cross-posted from: https://lemmy.world/post/22892955
The Prius Prime is a dual fuel vehicle, able to run 100% on Electric, or 100% on gasoline, or a computerized blend in-between. This presents me a great opportunity to be able to do a direct comparison with the same car of an EV engine vs an ICE engine.
Toyota computer claims 3.2mi-per-kwhr.
Kill-a-watt (https://en.wikipedia.org/wiki/Kill_A_Watt) claims 2.2mi-per-kwhr.
Additional 1.5% losses should be assumed in the wires if you wish. (120V drops down to 118V during charging, meaning 2V of the energy was lost due to the resistance of my home’s wires).
Level 1 charger at home (known to be less efficient).
Toyota computer claims 53miles-per-gallon (American Gallon).
I have not independently verified the gallon usage of my car.
295 miles driven total, sometimes EV, sometimes Gasoline, sometimes both.
30F to 40F (-1C to 4.5C) in my area this past week.
Winter-blend fuel.
12.5miles per $electricity-dollar (17.1c / kw-hr home charging costs)
17.1 miles per $gasoline-dollar ($3.10 per gallon last fillup).
If anyone has questions about my tests. The main takeaway is that L1 charging is so low in efficiency that gasoline in my area is cheaper than electricity. Obviously the price of gasoline and electricity varies significantly area-to-area, so feel free to use my numbers to calculate / simulate the costs in your area.
There is also substantial losses of efficiency due to cold weather, that is well acknowledged by the EV community. The Prius Prime (and most other EVs) will turn on a heater to keep the battery conditioned in the winter, spending precious electricity on battery-conditioning rather than miles. Gasoline engines do not have this problem and remain as efficient in the winter.
I originally wrote this post for /c/cars, but I feel like EVs come up often enough here on /c/technology that maybe you all would be interested in my tests as well.
Nice info! A few notes:
Volts are not energy. Volts are a component of electrical energy. The drop in voltage is because of the additional load on the circuit that the charger represents. Energy losses come out as heat. If something gets hot while it’s doing its job and its job is not to heat things it means that it’s got a loss of energy somewhere. I’d bet that the charger warms up in use, and the loss is likely greater than the 1.75% loss that you were thinking you had with the voltage sag.
L1 charging is less efficient for a few reasons, but the biggest increase you get in efficiency from the L2+ charges is time. Triple the charge rate gets you full in an afternoon rather than overnight. But then you can parlay that into cost savings by timing your charge to off-peak times and charge up on cheaper electricity, if it is available in your area.
Electric cars do have an easily measurable range drop in cold weather for the reasons you outlined. Gas cars really shine in cold weather because not only do they not perform measurable worse in terms of range when the thermometer drips, but they also make their own heat, ALL THE TIME. In electric cars you have to use battery power to heat both the battery and the cabin, which is yet another drain on range. But, that gas combustion heat is loss in the summer when you’re not using it. Like the waste from your charger, but this time it also comes with emissions.
Not to mention, for a naturally aspirated IC engine, you actually make more power in cold weather due to it being more thermodynamically efficient with a colder intake. (This is the reason why an intercooler increases the power output of a tuner car.)
Oh yes.
But a wire’s resistance is purely ohmic (or damn near a pure resistance, very little inductance or capacitance to discuss).
So seeing a voltage sag of 120V (original) to 118V across the 11 Amps my charger pulls means we can calculate the resistance to be 0.2Ohms.
The rest of the 118V to the charger and the car is the usable power. After all, the current is constant (11Amps).
Power = Voltage * Current.
With 2V * 11Amps being wire waste (22W in the wires in my home), and roughly 1298W delivered to the actual charger
Additional losses are clearly evident (winter, battery heater, air conditioner etc. etc.) later. But the 22W of wire-heat waste / 1320W of power drawn from my power meter (where my electric bill is calculated) is the 1.5ish% loss of this element.
So the 1.5W is literally the loss in my homes wires, before accounting for the charger itself heating up.
It sounds like you know all this but just want to clarify and double check.
I get £0.09 /kwh for overnight charging. I spend about a fifth as much on electricity for my car each month than I spent on petrol on my previous car.
Why does your car calculate your petrol efficiency but not your electrical efficiency? Sometimes hybrid cars are sold as being more fuel efficient, so report the fuel efficiency of the gas by including the electricity-fueled miles in when calculator the gas efficiency. (Toyota haven’t historically been terribly enthusiastic about electricity.)
My overall miles per gallon was 85mpg including electricity.
The 53mpg is within other tests (ex: consumer reports), and is within expectations.
Why does your car calculate your petrol efficiency but not your electrical efficiency?
On the contrary. I don’t trust Toyotas EV efficiency figure of 3.2mi/kwh because I’m measuring 2.2mi/kwh from the wall.
Are YOU measuring the electrical output from the wall correctly? The cars battery has a figure but it’s after the efficiency losses in the cable, heater and other such figures. My calculation includes all the losses except voltage sag in wires (1.5% estimate)
I’m calculating money I was charged by my electricity company actually during charging hours versus miles I actually drove. (The amount of electricity my house uses at that time of night is small and ignorable.) I’m trusting the milometer, but I think that’s reasonable. It isn’t claiming it’s further to work than my previous car did!
In any case, it was almost five times as expensive on petrol as it is on electricity in my usage, and even if you adjusted the figures slightly it wouldn’t make a difference. And the pure electric car is so much more fun to drive, with so much more oomph than any other car I ever drove. I love it.
I still think it’s weird that you’re not calculating your own gas efficiency. Toyota have a vested interest in you thinking they’re doing a great job of that. I don’t know why you’re trusting their figures for gas but you’re supremely skeptical about their figures for electricity. Why would they be so inconsistently honest with you, and why are you so inconsistently skeptical?
I still think it’s weird that you’re not calculating your own gas efficiency. Toyota have a vested interest in you thinking they’re doing a great job of that. I don’t know why you’re trusting their figures for gas but you’re supremely skeptical about their figures for electricity. Why would they be so inconsistently honest with you, and why are you so inconsistently skeptical?
You fucking serious mate?
Toyota figures are confirmed by consumer reports, car and driver, motor trend. Everyone is getting 50mpg even in the cold with the Prius.
The reason I’m not doing it personally is simple: it’s a 50mpg fucking vehicle. I need to drive 200miles to use 4 fucking gallons. That’s a long time to do a silly internet debate.
I’m going to do that eventually. But for fucks sake man, before criticizing my tests how about you think what the fuck I need to do to make effective tests here.
I’ll get a 200mi test done eventually. But not because you told me to do it. I always was planning on doing it but fuck man. You are a piece of shit for pushing this on me.
How about this. You go rent your own fucking car, spend 4 hours driving it and testing it and come back here so that I can shit on your results and tell you how you did it wrongly just because it doesn’t match my biases. Sound fair?
That escalated quickly!
As an outside observer, I was reading these posts calmly and under the impression it was a discussion between the both of you, then i read this comment, and the first line shocked me.
Where did all that rage come from?
Seriously, it was like maybe in the past an electic car slept with your wife.
All they said was they thought you might be biased, and you exploded. And what followed was you screaming at this person to take back what they said about you being biased whilst you insult and swear at them like they had walked into your house on christmas day and pissed on the kids.
Calm down, mate. It’s just a car.
All they said was they thought you might be biased, and you exploded
Yup. Because it’s not honest. It’s clear the discussion is worthless at that point.
If they can’t even hold the pretense of an honest discussion, none of the words after will matter. So might as well get this over with and make it clear that I intend to end the discussion unless they back down from the bias accusations.
Protip: if the other guy in a discussion thinks you are biased, it’s a waste of time to engage in honest discussion. It doesn’t matter if they are a MAGA conspiracy theorist or a fanboy or anything. The discussion goes nowhere and I’m confident it’s a waste of time.
And it’s a waste of time, I need to make it clear in no uncertain terms that I’m ending the discussion ASAP.
If you see my point about bias then I’m happy with the words I’ve selected. It’s made it clear what I’m mad about. Second tip: if someone is insulting you and making you mad, it’s okay to be mad on the internet and show your emotions. We don’t have to be robots.
Now tell me, am I actually wrong in any of this?
Putting my edit at the top.
You completely changed your response to me so now it looks like i am responding to something you didnt say. I should have quoted i guess.
Anyway, gonna leave the comment i made as some of it is still relevant.
It’s not baseless though is it?
They saw your results and asked for confirmation around the way your car calculates mpg m/kwh. Stating that many manufacturers state the mpg of a hybrid based on the combined milage gained from fuel and battery.
Based on this, he is requesting information around how you calculated your numbers. and asking why you use the company stated range for fuel (which might be fuel and battery but also might not) but use your own battery range measurements.
This in and of itself is a fairly innocent question, and if youbare carrying out tests, then you should be open to criticism or query around your method.
In order to get reliable outputs, you need to make reliable inputs.
None of this is to say you are wrong. You may absolutely have planned these tests perfectly, and the other person may be wrong. But if they are, then prove it. They have made a good point. If you have accounted for the issue they are bringing up, then you should have an answer to dispute them.
Aaaannnyway
This is all irrelevant. My point was only that they asked you a question (again, making a claim that was not “baseless”), and you blew up.
This is how it looks from the outside.
Now if you address their claim then this whole matter is put to bed. But by all means, carry on insulting them.
I suppose its none of my business.
Putting my edit at the top.
Yes. Apologies for that. I’m thinking plenty of things on this subject.
But rest assured I’m mad and I’m proud to display my anger on this discussion. I can see you are an honest and reasonable outsider so it’s different than the other guy.
I made it clear that to do the test they’re asking for is four fucking hours of test at a minimum.
And then they come back and call me fucking biased. Okay you fucking asshole. You run the test. Don’t complain to me.
The fucking gasoline test is going to take a long time, it’s going to force me off of EV mode for literally days and I’ve actually got busy things this week (wedding, work, etc. etc). I have no time to do a substantial gasoline test anytime soon.
You may absolutely have planned these tests perfectly, and the other person may be wrong. But if they are, then prove it
The other asshole hasn’t tested jack shit and is just bullshitting from his keyboard. I owe him, and you, nothing.
I’ve offered my test data on the internet. I don’t have anything else to offer.
As I said before and I’ll say it again: if he wants to spend hours answering this question, and if I get a free stab to call him biased in the new topic he makes, then yes, I’ll change my tune. But we all know he’s just trolling me.
What, you think I have the test data you want or something? That these fuel test results magic themselves out of the air? Someone actually has to take the time and do this test.
Now if you address their claim then this whole matter is put to bed. But by all means, carry on insulting them
Lulz. I owe you and him nothing. I did the tests in the top of the page and I stand by my tests. I don’t owe additional tests (let alone fucking hours of work) to anyone else.
Do you think the temperature stays still? The temperature in my area is back up to 50F today, which if I started the gasoline test it would have negated the results. This shit changes per fuel type and and per temperature.
Now tell me, am I actually wrong in any of this?
Most of it.
if the other guy in a discussion thinks you are biased, it’s a waste of time to engage in honest discussion.
This is you admitting that you are being dishonest?
make it clear that I intend to end the discussion unless they back down from the bias accusations.
You’ve been extending the argument for days. Doesn’t seem to be effective to me.
And it’s a waste of time, I need to make it clear in no uncertain terms that I’m ending the discussion ASAP
Not yet you haven’t.
If you see my point about bias then I’m happy with the words I’ve selected. It’s made it clear what I’m mad about. Second tip: if someone is insulting you and making you mad, it’s okay to be mad on the internet and show your emotions. We don’t have to be robots.
Personally, I think your anger makes you seem much more biased, not less at all.
If it helps, I have an older Prius and I get about 50mpg using the odometer on the car and the gas meter at the pump. It’s not consistent every fill up because it uses a bladder instead of a rank, so this us averaged over multiple fillups. Sometimes I calculate 64, sometimes 45, and sometimes 50 on the nose. My driving patterns are very predictable, going to and from work 2x/week and some shopping.
I’ve had the car for 10 years now and I’ve consistently gotten about 50, sometimes closer to 45 if winter is particularly nasty.
And this is a regular Prius, not a plugin. The numbers are about what Toyota advertises, if not a little better. I only calculate it because I’m curious, and at this point it’s a complete waste of time.
Note that winter-blend fuel has 10% or less energy in it. Summer-blend fuel has the most energy. And then E15 has less energy, depending on the current market of Ethanol vs Gasoline, you’ll get a little bit more or less energy out per gallon of gasoline.
The variance is expected. No two gallons of gasoline is exactly the same, there’s many blends in the USA and the blends change season-to-season, location-to-location, and even as the laws shift (0% Ethanol decades ago, 10% typically today, and a smooth blend up and down from there depending on what the gas stations decide).
I’m sorry for making you cross, but if we can trust Toyota’s figures, why not just quote Toyota’s figures? I still don’t get why your skepticism is so one-sided.
I didn’t mean to give you a bad day, but my petrol costs were soooo much higher than my electricity costs, by a factor of about five, and about 50%-60% of that saving is because overnight electricity is so cheap. Even without that, it’d still be cheaper.
But the main thing about my pure electric car is just the joy of driving. It’s so responsive, fast and smooooth. I love it.
I’m sorry for making you cross
Lulz, No you’re not. Every fucking EV asshole talks the same as you do. You’re probably congratulating yourself for triggering me. Don’t worry, I’m not a dumbass. So I’m making sure I call you out on it.
But seriously dude, it takes a lot of time to do these tests and just blatantly fucking accusing me of bias? And you’re not even taking it back? Fuck you man.
Or do you at least take back your insinuations of bias? I did this test, I’m publishing this here on Lemmy. I’m proud of what I accomplished and will defend it. And your accusations of bias are not going unnoticed. You take it back before I take by my curse words or “triggered” perspective. I get you’re a fanboy but you’re directly insulting my work here.
Best part? I drove 100% electric last week, aside from the gasoline tests. I’m on the pro-EV side and pro-electrification side. But that’s not enough for you fucking purists. I’m doing these tests so that others know how electrification works and have something closer to the honest truth. I’ve already bought the EV, the batteries and am working to have an electrified future.
It’s just that you took Toyotas numbers at face value for gas but you’re extremely skeptical about their electric figures, and out of the regular car manufacturers they stuck out to me as one of the most reluctant to go electric, so it seems odd to me that you test one but seem to take the marketing figures for the other as gospel. I think you should at least do a fair test, and genuinely I’m sorry at how cross that makes you, but I don’t think you were at all even handed and I don’t see the need to pretend that you were just because you’re shouting and swearing at me a lot.
Anyway, I’m not sure me doing an additional four hours of testing will make any difference to my monthly figures. I drive way more than that every week.
My own numbers were based on actual amounts charged by my energy company and actual amounts charged at the pump vs miles actually driven, and I didn’t see any need to complicate that. I’m paying about a fifth as much for electricity as I did for petrol, but prices for electricity are low overnight here and petrol is taxed more than where you are, I guess.
You call me a purist, but I only got a pure electric car because I was pursuaded to test drive one and I fell in love with how responsive and fast it was to drive compared with all the other cars I ever drove. I don’t think the prius in particular or hybrids in general have a great reputation for being fun to drive, which is probably why I’m enjoying my car so much more than you seem to be. Certainly I wouldn’t want to go back to driving a sluggish, noisy, thirsty, expensive-to-run gas-powered car that I have to keep taking to a petrol station to fill up again, it’s just so much nicer and less hassle driving pure electric. It’s easily my favourite car ever.
genuinely I’m sorry at how cross that makes you
which is probably why I’m enjoying my car so much more than you seem to be.
Yup. As I said before and I’ll say again. Fuck you. You are a fucking child and I’m happy to have called you out on this.
Grow the fuck up. Don’t pretend to issue apologies when you clearly have no intention on following through. You can’t even get through your apology post before deciding to attack again.
I’ve dealt with your kind before and I’ll continue to call you out on it.
But don’t worry. You didn’t fail any expectations of mine. I never expected you to pass this simple test.
Come back when you actually have evidence to share and more than just insults.
Over in Sweden it would be hard to replicate these results. Gasoline is ~18SEK/l ($7.5 per gallon).
My electricity production cost changes by the hour, so I can steer my cost by charging when it’s costs are low. Taxes and transfer costs give me a minimum of about $0.07/kWh. A smart charger that picks when to charge based on price can probably average you a cost of $0.10/kWh over the year.
That’s crazy. Gas is less than half that in the US (<$3/gal in my area, just over $3/gal national average). If my gas was $7.50/gal, I’d definitely be driving electric.
The EU has strict climate goals to push away from fossil fuels. The current goal is to ban the sale of new combustion engine cars by 2035.
The fuel here contains a bit more renewables, which also costs more o produce. Still, more than half of the cost of fuel is tax. They had a nice tax break for buying a new electric car for a while, but that window has passed.
Where I live gas is like 4.50, but electricity is also run by a for-profit company that the state doesn’t regulate.
I have a question about these dual fuel cars, gas has a shelf life and can mess up your engine if you let it sit for too long. Would this become an issue if you only make short, electric drives in the car?
The manual of mine specifically points this out and says that if you go three months without burning any fuel the engine will start being used until about a third of a tank is consumed.
Yes but there is an easy solution. Just fill up with 2 gallons, rather than 10 gallons.
Now you have the 100mi backup gasoline (why you bought a PHEV, right?), but still do EV every day. Every few months hit the HV button and burn off that fuel and fill up another 2 gallons.
That being said: Prius Prime dual mode has 0-60 time of 6.6 seconds. When both engines are on your acceleration is amazing, on both low end 0-30 EV) and high end (ICE engine covers 30-70mph).
So you want to be in auto mode (aka: use both engines mode) anyway for optimal driving experience.
And now that I know that gasoline is cheaper in the winter anyway, maybe I push that ‘use both engine’ button more…
If you ever need the 500mi gas tank for a long trip, just spend 5 minutes at a gas station. It’s not like our gas tanks are locked behind 20+ minute chargers or whatever.
most hybrids run the engine for a few minutes a month anyway, as a precaution. keeps it lubricated and sloshes the fuel around to prevent it from layering.
also i don’t know how common this is but my car pressurises its tank to prevent offgassing, which apparently keeps the fuel good longer.
Gas does… but we’re talking a years before it’s going to damage anything. It loses its octane rating and can eventually start to gum up, but we’re talking years and years at that point.
Thanks for this. Are you planning to take more measurements during a warm season? It would be interesting to see how close the electric system comes to petrol in more favourable conditions/climates.
2.87mi/kwhr is the final number for 50F test.
That’s +38% range. Or conversely, a 28% drop during freezing conditions. Or 72% efficiency near freezing compared to 50F.
Measured from Kill a Watt and therefore still a L1 charger that may have other inefficiencies.
Huge differences between 50F and 30F. Very curious indeed
Today was 50F (10C) and I’m estimating closer to 3mi/kw-hr.
Or in other words, warmer weather is close to +25% more range and efficiency compared to last week’s cold weather test.
Note that this number is very preliminary (ie: reliant upon Toyota’s battery measurements) and I’m currently recharging my car with the Kill-a-watt to verify my initial estimates. I’ve also got a work meeting tomorrow morning, but I’ll try to write down the results of today’s warmer weather test and report back to you.
Alternatively, if I forget to write down the Kill-a-watt results tomorrow morning, I’ll just repeat the test again on Wednesday or something. It should be warm weather all this week.
Of course! I plan to keep this car for around a decade, so there’s plenty of opportunity next year to experiment again.
Between the heater during charge + the heater during driving (!!!), we are getting hit twice by the cold weather efficiency demons.
Very surprising. I have the same car and drive mostly on electricity from a trickle charger. I hate gasoline so I probably wouldn’t switch even if it was more expensive, especially since I only drive about once a week, but still. My garage is extra cold too due to my heat pump water heater, so that could make things worse.
- 12.5miles per $electricity-dollar (17.1c / kw-hr home charging costs)
- 17.1 miles per $gasoline-dollar ($3.10 per gallon last fillup).
UK figures:
- Right now my electricity price is 6p/kWh, but the wind is rather high today (Storm Darragh). Still there are tariffs that guarantee 7.5p (9¢) overnight for car charging. That gives 24.3 miles per $electricity.
- Petrol is ~£1.40 a litre here ($5.30 per US gallon). So, 9.8 miles per $gasoline.
How is that rate possible? My UK (Octopus) electricity rate is 23.44p/kWh. The energy price cap is 24.5p/kWh. There cannot be anyone out there offering a price of 6p/kWh - I suspect you are looking at your gas price (where 6p/kWh would be about right)
No. Electric. My price changes every 30 minutes.
I wrote that message this morning when the price was low. Now at 5pm the price is nearer 40p. Obviously you don’t charge a car at peak prices.
Over the last 4 weeks I’ve averaged 18p/kWh. That’s mainly by making sure I do things like charge the car when it’s cheap.
My rate is very variable, but the figure I used is the off-peak rate on a rate designed for EV owners that gives cheap overnight electricity.
My gas price is 5.9p/kWh which also changes, but day by day. Today is average.
I did read about wind energy making night time costs very low for some areas of the UK. Thanks for the graph, it helps me understand it.
In my state in the USA, I have a choice between one price at all times (17c, all taxes and surcharges included) or a on-peak/off-peak pricing structure of 28c on-peak and 12c off-peak.
Not as extreme as your every 30 minutes of change but if I squint I can kinda-sorta see my price differences kinda lining up with yours.
My lows aren’t as low and the highs aren’t as high. They are also multiple hours long of on peak vs off peak.
Interesting. The internet suggests 22p/kwhr is the UK average ($0.27/kwhr in US dollar)
I do have a time of use program that I could take advantage of to drop my night time / off peak prices. But my on-peak prices go up so much that even with the EV I’m not saving any money.
I’m only going to drop from like 17c to 12c if I switch to the EV time of use program, or a change of like $1.70/night worth of charging to $1.20/night (10kwhr per typical day of travel)
Do UK citizens pay generation + transmission + taxes like we do in the USA?
8p/kwhr (10c/kwhr) is very close to the time of use / night time charge generation costs of my area. However, there are still local tax, surcharges, and transmission I have to pay for that would take that up to 17c when it’s all accounted for.
Do UK citizens pay generation + transmission + taxes like we do in the USA?
We pay a standing charge per day. Mine is 40p. So every day my costs are 40p + my per kWh costs. There’s also 5% tax on domestic electricity, but the prices I quoted include this.
Thank you for converting it. Great to see how it would compare around the world
