Test Equipment Anonymous (TEA) group therapy thread

[Specmaster]

 

Right, I'm going to ask a question about electric cars, has anyone here either got one, or has driven one? I have no experience of them personally, but I have been told that they are extremely difficult to control the speed of when you are driving them. A friend of a friend claimed that they had been told by someone who has a Tesla that it was hard to control the speed of it, claiming that felt like the motor was either full power or no power with almost nothing in between. My question is, is this sort of correct? Logic tells me that it can't be, otherwise they wouldn't be allowed to be on the road?

I can't make any comment on Teslas but I recently bought a Mercedes EQC400 electric car and I am still trying to adapt to the different driving style required.

The speed control does seem more twitchy than an ICE but it is certainly not a case of full power or no power. The apparent twitchiness may be due to the throttle response of the electric motor being more rapid than an ICE so it is possible to overshoot your desired power setting by being a little bit too heavy on the accelerator pedal. More delicate control of the pedal pressure is required.

Also, the regenerative braking from the electric motor on releasing the accelerator pedal is more aggressive than what you get from the engine braking of an ICE.

Another aspect that is quite difficult is keeping within the speed limit. Since there is no audible feedback from the motor on acceleration it is very easy to creep up over the speed limit without realising it.

Now that makes more sense, thanks for your input, I think you hit the nail with the response being quicker and therefore easier to overshoot the power setting desired 

[Specmaster]

In Sweden, as in Norway, we're doing our electricity from water, wind, sun and boiling water by neutron bowling.  An EV charged from our ...from Megawatt Valley (the likes of Drax, Ferrybridge and Eggborough)...

You're a bit behind the times. Drax now runs almost exclusively on biomass. As I write only 1% of UK demand is coming from coal. Basically we hardly burn any coal now, and only then at times of very high demand during winter or darkness. Ferrybridge and Eggborough are both decommissioned.

Do you happen to know if we still have power stations fuelled by recycled waste products? Wasn't there once a station at Edmonton that used to incinerate material sorted out at the local waste disposal unit, ie, the stuff that could not be recycled. I also seem to remember another station in Norfolk I think just off the A11 where they used to burn things like chicken manure? 

[mnementh]

Right, I'm going to ask a question about electric cars, has anyone here either got one, or has driven one? I have no experience of them personally, but I have been told that they are extremely difficult to control the speed of when you are driving them. A friend of a friend claimed that they had been told by someone who has a Tesla that it was hard to control the speed of it, claiming that felt like the motor was either full power or no power with almost nothing in between. My question is, is this sort of correct? Logic tells me that it can't be, otherwise they wouldn't be allowed to be on the road?

I can't make any comment on Teslas but I recently bought a Mercedes EQC400 electric car and I am still trying to adapt to the different driving style required.

The speed control does seem more twitchy than an ICE but it is certainly not a case of full power or no power. The apparent twitchiness may be due to the throttle response of the electric motor being more rapid than an ICE so it is possible to overshoot your desired power setting by being a little bit too heavy on the accelerator pedal. More delicate control of the pedal pressure is required.

Also, the regenerative braking from the electric motor on releasing the accelerator pedal is more aggressive than what you get from the engine braking of an ICE.

Another aspect that is quite difficult is keeping within the speed limit. Since there is no audible feedback from the motor on acceleration it is very easy to creep up over the speed limit without realising it.

Now that makes more sense, thanks for your input, I think you hit the nail with the response being quicker and therefore easier to overshoot the power setting desired 

Yeah.... EVs as we have them now, acceleration and amount of applied power is not directly linear, but a matter of driver input vs a huge number of conditions only the computer knows at any moment, and output is wholly controlled by the computer.

This means that sometimes it feels much more responsive, sometimes much less, and we linear-thinking meatsacks don't exactly know what the result will be when we half-mash the pedal vs full-on stomping it.

It's sortof like having a flight-controller on a car, I suppose; the FC is always trying to keep it level to an extent, so your inputs may seem ignored sometimes and exaggerated at others.

mnem
 

[mnementh]

Every car not produced will have a positive effect on our natural resources.

As will home office by cutting the amount of commutes.

But we can't have that. We have to have centralized cubicle hives so the Great Pyramid socioeconomic structure is maintained. Ifni forbid someone who can do two people's work actually get two paychecks by working for two employers from home; or worse yet, be able to take an extra piddle break without the galactic overlords knowing it.

mnem
 

[Specmaster]

Every car not produced will have a positive effect on our natural resources.

As will home office by cutting the amount of commutes.

But we can't have that. We have to have centralized cubicle hives so the Great Pyramid socioeconomic structure is maintained. Ifni forbid someone who can do two people's work actually get two paychecks by working for two employers from home, or worse yet, be able to take an extra piddle break without the galactic overlords knowing it.

mnem
 

Thats a fair point and may account why there is so much resistance to working from home, because the overlords feel that you are untrustworthy to leave you to get on and do the job unsupervised 

[mnementh]

Well, it's more than just that... it really is to keep you thinking that somehow the current pyramid social structure is normal, rather than the abomination it objectively is.

mnem
 

[Cerebus]

The speed control does seem more twitchy than an ICE but it is certainly not a case of full power or no power. The apparent twitchiness may be due to the throttle response of the electric motor being more rapid than an ICE so it is possible to overshoot your desired power setting by being a little bit too heavy on the accelerator pedal. More delicate control of the pedal pressure is required.

I suspect what some people are attributing as 'twitchiness' is really about having some torque available to them to them for the first time in their driving careers. The torque curve of most EVs is much flatter than ICEs, resulting in ICE drivers who'd probably be used to a 1200, 1600 or 2000 cc petrol engine buying a vehicle that has a roughly similar ultimate power output but with much higher torque available at typical road speeds.

Take the 2013 Chevy Spark (the first EV I could find torque and power curves for). It's got about 1700 Nm of torque at the axle, or 524 Nm 'at the crankshaft' from 3mph to ~30mph, with a 0-60 time of 7.8 seconds.



The same chassis with the fastest petrol engine version available had 112 Nm at the crankshaft @ 4400rpm, and made 0-62 in 11.3s. And of course with the petrol engine, the torque at low revs is proportionally lower, unlike the EV where it's almost constant until around 40 mph (where they start to do field weakening on the motor).

So a relatively humble EV is going to have better acceleration (and hence throttle response) than a reasonably quick sports car, and is going to stomp over a petrol equivalent of the same class. If you're not used to that level of throttle response, then yeah, it's going to seem twitchy, just the same as if you jumped out of a Corsa and into a Porsche 911.

[beanflying]

Electrical power distribution losses in the USA are about 5%.
https://www.eia.gov/tools/faqs/faq.php?id=105&t=3

Complete efficiency of Bulk grid power with a Fossil fueled base is circa 20% if it is lucky. If you charge your EV off the grid ergo the efficiency is not good.

[mnementh]

The speed control does seem more twitchy than an ICE but it is certainly not a case of full power or no power. The apparent twitchiness may be due to the throttle response of the electric motor being more rapid than an ICE so it is possible to overshoot your desired power setting by being a little bit too heavy on the accelerator pedal. More delicate control of the pedal pressure is required.

I suspect what some people are attributing as 'twitchiness' is really about having some torque available to them to them for the first time in their driving careers. The torque curve of most EVs is much flatter than ICEs, resulting in ICE drivers who'd probably be used to a 1200, 1600 or 2000 cc petrol engine buying a vehicle that has a roughly similar ultimate power output but with much higher torque available at typical road speeds.

Take the 2013 Chevy Spark (the first EV I could find torque and power curves for). It's got about 1700 Nm of torque at the axle, or 524 Nm 'at the crankshaft' from 3mph to ~30mph, with a 0-60 time of 7.8 seconds.

The same chassis with the fastest petrol engine version available had 112 Nm at the crankshaft @ 4400rpm, and made 0-62 in 11.3s. And of course with the petrol engine, the torque at low revs is proportionally lower, unlike the EV where it's almost constant until around 40 mph (where they start to do field weakening on the motor).

So a relatively humble EV is going to have better acceleration (and hence throttle response) than a reasonably quick sports car, and is going to stomp over a petrol equivalent of the same class. If you're not used to that level of throttle response, then yeah, it's going to seem twitchy, just the same as if you jumped out of a Corsa and into a Porsche 911.

That's part of it, but not all of it... I've built/ridden a number of homebrew e-scooters and cycles from component parts with simple ESCs. They of course have similarly flat torque curves and high power/weight ratio, but throttle response is still much more linear and predictable to meatsack brains. It's not just twitchy; it's not the same response every time you mat the pedal or feather it.

There really is a noticeable variance in how having the computer in the middle of the feedback loop makes it feel; just like some petrol vehicles with Sport/Economy modes.

Mostly, I think it's a matter of getting used to the idea of not having direct, instantaneous right-foot control, vs driving it for a week or two then going back to petrol powered vehicles, tho.

mnem
 

[Cerebus]

In Sweden, as in Norway, we're doing our electricity from water, wind, sun and boiling water by neutron bowling.  An EV charged from our ...from Megawatt Valley (the likes of Drax, Ferrybridge and Eggborough)...

You're a bit behind the times. Drax now runs almost exclusively on biomass. As I write only 1% of UK demand is coming from coal. Basically we hardly burn any coal now, and only then at times of very high demand during winter or darkness. Ferrybridge and Eggborough are both decommissioned.

Do you happen to know if we still have power stations fuelled by recycled waste products? Wasn't there once a station at Edmonton that used to incinerate material sorted out at the local waste disposal unit, ie, the stuff that could not be recycled. I also seem to remember another station in Norfolk I think just off the A11 where they used to burn things like chicken manure?

There's loads of biogas from compostable waste now and it's increasing all the time, and there are several (individually relatively small, a few MW or 10s of MW each) waste burning plants. Perhaps 50-60 plants for those two lumped together at the moment. A lot of the biowaste plants are at the sites of waste production and energy consumption - there's at least one big brewery that burns their brewing waste for heat and electricity generation. Unfortunately all the official statistics are lumped together as "bioenergy" which includes biomass like wood pellets, so it's difficult to pull figures out.

[nixiefreqq]

nope.  this guy figured it out.  (maybe)

https://spectrum.ieee.org/energy/environment/a-retired-jpl-engineers-journey-from-space-probes-to-carbonneutral-farming

[Cerebus]

I've built/ridden a number of homebrew e-scooters and cycles from component parts with simple ESCs. They of course have similarly flat torque curves and high power/weight ratio,

In your dreams buddy!  What are we talking, about 8 bhp/tonne?

I couldn't find a large enough dragon on a small enough scooter, so this will have to do:

[mnementh]

LOLOL... that actually is pretty much what my current toy will look like, too.    But I was talking aboot a much younger/slimmer me, and ni-cd powered scoots with golf-cart motors.

mnem
tzzzzt!!!

[mnementh]

nope.  this guy figured it out.  (maybe)

https://spectrum.ieee.org/energy/environment/a-retired-jpl-engineers-journey-from-space-probes-to-carbonneutral-farming

IIRC, lots of NO_x from burning ammonia, plus it is just plain hazardous. We lived a few miles away from one of the biggest ammonia chemical reactors/storage tanks in the US where I lived in Victoria, and only a few more miles away from another huge one in Houston. We saw numerous programs warning us in both locations that if that tank or reactor had ruptured in any serious way, our entire neighborhood would have been dead before we knew aboot the explosion.

One thing people don't consider because it's so hard to measure is the global temperature rise from burning sh...tuff to make energy. Trading one kind of emissions for another is just a crutch; we don't know what those alternate emissions will do over the long haul either. Until we shift to a zero-emissions power cycle (not net-zero or carbon-offset or any of the other dozens of weasel-word excuses for not cutting the combustible fuel umbilical), we are fucking doomed.

Bottom line is that no matter how we do it, we are not going to survive long enuf to develop interstellar flight unless we stop burning stuff to make energy.

And the global warming clock just keeps ticking down; it is not going to hear the excuses or pay attention to all the bullshit. Once the balance is tipped far enough, we're fooked and no amount of whining "I'm so sorry" is going to matter; Mother Earth will shrug her shoulders and in another million years or 20 some other form of life will get their chance to do it right or fook it up.

But humanity will not be there in any recognizable form to witness it.

mnem
"Honey, where is my weeoux...?"

[srb1954]

I suspect what some people are attributing as 'twitchiness' is really about having some torque available to them to them for the first time in their driving careers. The torque curve of most EVs is much flatter than ICEs, resulting in ICE drivers who'd probably be used to a 1200, 1600 or 2000 cc petrol engine buying a vehicle that has a roughly similar ultimate power output but with much higher torque available at typical road speeds.

That may be true for some EV buyers but in my case I wasn't upgrading from some low-performance vehicle - I actually downgraded slightly in moving from a high performance AMG sports SUV to the EV.

Even so I still think the EV has a "twitchier" throttle response compared to the petrol-engined equivalent.

[mansaxel]

In Sweden, as in Norway, we're doing our electricity from water, wind, sun and boiling water by neutron bowling.  An EV charged from our ...from Megawatt Valley (the likes of Drax, Ferrybridge and Eggborough)...

You're a bit behind the times. Drax now runs almost exclusively on biomass. As I write only 1% of UK demand is coming from coal. Basically we hardly burn any coal now, and only then at times of very high demand during winter or darkness. Ferrybridge and Eggborough are both decommissioned.

I actually already knew this, but I think from reading about them (and watching videos on boating on the Aire) that those three are some of the more iconic ones in the Valley, so that's why I chose them. More of a figure-of-speech than a power generation report :-D

Add-on: A very fitting comparison as to why it is sensible to run an EV, even from coal-sourced electricity, is to compare the pollution, local foremost but also global, from thousands of small coal fires in semi-detached housing to the centralised combustion in one of those big ones.

[cyclin_al]

Any good bearing supply house will carry highly polished and hardened bearing grade steel balls.

Yep, true .... but ....
Here in the great white north, a gross (144) of those ball bearings will cost you in the vicinity of $9 at a good bike shop.  At a not-so-good modern bike shop, all they will have is one bike brand of sealed bearing units.  At a bearing shop, expect to pay about $0.75 per ball; they must be genuine imperial based on that price...

[Saskia]

@mansaxel I tend to disagree. I still think CNG is one of the best ways to drive your car. CNG is just burning cow farts instead of letting it go into the atmosphere. The only problem is: we need to capture those farts to recycle them.

Now, if we composted all those politicians and used them to propel our cars they would be doing something useful for a change.

[Specmaster]

Thinking back to the topic of EV cars and that it maybe the torque that makes speed control more difficult when compared against smaller petrol (gas) powered cars because EV cars do have huge amounts of torque almost instantly available whereas petrol engines develop their torque typically around 4,000RPM. I remember when I first switched from petrol-engined cars to diesel that diesel, that it struck me as being difficult in traffic to control the speed effectively. Why do I say this, because I remembered that if I parked close to a kerb, and it was necessary to mount the kerb from a standing start, the petrol engine need to be given a bit of right boot to climb it, otherwise it is likely to stall, whereas, depending on the engine size, a diesel would tend to climb up the kerb at idle speed due to that increase in low down grunt. These days after many years of having diesel powered cars, I have become accustomed to it and adjusted my right foot behaviour accordingly. 

[Cerebus]

Thats the whole point they are purely estimates, and they are so often wrong. For instance Car A might only do 10,000 miles it is life before it is either written off in a accident or EOL and Car B could do 250,000 miles, who knows, the manner in which they are driven will also as you say, will also impact on the cars carbon footprint, to many variables to give reasonable accurate figures, unlike the carbon footprint it takes to produce the car in the first instance and get it to the showrooms in theory is a far better bet to measure the footprint of.

What happens once the vehicle is sold is anyone's guess, and it needs to take into account not just if the driver has a heavy right foot, but also the terrain, hilly, flat, tarmac, mud tracks, sand, snow etc all will greatly affect the results.

So I take it you think that a hundred years of private vehicle ownership isn't enough experience for us to have accumulated sufficient data to accurately predict how people use privately owned vehicles? Obviously there is a huge body of statistics in the hands of governments and motor vehicle manufacturers that says otherwise. Or perhaps you think that 100 years of engineering experience building the same isn't a sufficient basis for predicting the likely lifetimes and failure modes of their components over that lifetime? If that's true then I think we'd better throw the whole profession of engineering in the bin.

Nope, we're got quite enough data and experience to be able, as engineers and scientists, to come to some reasonable conclusions as to the environmental impact of substituting EVs for ICE vehicles. And people have, and have published that data and those conclusions. On that basis, I don't think there's any element of the "jury still being out".  The only reason that there might appear to be, to some people, is that there are a whole shitload of vested interests involved who'd like to muddy the waters. The tactic of falsely claiming a need for "further study" is such an old delaying tactic that it was handed out in advice on sabotage in WWII.

(11) General Interference with Organisations and Production
(a) Organizations and Conferences
(1) Insist on doing everything through "channels." Never permit short-cuts to be taken in order to expedite decisions.
(2) Make "speeches." Talk as frequently as possible and at great length. Illustrate your "points" by long anecdotes and accounts of per­ sonal experiences. Never hesitate to make a few appropriate "patriotic" comments.
(3) When possible, refer all matters to committees, for "further study and considera­tion." Attempt to make the committees as large as possible — never less than five.
(4) Bring up irrelevant issues as frequently as possible.
(5) Haggle over precise wordings of com­ munications, minutes, resolutions.
(6) Refer back to matters decided upon at the last meeting and attempt to re-open the question of the advisability of that decision.
(7) Advocate "caution." Be "reasonable" and urge your fellow-conferees to be "reason­ able" and avoid haste which might result in embarrassments or difficulties later on.
(8 ) Be worried about the propriety of any decision — raise the question of whether such action as is contemplated lies within the juris­ diction of the group or whether it might conflict with the policy of some higher echelon

(Some of us may also recognise elements of the above as "good business practice" as promulgated by a certain class of PHBs.  )

As engineers and scientists we ought to be immune to this kind of propaganda, especially in this day and age where getting your hands on peer reviewed science and engineering publications packed with hard facts is a few clicks away on the Internet. Instead, as has been evidenced many times by the too-ing and fro-ing about EVs across the whole of this forum, we as a body seem to be just as gullible as readers of the Daily Mail or the National Enquirer.

[Specmaster]

And back to TEA, this message just arrived, so I have my spray bottle of IPA already to disinfect the meter first before inspecting and powering it up, more on it later. 

[McBryce]

Regarding the safety of EV's and their batteries, there is no real safety advantage between Cylindrical and Prismatic packs. Cylindrical have some minor cooling advantages, but getting the same power density as prismatic packs is difficult. Mechanical strength is important, but the electronic monitoring will react well before any mechanical component has failed. The batteries are monitored (voltage, current, Charge state, State of Health and temperature) on the cell pack level, so even if a single cell shorted, the system will react in microseconds and like any ICE vehicle, the entire power source is also cut as soon as any crash is detected.

As for the driving experience, as mentioned above, it's the torque curve that people notice at first. People are used to an engine needing time to react, especially if they drove a diesel up to then. The motor definitely isn't an ON/OFF situation, it's just like any variable motor control.

I won't comment on the environmental or infrastructure aspect, that's politics not engineering and will be different for every country.

McBryce.

* This information/opinion doesn't come from a report, I've worked in EV and EV Baterry development for almost 20 years, including work on the Prius.

[Cerebus]

Any good bearing supply house will carry highly polished and hardened bearing grade steel balls.

Yep, true .... but ....
Here in the great white north, a gross (144) of those ball bearings will cost you in the vicinity of $9 at a good bike shop.  At a not-so-good modern bike shop, all they will have is one bike brand of sealed bearing units.  At a bearing shop, expect to pay about $0.75 per ball; they must be genuine imperial based on that price...

A gross? I thought the gross went out with Gentleman's Outfitters pricing everything in Guineas. I'll remember that next time I hear some Canahouvian waxing lyrical about how superior they are to their southern cousins because they've managed to get to grips with the metric system instead of measuring things in bushels per league or furlongs per fortnight. 

[tautech]

And I didn't take pics  when at the Navy Cal lab today of all the gear they had...universal calibrators, reference signal sources, voltage sources, bench meters by the dozen, counters and all top class plus other TEA items too numerous to list.
Talk about a kid in a candy shop.....all of it very yummy. 
Wiped the dribble off my chin all the way home. 

Now they have a couple more Siglents, yes more to add to the potpourri of instruments they have already. 

[Specmaster]

So I take it you think that a hundred years of private vehicle ownership isn't enough experience for us to have accumulated sufficient data to accurately predict how people use privately owned vehicles? Obviously there is a huge body of statistics in the hands of governments and motor vehicle manufacturers that says otherwise. Or perhaps you think that 100 years of engineering experience building the same isn't a sufficient basis for predicting the likely lifetimes and failure modes of their components over that lifetime? If that's true then I think we'd better throw the whole profession of engineering in the bin.

Nope, we're got quite enough data and experience to be able, as engineers and scientists, to come to some reasonable conclusions as to the environmental impact of substituting EVs for ICE vehicles. And people have, and have published that data and those conclusions. On that basis, I don't think there's any element of the "jury still being out".  The only reason that there might appear to be, to some people, is that there are a whole shitload of vested interests involved who'd like to muddy the waters. The tactic of falsely claiming a need for "further study" is such an old delaying tactic that it was handed out in advice on sabotage in WWII.

(11) General Interference with Organisations and Production
(a) Organizations and Conferences
(1) Insist on doing everything through "channels." Never permit short-cuts to be taken in order to expedite decisions.
(2) Make "speeches." Talk as frequently as possible and at great length. Illustrate your "points" by long anecdotes and accounts of per­ sonal experiences. Never hesitate to make a few appropriate "patriotic" comments.
(3) When possible, refer all matters to committees, for "further study and considera­tion." Attempt to make the committees as large as possible — never less than five.
(4) Bring up irrelevant issues as frequently as possible.
(5) Haggle over precise wordings of com­ munications, minutes, resolutions.
(6) Refer back to matters decided upon at the last meeting and attempt to re-open the question of the advisability of that decision.
(7) Advocate "caution." Be "reasonable" and urge your fellow-conferees to be "reason­ able" and avoid haste which might result in embarrassments or difficulties later on.
(8 ) Be worried about the propriety of any decision — raise the question of whether such action as is contemplated lies within the juris­ diction of the group or whether it might conflict with the policy of some higher echelon

(Some of us may also recognise elements of the above as "good business practice" as promulgated by a certain class of PHBs.  )

As engineers and scientists we ought to be immune to this kind of propaganda, especially in this day and age where getting your hands on peer reviewed science and engineering publications packed with hard facts is a few clicks away on the Internet. Instead, as has been evidenced many times by the too-ing and fro-ing about EVs across the whole of this forum, we as a body seem to be just as gullible as readers of the Daily Mail or the National Enquirer.

Nope, we have to remember that engines of today are hugely more efficient than those that came and went before them and that trend is ongoing. Not only do we get considerably more power extracted from a litre of petrol now, but we also get a massive drop in the emissions of those same engines, plus new cars now have start/stop technology and some cars actually shut down upto half of their cylinders so there are more savings that weren't possible before. Bio-fuel can be grown and processed locally thus removing the high-cost energy wise of building drilling rigs and other such gear to extract oil from the earth, transport it to a refinery etc, so it is perfectly possible that ICE cars will become superclean and EV may not be needed just yet, who really knows what  tomorrow will bring?