Plug-In Power: My six days with a Plug-In Prius
Given that oil is over $130 a barrel and gas prices are above $4 a gallon, I figured it was time to test out a plug-in Prius. A123/Hymotion was kind enough to lend me one of their retrofitted cars last week, and I have to say it was an enjoyable and insightful experience. I detail my experience in my latest Clean Break column. Apologies for U.S. readers — the column discusses fuel economy as “Litres per 100 km” rather than MPG.
What I can tell you is that five of the six days I drove the car I got 100 MPG or higher fuel economy, and on some trips got over 200 MPG and even 300 MPG a couple of times. I found that driving behaviour improves with each day and you learn to use more of the electric battery than the engine, and develop techniques for doing so. The only sub-100 MPG day was when I had a 155-mile drive north of Toronto and back. I logged 55 MPG that day. Otherwise, my driving was mainly 5 or 10 mile hops around the city (I’m an urban dweller), which is perfect for a plug-in vehicle. I used a bit more than a quarter of a tank of gas and only $3.83 worth of electricity (and associated charges) during my six day trial. Most of the gas was used during my one-day trek to the country.
A couple of points. To use electric mode as much as possible you’re forced to drive less aggressively. It’s difficult at first, but after a while it becomes natural and is actually more relaxing. In fact, I realized that if everybody just drove the speed limit, learned to coast to stop signs and traffic lights, and didn’t accelerate toward every traffic light, the streets would be safer and we’d all save oodles of fuel. Using this car also made me realize the importance have having real-time feedback on fuel economy. This isn’t unique to the plug-in model, as the Prius and other hybrids have this as well. But it made me wonder: Why aren’t all cars mandated to have this feature? I mean, if we’re promoting energy displays for the home as a way to spark conservation, why not put them in the car to encourage better driving habits and fuel savings?
Wouldn’t this be a simple and inexpensive thing to do? Perhaps there are after-market products for this already. If not, I see an interesting business opportunity.
BTW: Readers of this blog obviously have high regard for all-electric and plug-in hybrid vehicles. Of the 124 people who have so far voted in my blog poll (see lower right-hand side of main page), 48 per cent said they would purchase an all-electric given the opportunity, while 32 per cent preferred to buy a plug-in hybrid. Only 8 per cent wanted a fuel cell car, while a surprising 2 per cent said they’d purchase a conventional hybrid. Flex-fuel cars also got lower votes, with just 4 per cent supporting the biofuel path. The bottom line: 80 per cent are in favour of plug power!
Tyler Hamilton is senior energy reporter and columnist for the Toronto Star, Canada's largest daily newspaper. In addition to this Clean Break blog, Tyler writes a weekly column of the same name that discusses trends, happenings and innovators in the cleantech market. This blog is a personal project started in April 2005. It is not an official blog of the newspaper. Tyler can be reached at tyler@cleanbreak.ca
June 9th, 2008 at 4:10 pm
A few design questions:
Can you reach out and switch it from gas to battery power? If you’re traveling city and later are going to be on the highway where the batteries will be charged back up, can you override its attempts to switch to gas since the batteries are getting low? Does it urge to lunge forward if in Drive even without pressing the “gas” pedal?
Can you coast, say on a downhill, and turn on the regenerative system to capture that energy and keep your speed down at the same time?
June 9th, 2008 at 4:46 pm
I have driven a Prius for the past four years and recently traded my 2004 for a 2008. Two interesting results – I am not all that light footed – but two things come out of driving with the displays that you mention. Most people that I know do try to be light on the pedal to the extent that the gas engine shuts right off for extended periods – and this would not be possible with a normal car. In cold weather, at times, the engine often runs if only to provide heat for the heater… The other thing that is interesting – when I traded my 2004 Prius – it had done 140,000 km and was still operating on the factory brakes – which the dealer claimed still had 60% remaining. I agree that the displays drive behaviour – but also think that the hybrid makes that work. I have to suspect that it would do little on a standard car…
June 10th, 2008 at 5:35 am
The increase in mpg is very tempting but until the manufactures deal with electrical and magnetic shielding, hybrid cars have a significant health question mark. There are many studies that show biological effects of electromagnetic fields, the set of studies showing high magnetic fields increase childhood leukemia are particularly relevant. The high current flows between the electric motor and battery pack result in high magnetic fields under the rear passenger seat. There is some informed discussion related to this issue on:
http://www.hybridcars.com/forums/bringing-back-hybrid-t1599.html
This problem can be resolved by manufactures but until there is sufficient public awareness they aren’t going to do it because the modifications will add to the cost of the cars.
June 10th, 2008 at 10:03 am
hey tyler – wired.com has an article on hypermilers, among other things it mentions an add-on fuel consumption gauge that gives them real time feedback. they also mention a hypermiler in ontario who sounds interesting.
http://www.wired.com/cars/energy/news/2008/06/hypermilers09
Jeff
June 10th, 2008 at 1:15 pm
There was an option to switch from gas to battery, rather than rely on the software to do it, but I never used it.
There’s no urge to lunge forward in drive. You can coast downhill and the regenerative system automatically kicks in. Not sure what you mean keep your speed down at the same time.
June 10th, 2008 at 1:24 pm
It’s certainly something that should be on the radar of the major car manufacturers. I’m not sure how much shielding would cost in high volume manufacturing, but I’m a fan of precaution the evidence either way isn’t conclusive.
June 10th, 2008 at 1:29 pm
That is a pretty strange finding – the cable from the battery is two wires in a heavy sheath. The electric field is almost zero becasue the voltage is relatively low (250 volts in a Prius – similar to what is in most household walls…) – but the magnetic field is also almost zero becasue the two currents in the two wires cancel each other. Furthermore, the cable is under a metal floor – and that provides the equivalent of a Faraday Shield that would virtually eliminate any fields inside the car. I suspect that the average person gets much more serious exposure at home.
I am an electrical engineer – with an advanced degree in power systems, with more years behind than ahead… I have worked for two electrical utilities, and done a lot of reading on fields around power lines. While I personally am a little nervous of them (I would not live under a large 500 kV line…) I have found no real evidence of problems until the fields are strong enough to impact vision – and that is an extremely strong field. If there were any real problems, it surely would have shown up on people working in electrolytic smelters (aluminum comes to mind) where currents are so large that one can stand a paper clip on its end and it will stay there… These plants are generally unionized and most unions are very vigilant on health and safety issues… I have not seen any problems there.
To avoid a hybrid car on this basis – I would suspect is totally without merit.
Can you provide some real field strentghs measured inside the car – or is this just an assumption or guess.
June 11th, 2008 at 4:42 am
Steel based Faraday cages work great on electrical fields, but have limited effect on magnetic fields. There are materials, one example is mu metal, specifically for magnetic shielding, but they are expensive.
The link I referred to contains meter readings from hybrid cars. There is also a journal article reviewing scientific papers on the effects of electrical and magnetic fields on biological systems.
There is growing body of research showing that EMFs raise the incidents of cancer, clearly the evidence is not unequivocal but ignoring it and potentially putting your children in harms way seems foolhardy.
June 11th, 2008 at 9:37 am
I go with the majority here, a plug in electric would be my choice too. in fact it has been, since i recently bought an electric scooter. ZAPINO from ZAP is a great choice IMO.
June 11th, 2008 at 10:55 am
If you are over 21 and just now figuring out that aggressive driving wastes fuel and tears up breaks and transmissions, you are an idiot.
The reason PHEV are DOA is the idiot factor. The way to save money is to brew your own coffee and not drive to restaurant while hauling heavy expensive batteries. I a really certain that the Pius that passes my going 85 when the speed limit is 65 is not getting better fuel economy than my Corolla that is $6k cheaper than a HEV and $12k cheaper than a PHEV.
Kit P
June 16th, 2008 at 9:57 pm
Oh now, don’t be so hasty. Slide that coffee away and take a deep breath.
The PHEV’s and HEV’s save a lot (LOT) on the brake pad wear, as they do on transmission wear and other component wear in general. Any idiot with experience driving one can tell you that.
It’s due to the parallel drive system that takes the heavy loads off the engine during acceleration as well as much of the brake pad wear during deceleration, due to the regenitive breaking (think of it as engine breaking, only no stress on the engine and its recovering energy). Electric motors (esp. brushless) have very, very low upkeep requirements in comparison to a typical gas engine because it has less moving parts.
So yes, your Corolla is a great car and it may very well be cheaper where you live (assuming you are in the USA) for now, but if gas prices do rise as expected, the tables will very likely turn in favor of PHEV’s and other alternative fuel vehicles including pure electric.
June 17th, 2008 at 12:27 pm
I have read several sources on hypermilling and the concept is a fantastic way to reduce your gasoline consumption. I believe the best hypermillers can reduce gasoline by about 40%. The only way, though, they can do this is by receiving feedback from a fuel consumption gauge.
So the question now is: How does the fuel consumption gauge influence Joe/Jane Driver and how much fuel can be reduced by simple driving techniques? Whatever the answer is, it will probably be positive enough to help pay less at the pump.
In a carbon taxed world, these gauges would be a great subsidy paid by tax revenues.
Darklamp
June 17th, 2008 at 12:28 pm
First, I wonder if the system that you drove (Hymotion) actually used the full capacity of the extra batteries for regenerative breaking. This is REALLY useful in hilly and mountainous terrain. I asked this of one company and they said theirs did not. I suspect it requires firmware support and may complicate the design.
Second, I have rented two Prius’s for multiday trips and found that I got 42-45MPG in spite of my relatively heavy footed driving, so i am sold that the design, not the driving patterns is significantly advantaged over ANY other car on the market….thus I ordered one for October delivery. I really would prefer to wait for the li-ion version but unless it is fairly sure for 2009 I will take my clunky NiMH version….
June 17th, 2008 at 2:07 pm
We use copper based farady cages here where I work at a hospital. Shields magnetic fields perfectly, we used to have to replace our monitors and computers regularly from the 3 Tesla magnets of some of our MRI machines. Now we don’t.
June 18th, 2008 at 10:22 pm
I’m the “hypermiler” in Ontario mentioned in that Wired article (just a coincidence that I also visit Clean Break occasionally and saw this mention).
The fuel consumption display in question is called a ScanGauge. It works in any 1996 or newer North American vehicle, and is invaluable for enabling/encouraging efficient driving technique. It’s currently the only device of its kind available, and the US company making them is apparently overwhelmed with orders.
(I have no connection to the company other than I have bought two ScanGauges).
Background: http://metrompg.com/posts/scangauge-interview.htm
August 18th, 2008 at 11:28 am
Re: “Not sure what you mean keep your speed down at the same time.”
I believe Jp Warren is referring to acceleration due to gravity as the vehicle goes down hill. Any vehicle (or rolling object) will accelerate on an incline (assuming there are no other forces acting on it.
But there are other forces that could be acting on the vehicle, and they are:
1) the ever present air resistance and rolling friction.
2) manually applied friction brakes
3) engine speed control (cruise control for example)
4) regenerative braking systems (electric and hybrid vehicles)
If the vehicle is using some form of speed control (eg. cruise control or a regenerative braking systems) the speed will remain constant. That is assuming the hill is not too steep.