyundai Kona Electric Premium SE
2023 - Hyundai Kona Electric Ultimate
Probably best to email the technical department of Tesla to get proper answers but in my best estimate….
1. It isn’t needed because it sort of already does, the 12v is charged from the traction battery, the traction battery gets some of its charge through regen. Plus it only needs to top up the 12v when it’s required. With an ICE there is no other way to recharge the 12v than when the engine is running but you are constantly running the alternator so for 90% of the time it is an unnecessary drag on engine power.
2. Probably the financial costs but I doubt it’d get back the energy it lost in extra drag… EVs are already very efficient and an external wind turbine isn’t going to help when most people aren’t going very long distances. Some folk reported economy gains just by blocking up the small vents at the front used to cool the aircon radiator, for serious distance or speed attempts they’ll tape over any panel gaps too while opening a window even a fraction causes a huge aerodynamic drag.
Both of these ideas may have a use in another setting but I doubt it’d help with a regular user just going to work, shopping, visiting etc.
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