Tesla Model S Charged By Diesel Generator More Efficient Than ICE (w/video)

FEB 15 2018 BY MARK KANE 42

Electric cars are extremely efficient, but this experiment proves that EVs can beat ICE even when the rules are completely changed, like when the EV is charged by a diesel generator.

Diesel Efficiency Challenge

Tesla Owners Club Western Australia, along with AEVA, tested the efficiency of the Tesla Model S P85D powered from a diesel generator and compared it to the Volvo V40 D4 2L diesel.

The result is the final blow to ICE, as the relatively efficient, small and much lighter Volvo wasn’t able to cover the same distance as the Tesla (powered from a diesel generator) on the same amount of diesel fuel.

The diesel generator provided 18 kWh of electricity using 4.460L, which was enough to drive 104.6 km (65 miles) in the Tesla. The Volvo went the same route in the same conditions, but used 4.800L of fuel!

That’s a total blast to ICE as the EV won against the smaller, lighter (1,500 kg vs 2,200 kg), less capable car, with lower performance in this worse-case scenario.

Usually, electricity is provided by the grid, which is becoming cleaner and cleaner everyday. So, under normal circumstances, the Tesla wins by even more.

Source: RenewEconomy

Categories: Tesla

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42 Comments on "Tesla Model S Charged By Diesel Generator More Efficient Than ICE (w/video)"

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The difference would be even greater with a brand new more efficient generator.

Or a car that doesn’t weigh almost 5,000 lbs

Yeah. I’d far rather see this comparison done with cars which have roughly equally powerful motors. That’s the way to approach an apples-to-apples comparison. We may never get a true exact comparison, because EVs and gasmobiles are quite different. But we can get a lot closer than this.

But thats the point. Skew the results to the Diesel Volvo and it still loses..

Don’t make the mistake of equating better efficiency with “clean”. That generator has almost nothing for pollution control. This is the same fallacy that lead to all the diesels in Europe in the first place: focussing solely on gig emissions and forgetting that is only part of the equation (and the part forgotten has real immediate effects on human health).

This is so true.
Even gas generators Stink like Diesel, they spew so much pollution. Also, they don’t tell you these generators are as noisy as a Tractor-Trailer.

It’s no pleasant experience to lose house power and have to roll out one of these generators, typically in winter to keep your heat on and your pipes from freezing.

Hopefully, we can get sufficient capacity from a Tesla Battery, and solar to trash the generator.

4.4L is about 1.2 gal. Assuming 34 kWh per gallon, it’s about 40 kWh total. 18kWh would be 45% efficient. I call BS on this extraordinarily efficient generator.

I looked at typical generators, and they are only about 10% efficient at 50% load (eg. 500W for 5 hours using 1 gallon). That means EV would waste 4 times more energy than stated.

Hmm. I think I need to write a blog post debunking this if I can get off my lazy butt.

Yep, they charged it using a huge 30kva 3 phase prime power generator. You’re going to have a hard time beating that for a quick home test.


Nope, that’s 49.2 kwh. Diesel has much more heat per 128 oz gallon than does ethanoled gasoline. (140,000 btu/128 oz gallon). 18/49.2 is around 36 1/2 % efficiency – that is HIGH but not totally unbelievable.

A 7% theoretical efficiency improvement is pretty good. Of course a Hybrid Volvo would probably get more than a 7% improvement over the standard
volvo here.

A Tesla isn’t the best for a real world test since if you ran the heater it would get horrible, plus there are those ‘vampire and parasitic losses’ you expect with Tesla over any 24 hour period.

Still, this is about as good a result as could be hoped for.

Some large stationary ICE’s get up to 54-58% efficiency even before selling/utilizing the otherwise wasted heat, but the efficiency of this portable machine is fantastic for what it is, that is true.

Well, the numbers are commensurate with the Isuzu 3 cylinder diesel as per the cut-sheet, and assuming that only 18 kwh was taken from the power cord. Now if the authors are claiming the BATTERY in the TESLA increased it charge rate by 18 kwh then that would mean 100% charging efficiency – vs the 82% charging efficiency measured by a Tesla Motors Club “S” owner from his own meter on his wallbox.

36.5 % efficiency from such a small machine is fantastic as it is. If they are claiming 44.5 % efficiency, then, Like you Curt, I don’t believe it. As I say, – run of the mill american products (Generac – which may be considered one of the ‘junkier’ American Brands) only can get 27.2 % efficiency.

Debunking what exactly? The video explains everything…

If you get 18 kWh into battery and charging is about 85% efficient, what came out of the generator was 21 kWh. At 49 kWh of diesel, that’s 43% efficient generator.

Meanwhile, grid level generators are about 33% efficient without combined cycle. What, grid operators are idiots who’d lose 10% efficiency despite having giant, expensive generators?

Follow the money. Energy just doesn’t make sense as shown in the video.

18 kWh can drive an Ioniq for 18 km.

180 km

10km/kwh!? 33% better than my Leaf at 7.5km/kwh. Are you sure?

The 700kg difference in weight also means you are comparing apples to oranges. People are smarter than you give them credit for. SHAME!

True, if the cars were the same weight, then the EV would’ve gone even farther.

Vow! Branch Elonians invented hybrid and “clean diesel” at the same time! Toyota with its priuses may finally retire! VW too. We just need to leave Bosch to supply proper emission control software for this super-efficient, clean and non-ICE diesel generator. All world problems solved at once!

For this to truly mean anything the EV must be charged buy renewables not ICE today’s gas powered cars are cleaner and more efficient than EV’s charged by ICE in an apples for apples comparison

IF this is true and can be reliably duplicated by nonpatial investigators the reason is likely that the generator can run at close to (or at) optimum speed and load whereas the car engine must operate at many non optimum speeds and loads.

To provide acceptable acceleration and hill climbing (especially to current expectations) vehicle engines must be way oversized for what would be required for highway crusing.

A series hybrid with 5-10 kwh battery buffer to provide short/medium extra power for acceleration would allow a smaller engine to run optimally driving the traction motor and putting any excess output (when crusing) into the battery and turning off when the battery reaches a nearly full charge. Charge depletion mode could be used if plug in charging is expected.

While this gives the great range and quick refueling of a gasoline/diesel car plus cabin heating from waste heat it is more complex than a BEV.

Ok, looked up a standard mobile diesel here of the common Generac Brand here in the states. 18 kwh takes 1.6 gallons of Diesel or 225,806 btu. 18 kwh is 61,434 or 27.2 percent efficiency.

This Aussie machine, if true, is just fantasic by comparison (27.2% vs. 36.5%), and that assumes 18 kwh taken at the inlet to the car. If the battery actually increased charge by 18 kwh then assuming 82% charging efficiency as delineated by a recent TMC Tesla ‘S’ owner by measuring the inlet to the car, then the efficiency becomes 44.5 %.

I would doubt even the best ausie generators are THAT much better than standard American products of the same size range.

I’m looking at Harbor Freight generators and equivalents from Home Depot. They are only about 10% efficient.

I agree, the numbers shown in this video for the generator is unrealistic. Huge piston engines could have high efficiency due to large volume for smaller surface area (relatively speaking), but there’s no way small home generators will achieve anything like what’s claimed here.

But it’s not a”small home generator”….

I agree with Reecho. This was not a small home generator. Home Depot and Harbor “Junk” Tools both just sell Chinese Junk – I usually prefer HFT if there’s a choice since at least they give you a discounted price for the Junk they sell. A small engine mechanic friend informs me that the Predator Crap HFT sells are all basically Honda Engine Designs – (china doesn’t worry about things like trade secrets), but then they take the money out. The GOOD thing about that is when the engine craps out sooner rather than later you can replace the Wrist Pin, or Connecting Rod or whatever has blown with an official HONDA quality part and it will EXACTLY FIT since its an EXACT theft of the Honda design. That has nothing to do with this article. Diesel has more heat per gallon – gasoline has nothing to do with this Test as both the VOLVO and the Generator ran on Either #1 (kerosene) or #2 fuel oil. Whatever it was, the video seems to indicate it was the SAME for both car and generator. I’m not saying there is anything wrong with the video – other commenters here smell more… Read more »
I’m sorry, but some you people really need to read a little deeper and do some of your own research. For starters, the diesel generator is much larger than the diesel engine in the Volvo. Also, the generator doesn’t all of the emissions control devices like the Volvo. Removes those from the Volvo and it would be just as efficient, if not more so, than the generator. And let’s make the comparison fair as well. It is true that without the emissions control devices, diesel exhaust is bad for a lot of things. But without them, a diesel engine is way more efficient than any gas engine or EV could ever hope to be at this point in time. For instance, it is the VW Jetta TDI, 2015 I believe, that actually holds the record for best MPG’s at 77.2 on a cross-country trip, as measured by civilians and not a company. True, it cheated the emissions, but thats not the comparison being done here. If you want further proof, watch the next locomotive go by. They have been hybrids of a sort for years, and at last check, get on avg 500 mpg’s per gallon for each ton of… Read more »

“…it is the VW Jetta TDI, 2015 I believe, that actually holds the record for best MPG’s at 77.2 on a cross-country trip, as measured by civilians and not a company.”

My B.S. detector just went off.

What you’re describing is almost certainly an extreme example of hypermiling, not the supposed efficiency of a diesel car. That is, the MPG has a lot more to do with the driver’s techniques for super-efficient driving than how efficient the car is.

Yeah, diesel-powered cars can be engineered to be more efficient than gasoline-powered cars. But only marginally so, certainly nothing compared to the 3.5x to 4x the efficiency you get when comparing a pure electric car to a pure gasmobile of similar power and weight.

And let’s not forget that the only way the makers of faux “clean diesel” cars could get their cars to appear to comply with emissions regulations, was by engineering them to fake the tests.


“If you want further proof, watch the next locomotive go by.”

A diesel–electric train includes a diesel engine connected to an electrical generator, creating electricity that powers electric traction motors.

I just started to quickly view the video and noticed that something has DEFINITELY been altered with their footage. Unless they use different units in the outback, 32 amps @ 242V is nowhere near the 23 kW that is shown on the display at the 0:46 mark. I smell something fishy.

It’s three phase. That changes the calc. I noticed on the shot of the generator display that the generator was producing 3 phase, with each leg at about 242 VAC-to-ground.If the Tesla 3-phase on-board-charger electronics uses a neutral and can accept each phase current separately and convert to DC, then the total input power would be 3 x 32 x 242 = 23,232 watts = 23 kW.

Regarding fuel use – I’m not familiar with the route, but if it had a lot of stop/go, the Volvo diesel engine effective efficiency would really plummet. And no regen to help compensate. The Model S’s generator was able sit comfortably at constant 3/4 load at its efficiency sweet-spot the entire charge. And use braking regen.

“Tesla 3-phase on-board-charger electronics uses a neutral and can accept each phase current separately and convert to DC, then the total input power would be 3 x 32 x 242 = 23,232 watts = 23 kW.” Three phase AC calculations are: A*V*1.732*pf/1000 (A= avg amps per not total) Your looking at 12-13kw depending upon the actual power factor. You also can’t power a 5kw motor load with a 5kw generator the starting inrush will lock it. Tesla most likely has a 60/40 generator to AC motor ratio and after the startup inrush passes motor running while battery charging begins. The motor is AC and the charger takes AC and charges batteries DC. When on batteries the controller inverts DC to three phase AC for the motor. Can’t be a DC motor that would be inefficient in this application. What’s cool about 3 phase motors you have an ABC clockwise rotation, to reverse the motor you switch two phases BAC, ACB or CAB this reverses the motors rotation. Could easily be done with a contactor relay. Oh and there are formulas out there to calculate the efficiency of the diesel generator provided you know the kw max and kw of the… Read more »

If you want to use that formula (Amps * Volts * Sqrt(3)), you would have to use the correct Voltage, 412 Volts.

The Voltage of this generator is 412, not 242!

The text you replied to calculated the effect for each phase *separately*, and then the *relative volt difference between the phases* was used, instead of absolute voltage.

Re-calculate using your formula, and the correct 412 Volts, and you end up with the same result….

You and HVAC MAN are saying the same thing – you guys are just looking at the same generator from a different angle.

That said, since the voltmeter in the car is in the 242 volt range, it is likely that the Tesla doesn’t realize or ‘care’ there is 412 volts there the same as the ‘480 volt’ Tesla Superchargers cannot stand much more than 277 volts nominal (like 285). If you got out your voltmeter and started measuring leg to leg, you’d see the high voltage. But Tesla doesn’t directly use it anywhere – except maybe for the prop fans in the corral – whether those are single or three phase probably depends on what was on sale this week.

Were the two cars driven in the same manner? The Telsa has a consumption of 172 Wh/km (3.6 miles/kWh), which is lower than the real world consumption of a Tesla S.

So electric beats diesel flat out and the important factor is the Tesla weighing 50% more than Volvo and is also much faster. I am sure the Volvo would have driven slowly.

Sorry Diesel- UK is going to increase taxes on Diesel vehicles and its sales in Europe is on the downtrend.

I don’t think generators are as efficient as power plants.

A modern power plant can generate 33 KWh with 1 gallon of gasoline and with that electricity, Tesla Model S can go 100 miles and that’s why the term 100 MPGe.

And with Diesel, the power plant can generate 38 – 40 KWh since Diesel has 15% extra energy.

So with 40 KWh, Model S can go 120 miles. Now how many miles will this Volvo go on 1 gallon of diesel.

Reserve power plans may be the same diesel generators.

It depends really. There is wast variety of power plants and generators. $999 Honda from HomeDepot is not most efficient and nobody cares about it. Electric grid typically doesn’t run on gasoline 😉 Real life nat. gas or coal plants are not much greater than ICE by efficiency if you add cycling up and down and losses in grid.


Theoretical combined cycle turbine efficiency is few percents higher, but it is equivalent of measuring mpg of hypermiling Prius instead of using EPA cycle.

You’re nuts.

CCGT plants have best in class real world efficiency above 60% net. That’s real world, net efficiency taking all loss into account including the generation losses (so called at the fence efficiency).

That’s accurate. There are serious generating machines, and then there are the toys they sell at HFT and Home Depot.

ALthough, as I mentioned before, Stationary large ICE’s are up to 58% efficient even before the waste heat is sold/utilized. But again, these are serious machines, not toys.

Have s look at http://electricinsights.co.uk/
This is where EVs are now making serious leaps forward regards being green. Much to most people’s surprise most of our power doesn’t come from coal, and only about half from gas.
Have a look and let me know what you think.


So… you’re saying that the diesel potential energy to mechanical kinetic energy to electricity to electrical potential energy in a battery to mechanical energy was more efficient that the one from diesel to mechanical in the Volvo?
I guess that Diesel Generator manufacturer need to be prized or someone can apply for a Noble prize…