Designing Electric Cars to Waste Energy? Why & How

[@NeilBlanchard]

Having driven EVs for about 10 years in a place that has cold winters (New England) - by *far* the most efficient way to warm the occupants - is to heat the seats, and the steering wheel. And by FAR the most efficient way to defrost the windshield and mirrors etc - is to directly heat them. The windshield can have a very thin (like a few molecules) layer of silver in the glass, and you can very quickly defrost the whole windshield for a few hundred watts. A heat pump is the most efficient way to warm the *air* in the vehicle - and when you have good seat heaters and a direct heating windshield - then it is actually quite rare to also need to heat the air. The engineering mindset for ICE vehicles is wrongheaded for designing EVs. In ICE vehicles which waste 70-75% of the energy in the gasoline - you have tons of "free" heat, so heating the air to then heat the people or the windows - doesn't matter. But, by heating the things that need it *directly* (avoiding the lag time and inefficiency of transferring the heat to the air - you are most likely *far* better off than trying to come up with ways of wasting energy to make heat to then gather it up and then distribute it.

[@electrarc240]

Couldn't agree more, just like a heated blanket instead of central heating!

[@ABaumstumpf]

That sounds more like they are trying to reduce the number of easy repairs and increase the reliance on "certified" shops.

[@electrarc240]

Sad. I am planning on buying a cheap EV when I next have the chance, to make videos to show that they really aren't hard to work on (and modify😏). DIYers and garages all seem scared of them but they are much simpler than ICE car

[@ABaumstumpf]

@@electrarc240 Depends on the brand and what you want to do. Some have had made some rather lets say infamous decisions about disabling features when parts were replaced by non-licensed shops.

[@electrarc240]

@@ABaumstumpf Yeah so sad that many manufacturers are taking the change to EVs as their opportunity to introduce all this software locking crap from the tech world. My plan is to strip it all out, cause really the basics that you need to drive and be roadworthy are very achievable even with all custom electronics. Minus a ton of the reliability of course, and the paperwork if you decide to tell the authorities about the "adaptations" hehe. But a fun project I hope

[@sandwich.entity3810]

​@@electrarc240love this idea, I hate how software locks are being introduced more and more. Also how everything is becoming a subscription

[@stellamcwick8455]

@@electrarc240 , I have been waiting for someone to do this.

[@humanlike6658]

The heat pump is beyond competition

[@cerulyse]

Yes they work down to well below zero and cheap skate on a smaller battery😅

[@electrarc240]

I agree, makes so much more sense

[@orbatos]

Cane to say the same thing. While researching the ideas on the video is interesting it's barking up the wrong tree entirely and will never address the needs of more extreme climates.

[@1943vermork]

In very cold conditions, you need some extra heat to start the heat pump cycle. Tesla is running their compressor loop in a weird configuration for that very reason. So the electronics inefficiency avenue could be another strategy

[@thefatmoop]

Its trivial to dissipate heat in the stator of a induction or bldc motor without generating torque... thats a much better route. Since approx 2021 teslas can waste heat in their motor/inverter and pipe the coolant through the heat pumps cold side. This is done when the outdoor temp is too cold for the heat pump

[@poprawa]

It is also done if supercharger is navigation destination and ETA is close enough to use heat pump and extra heat from drive units

[@electrarc240]

Ah very interesting, yeah the motor is certainly the easier place to add losses

[@stellamcwick8455]

I realize the goal is to reduce total component count but im wondering if its worth it to run the inverters like this. I know its not sexy but just reversing the flow of the already supplied AC cooling system provides a fully functional heat pump heating system too. The bonus is that since most automotive HVAC systems are just pre designed products from third party manufacturers, they achieve economies of scale cost savings. Im stuck on efficiency benefits. Using the inverters is akin to using a resistance heater, just in a different form. Heat pumps are a more efficient method of moving energy from one place to another. When range and battery efficiency are important considerations, does it make sense to do this? Are they just trading one problem for another?

[@arduinoguru7233]

Sorry, aren't two wires short-circuited not considered electric heater? how simpler they want it to be?

[@00000005547]

@@arduinoguru7233 resistive heaters are very inefficient as they only produce 1W of heat per 1W electrical power consumed. A heat pump system ie an air conditioner can consume maybe 1000w of electrical power to move 3500w of thermal power from inside the house to outside. Reverse it and you get a heater that is multiple times more efficient than the resistive counterpart.

[@arduinoguru7233]

@@00000005547 Ok, I was talking about theirs reasoning of reducing parts 00:08 by throwing out resistive cabin heater, and using inverter heat loss as source. Unless they add a heat pump to the inverter, I don't think they'd changed anything or reduce the part count

[@stellamcwick8455]

@@arduinoguru7233 , I think I see what you are saying. Its my point as well.

[@electrarc240]

Yeah this is exactly what I said to the guy, but he assured me this is something being considered. Does seem odd as running the inverter at higher temp is going to reduce its life. Maybe that is seen as a positive...

[@swrekcfest]

Nice way to add the subscribe pitch 👌👌😂

[@xFlow150]

Very interesting video! I never really considered any of this as you've proven once again that my knowledge of FETs is quite lacking.

[@user-mc6dg6qe8l]

Heat the seats steering wheel and windshield directly, heating the air is a luxury.

[@Levibetz]

It's an interesting concept, but aside from the efficiency issues, I don't see how it would be practically implemented. A typical automotive heater core is running at engine coolant temperature, about 90c. My understanding of batteries and inverters is that they run closer to room temperature. So the heater core will exchange less heat on a cold day because the temperature gradient is less than if the core was at say 90c. Of course you could cook an IGBT up to 90c, but then you're running that whole coolant loop at that temperature which stresses every component in the loop. Alternative is make a separate loop, but now complexity is returning to the system just to make the IGBTs work hard for no reason.

[@electrarc240]

Yeah in terms of actually getting the heat to the cabin I have no idea what they are planning

[@InfinionExperiments]

I believe the strategy is geared towards heating the batteries, which heat is directly conducted to the cells via coolant jacket at a lower temperature. The only reason for high temperature cabin heat is because we don't have a coolant jacket of our own and must have that heat delivered through air, which has very little heat capacity, is mixed and spread out over several feet before getting to us.

[@Levibetz]

@@InfinionExperiments Oh yeah that would make much more sense.

[@josepheccles9341]

You simply adapt the circuit that drives the MOSFET. You drive them from a buss with multiple voltage settings.

[@DjMarik78]

They would have to waste the same energy in the power devices that would be otherwise invested in resistive elements for heating. So what's the point? Waste energy to get rid of the resistive elements? And don't get me started on the reliability issue, which would be severely compromised, for many reasons... PS: What would make more sense would be to keep going after the highest efficiency possible, but what ever power does get wasted in heatsinks, use it, harness that heat, channel all of it inside the heating matrix, combine it with the usual resistive heating elements, but invest less power on them, just because you use the heat already generated on the power devices. This, to me at least, would make much more sense, using what you already have, and still increasing overall efficiency.

[@Bvv4529]

Thank you so much for your videos. I appreciate your efforts, your way to explain it. I've watched them all, some of them twice 😀

[@jannejohansson3383]

Use peltiers in system, so you could cool components and those give cooler coolant plus eat some power, giving heat in fluid system and to cabin. Remember you could add resistive heater, that have 100% efficiency.. I would use A/C and use it for cooling or heating cabinet. Make it work with CO2 fridge rant. Or use two coils to turn motor forward and single coil backwards, then you get some heating components.. And system could adjust it, without driver feeling anything. You could run and breaking 3~ motor same time... There's many ways to do this, but I would use different system that moves heat away from cabin or to in it. That system compressor must be controlled different speeds by the need of heating or cooling. Just turning it on 100% and off some time and back on, that's out of option today. Usually those systems working in best efficiency at 60-80% compressor power.

[@alexwang007]

I personally like the method of increasing the f_sw the most, and i feel like you could enhance the loss slightly by using a core material that has more losses at higher frequencies, or use DC current bias and drive the inductors slightly into saturation.

[@4bSix86f61]

This is like purposely compressing music to make it sound better. One day those mosfets WILL FAIL and those 'certified' shops will have a lot of fun. Mini heat pump system is more efficient than driving silicon with low quality signals.

[@4bSix86f61]

Heat Pumps underrated. Don't even think about peliter modules.

[@HughCStevenson1]

The gate characteristics are quite variable so the power loss would be too variable to be useful.

[@sleepwalkerbg1]

So basically , you have a solution around which you create a problem 🤣 Car manufacturers did it again. One cute fact is that lifespan of capacitors depends of twmperature so while you use your mosfet "heater" , other surrounding components suffer :) Niceee 😎 On the other side - video is great and very educational. Good job & thanks!

[@gregwmanning]

Why not keep max efficiency and have a cheap simple 100% efficient resistor mounted in the car that requires less ducting to provide heat when its required?

[@chrisharvie-smith486]

Because a heat pump can give 5 units of heat from 1 unit of electricity. It's the heat you want with the best range. For easy losses just increase the switching frequency so more time spent between off & on where there are more resistive losses.

[@TheBlibo]

It sounds to me that making an inverter deliberately less efficient is another over-complication that is likely to cause more unreliability, by all means harvest the heat from the battery, inverter and motor but keep the resistive heater it's simple and works. The problem of integrating everything is that when one part breaks the whole lot is compromised. The best way to heat a cabin is to harvest the hot air emitted from politicians

[@electrarc240]

Love that idea, definitely plenty to go round!

[@drbone4287]

Really interesting topic. I like original approach to the stuff

[@lucabarbolovici4974]

The "goodnight" at 13:41 is so cutee❤

[@davidthomas1356]

They don't have diagnostic capabilities to diagnose electric now, now ad more ? Brilliant

[@gregreynolds5686]

Great experiments! Of course, the cynic in me thinks that automotive interest is to reduce the longevity of the power transistors due to increased thermal cycling...

[@electrarc240]

I think that is what most of us are suspecting unfortunately

[@james10739]

Wouldn't that be the same amount of power just with additional wear on the inverter vs the heating element

[@electrarc240]

Yup...

[@poprawa]

Major EV manufacturer uses loosy mode of motor driving (lets just say stalled motor) to heat up the batteries, but only in scenario where range is irrelevant - that scenario being ride to DC charger. Heat pump still produces heat in that scenario, but 5-10kW extra comes from drive units

[@electrarc240]

Interesting!

[@kabandajamir9844]

So nice thanks sir

[@arduinoguru7233]

I can't get it, aren't two wires short-circuited not considered electric heater? How simpler they want it to be?

[@nikolaskallianiotis8622]

So you are taking an EV which already suffers from shorter driving range compared to ICE and you waste additional power from the limited you have to heat the cabin. To me this looks plain stupid approach, actually the whole BEV concept is stupid as long as we have no batteries' chemistry that can store huge amounts of energy in the smallest possible volume. Heat Pumps are efficient only in climates where there are no extremes in temperatures between seasons or day and night. People think that heat pumps are like magic or supernatural technology, but it's just a heat exchanger which consumes power in order to do its thing and only under favorable conditions can be efficient.

[@FLORIDIANMILLIONAIRE]

Tesla is already doing it in model 3 with their space age heat pump

[@MyProjectBoxChannel]

This concept reminds me of when people were using waste heat from bitcoin mining rigs, to heat their homes. And with all the heat generated from generitive AI chips, it could be used for communal heating in small villages in in colder climates. If you have wast heat, then put it to good use 🤔👍. It's clever to get cooling and heating from the same device! Just by dialing the efficiency up and down😮

[@brianransom16]

Watts the efficiency of this. Same as resistive I assume. Would it not be more efficient to modify the AC to produce heat as it can produce more than 1 watt of heat per watt used? Half of engineering in the automotive industry is complete garbage, always looking for backwards ass solutions which end up screwing over the technician in the long run. Ask any mechanic. Also support right to repair.

[@AlaskanInsights]

They should just switch to linear power supplies... yuo can put a cushion on the transformer and keep your rear end warm. LOL.

[@electrarc240]

Linear regulator for 12V system.

[@miltonthecat2240]

This reminds me of those "slew rate controlled" power supply controller IC's to reduce noise in power supplies for sensitive circuits, trading off lower efficiency for lower noise. But I have to agree with the other comments that the better solution seems to be adding a reversing valve to the A/C system to create a heat pump. Given how quickly the failure rate of semiconductors increases with temperature (2x for every 10C?), this seems like a dumb approach. Heated car seats? No thanks, what an unpleasant feeling!

[@electrarc240]

Yes definitely for the heat pump. I agree on the heated seat, why would I want to still be cold but have a sweaty back??

[@1kreature]

Or, just adjust the drive of the motor which is also cooled.

[@jagmarc]

Isn't a lot of energy lost anyway throughout the whole entire electricity supply chain? Not every kWhr generated at the power station actually makes it to the EV. The HT HV lines are air cooled and heating up the environment.

[@honeydavis5568]

How ridiculous. Try adding a resistance heater. That is fewer parts than modifying the inverter. The way to lower the part count is to get rid of: electric door locks and windows, the screen in the dashboard, ABS brakes, the electric mirrors. That's a start.

[@jimviau327]

There is nothing more efficient than a resistor at losing energy into heat. Why going through such shenanigans and headaches?

[@electrarc240]

I know right...

[@MariadeLurdesMelo-bx5vz]

👍

[@martin_soerensen]

Not a very good advertisement for your sponsor when one of the boards have two pins shorted on the IC.

[@electrarc240]

That was my soldering, it is on the address pins to set the address. Theirs is flawless

[@TradeWorks_Construction]

Very interesting idea and thought experiment to try and put into practice. That said can I bitch slap some common sense into the enginerd or whoever you were speaking with? It would really make my day! WHY ON EARTH would you ever intentionally increase the #1 killer of all circuitry?!! Why not just use a radiator and fan and use the fluid used for cooling the electric motors? I can’t think of any reason other than manufacturer saving from removal of what they are already using. Either way you’ll need venting and a fan so you save the cost of a small radiator and tubing so like $100 …. all at the cost of risking the heart of the system. 🧐 Oh I just answered my own question, any future costs after warranty are all on the consumer so any production savings stay in their pocket and they build in planned obsolescence as shorter lifetime for the inverter which will continue justifying production and sale of inverters in the future. Can I please repeatedly face puch the guy considering this until I break my hand? I swear even after the pain and doctor fee’s, doing so will make my year.

[@electrarc240]

Lol, but I understand your feelings haha!

[@DaisyMao-o9c]

like it ! 🤩

[@LoganDark4357]

pls get pop filter

[@electrarc240]

Doesn’t it feel good? 😉. And yeah I have considered it but I have my mic on my bench and move it constantly so a pop filter would be very intrusive. I think a lavalier mic would be better but idk how to pick a good one. Cause I already struggle with volume changing every time I move and that would fix that

[@LoganDark4357]

@@electrarc240 feels startling. because your voice is usually audible but then the ground jumps underneath me. like a thump. lol

[@ninefox344]

Why would they do it this way when they can just run the AC in reverse?

[@koharaisevo3666]

The outside is too cold.

[@ninefox344]

@@koharaisevo3666 Modern heat pumps are good to like -20F or worse. Example youtube video: wCZrBI3PFag (Put this after v= in the youtube URL)

[@stellamcwick8455]

@@koharaisevo3666 , newer vehicle heat pump systems, like their building counterparts, are designed with efficiencies that allow them to work down into the single digit temperatures (F) and slightly negative temps (C).

[@ABaumstumpf]

@@koharaisevo3666 "The outside is too cold." At that point it is too cold for electric vehicles in general.

[@00000005547]

@@ABaumstumpf Nailed it. If it's too cold for a heat pump to work, chances are your battery pack is consuming half of its stored energy just to keep itself warm enough to be used.

[@mmuller2402]

Still stupid as Tesla already uses the engine heat while rotor is locked... zero extra part just software, why load the complex inverter and kill capacitors with heat when the cooled rotor can do it?

[@Gary_Hun]

Running components at much higher temperatures, that are supposed to be rather cool, for a heating effect. Shorter component life while cheaper to produce, brilliant consumerism crap poisoning already the just blossoming, already not even remotely green EV industry. Why am i not surprised.

[@electrarc240]

It is a rather tragic state of affairs...

[@analoghardwaretops3976]

Redesign the car on the likes of an electric 2 wheeler...that has multiple pedal assists for...the driver , &/or all of the occupants pedalling to stay sufficently warm....the entire vehicle does not need to be warm & cosy..... when occupants are " comfortably warm"....,it switches to the normal vehicle driving mode...& back again...to pedal assist when/ before anyone or more gets... un"COMFORTABLY NUMB" chilling in there...😂😅😊.. Fuel/ batt.charging energyy saved..is now..more food calories for recharging up one's own power bank... " HAPPY HOURS" will always come around..😅😅😅😅

[@johansvideor]

As an EE. This is just silly.

[@electrarc240]

Oh I completely agree! Was fun to play around with though

[@RaoulEvilD]

Man, THAT for SURE is such an incredibly BAD idea to invest time, money and brain power in. But for sure this world wouldn't be as "entertaining" without a bunch of those irrational products/features/decisions to proactively rant about or retrospectively cry about 😅.

[@MartinSBrown-tp9ji]

This is modern day engineering and in old days practical engineering rely worked, This is not practicable. Chips are not that reliable in mechanical controls. To much learning from using a computer and not (wisdom) reality engineering. Example , Bowing Aircraft. (dumb college training.) No wisdom in modern day training.

[@electrarc240]

I agree

[@Mr.Leeroy]

Is it just me or all these random EV topics trending in general EE media is just like all the AI buzz in computing?

[@electrarc240]

Not an EV fan? I didn't realise it's "on-trend", I haven't seen much myself, just been an EV enthusiast for many years.

[@Mr.Leeroy]

@@electrarc240 I was not hating it, nor rooting for it, completely neutral. But the more you see it, the more it seems like a very mildly interesting click bait type material that is aiming to feed on procrastination traits. And there is an increase in EV content last few years. This video is not that though, as you did a great job staying away from "motory" specifics and concentrating on pure EE basic concepts. On the contrary, it was not boring, largely because test subject was a generic Buck circuit and not a terribly specific niche EV thing.

[@VEC7ORlt]

Now there is dumbass way to do things. Also heat pumps exist.

[@electrarc240]

Lol

[@VEC7ORlt]

@@electrarc240 yeah, lets stress most important components in stupid ways to generate heat instead of using a dedicated and more efficient way or easier and straightforward way.

[@electrarc240]

@@VEC7ORlt Gotta love "high reliability" design...

[@johnwest7993]

Without watching your video, gate frequency seems to me to be the obvious best way to go. But I don't like the idea of adding heat to the motor control circuit, as heat reduces controller life. A cabin heater requires little more than a box with a nicrome wire, a controller circuit, and a fan. If that FET control circuit dies then it is much, much cheaper to replace the heater controller than the motor controller.

[@electrarc240]

Exactly! This is such a weird/bad idea but I was assured it is being developed

[@isprithul]

Love this type of video as an electronics hobbyist particularly interested in inverters and DC-DC converters. Just wanted to share something on the watt measurement part: I have made myself a few units of wattmeters that run a simple ESP32 S3 microcontroller. They are pretty darn accurate and precise with a 24 bit ADC and really low ppm voltage references. I use them together on the inputs and outputs of circuits I am testing, occasionally two units at the same time, that talk to each other over WiFi and show me a nice efficiency value on a webserver. I can see a lot of options for automation with this device and just a lot of use cases. Let me know if you are interested/curious about it and we can talk. I would be happy to share my schematic/PCB/3D case design.