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October 29, 2008
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Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Ann Arbor, Mich. — As General Motors ramps up for the 2011 Volt and Toyota readies the long-awaited, factory-built plug-in Prius, customers wait-and wait. And wait. Even when these cars hit the market, some 24 months from now, demand will be very high. It could take many more years for production plug-in hybrids to reach mainstream garages in America.
But why wait? Prius owners can turn their cars into plug-ins today with a $10,395 L5 plug-in conversion module from Hymotion. Plug-ins allow owners to charge their batteries with a household electrical outlet overnight, then drive on electrical or mostly electrical power until the battery is depleted. When there's no more battery capacity left, the gas engine takes over. The range of pure electric travel depends on battery capacity and driving style, but for reference, Chevy expects the upcoming Volt to go 40 miles on electric power. Hymotion claims its kit will deliver between 30 and 40 miles of electric-only range. Current production hybrids like the Toyota Prius go less than a mile on electric-only operation.
To find out whether the Hymotion claims are valid, we slid behind the wheel of a fully charged plug-in Prius and drove it for two days. Do plug-ins live up to the hype? Let's find out. —Larry Webster
The kit is mostly not a do-it-yourself affair. A buyer will have to take his Prius to one of six authorized installation centers spread across the country (you can locate the shops here). Installation is included in the purchase price.
In addition to the battery pack, the module includes a three-prong plug that's mounted in the rear bumper, a dash switch that turns the extra battery on and off, and a reprogramming of the Prius's computer so the readout displays the charge state of both the A123 and the standard Prius battery packs.
As with any electric car, the battery pack is the key to the system. The A123 unit is unique, the company says, because it can be completely depleted without sacrificing longevity. Current batteries, like the stock one in the Prius, use only a small portion of the available energy capacity. That helps to extend the life of these expensive packs. GM engineers say the Volt will use only half of its 16-kwh hour rating-it will be charged to 80 percent of its capacity and drained to about 30 percent. But A123 engineers say they've tested single-cell versions of their batteries and after 7000 cycles, the battery still retains over 80 percent of its full capacity. If we figure one charge per day, the A123 battery could potentially last for almost 20 years. Trials for multicell packs such as the one in the L5 module are ongoing, but engineers expect similar robustness.
While there are many lithium-ion batteries on the market, the internal chemistry of the batteries varies widely. It's this "pixie dust," as one engineer put it, that separates the batteries. Cost is of course a major issue. Current estimates put the latest li-ion batteries at about $1000 per kilowatt-hour. Even if that price tag is reduced by half, these plug-in hybrids will carry a hefty premium over their gas-powered siblings. The widespread acceptance of plug-ins will ultimately come down to oil prices.
The dash switch that engages the A123 battery pack has a light that glows when the system is engaged and battery has a charge. As soon as the supplemental battery is depleted, the light turns off so we would know exactly when it was drained.
We pressed the main power button on the Prius and immediately the gas engine kicked on. While we had enough electrical power on board to move the car easily, the engine still runs every now and then to warm up. It was a chilly, 46-degree morning and if we had wanted to heat the cabin, the engine would have continued running. But it was our job to see how we far we could travel on electric power so we shut off the climate control.
Our in-town loop consisted mostly of stop-and-go driving with peak speeds less than 50 mph. We quickly realized that a subtle right foot is required to keep the gas engine from coming to life and we practiced our best hypermiling techniques. Anything more than a quarter-throttle and/or uphill grades caused the engine to kick on.
It was possible to pull away on pure electric power and accelerate up to roughly 35 mph. Above that speed, the engine would cycle on and off and we knew from a drive the previous day that the engine would sometimes turn off once the car was cruising-even at 65 mph.
Our best indication of the engine's operation was the Prius's energy-flow screen, which shows the power flowing from the engine and batteries to the front wheels and conversely displays reverse flow when coasting or braking. One thing we noticed was that the Hymotion computer reprogramming wasn't perfect. The battery icon, which is supposed to show the state of charge of both batteries, flickered between green and blue, making it almost impossible to tell how much charge was left.
Functionally, however, the car felt like a standard Prius-the difference was that it was in electric-only mode far more often. Since the Prius's electric motor is only good for 67 hp, the gas engine had to assist from time to time, but careful driving kept that to a minimum.
After 24 miles the light went off, indicating that the A123 battery was depleted. We charged up the battery again that night. The next day we drove a different loop that had less traffic lights- this time, the Prius went 25 miles. Once the A123 battery is drained, the Prius behaves like the standard-issue Toyota product.
We also measured the fuel economy during our short drive-it averaged 54 mpg. That figure is not accurate, however, because the amount of fuel we added was about a gallon and filling the gas tank to the exact same point both times proved impossible. A little extra gas on the refill makes a dramatic swing in the mpg figures. The Prius's onboard computer registered 70 mpg, which is likely closer to the real number. It's also important to note that "miles per gallon" is a misleading number here, because we didn't increase efficiency, we just used electrical energy in place of chemical energy.
On the other hand, saving money isn't the whole point. The idea is to find another way to power our cars that uses less oil. And for a lot of folks, that's all that really matters.
Even though our electric range wasn't over 30 miles, other users, who are likely more skilled at stretching every electron, have achieved better than 30 miles on a charge. The Hymotion L5 appears to be a solid conversion. Other than the flickering battery display, the car felt like it could have come straight from the Toyota factory.
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Ann Arbor, Mich. — As General Motors ramps up for the 2011 Volt and Toyota readies the long-awaited, factory-built plug-in Prius, customers wait-and wait. And wait. Even when these cars hit the market, some 24 months from now, demand will be very high. It could take many more years for production plug-in hybrids to reach mainstream garages in America.
But why wait? Prius owners can turn their cars into plug-ins today with a $10,395 L5 plug-in conversion module from Hymotion. Plug-ins allow owners to charge their batteries with a household electrical outlet overnight, then drive on electrical or mostly electrical power until the battery is depleted. When there's no more battery capacity left, the gas engine takes over. The range of pure electric travel depends on battery capacity and driving style, but for reference, Chevy expects the upcoming Volt to go 40 miles on electric power. Hymotion claims its kit will deliver between 30 and 40 miles of electric-only range. Current production hybrids like the Toyota Prius go less than a mile on electric-only operation.
To find out whether the Hymotion claims are valid, we slid behind the wheel of a fully charged plug-in Prius and drove it for two days. Do plug-ins live up to the hype? Let's find out. —Larry Webster
The Specs
The centerpiece of the Hymotion module is a 5-kilowatt-hour lithium-ion battery pack manufactured by Boston-based A123Systems. The battery pack and its associated electronics supplement, but do not replace, the standard Prius nickel-metal-hydride battery pack and fits in the spare-tire well of the Prius. So while installation of the kit means there's no place for the spare tire, the Prius's generous cargo area is preserved.The kit is mostly not a do-it-yourself affair. A buyer will have to take his Prius to one of six authorized installation centers spread across the country (you can locate the shops here). Installation is included in the purchase price.
In addition to the battery pack, the module includes a three-prong plug that's mounted in the rear bumper, a dash switch that turns the extra battery on and off, and a reprogramming of the Prius's computer so the readout displays the charge state of both the A123 and the standard Prius battery packs.
As with any electric car, the battery pack is the key to the system. The A123 unit is unique, the company says, because it can be completely depleted without sacrificing longevity. Current batteries, like the stock one in the Prius, use only a small portion of the available energy capacity. That helps to extend the life of these expensive packs. GM engineers say the Volt will use only half of its 16-kwh hour rating-it will be charged to 80 percent of its capacity and drained to about 30 percent. But A123 engineers say they've tested single-cell versions of their batteries and after 7000 cycles, the battery still retains over 80 percent of its full capacity. If we figure one charge per day, the A123 battery could potentially last for almost 20 years. Trials for multicell packs such as the one in the L5 module are ongoing, but engineers expect similar robustness.
While there are many lithium-ion batteries on the market, the internal chemistry of the batteries varies widely. It's this "pixie dust," as one engineer put it, that separates the batteries. Cost is of course a major issue. Current estimates put the latest li-ion batteries at about $1000 per kilowatt-hour. Even if that price tag is reduced by half, these plug-in hybrids will carry a hefty premium over their gas-powered siblings. The widespread acceptance of plug-ins will ultimately come down to oil prices.
The Drive
We used a standard extension cord to connect our garage-wall outlet to the bumper port of the Prius. The car's brake lights illuminated to inform us that the juice was indeed flowing and then dimmed to indicate that the batteries were charging. After roughly six hours, the brake lights turned off, which meant the pack was fully charged.The dash switch that engages the A123 battery pack has a light that glows when the system is engaged and battery has a charge. As soon as the supplemental battery is depleted, the light turns off so we would know exactly when it was drained.
We pressed the main power button on the Prius and immediately the gas engine kicked on. While we had enough electrical power on board to move the car easily, the engine still runs every now and then to warm up. It was a chilly, 46-degree morning and if we had wanted to heat the cabin, the engine would have continued running. But it was our job to see how we far we could travel on electric power so we shut off the climate control.
Our in-town loop consisted mostly of stop-and-go driving with peak speeds less than 50 mph. We quickly realized that a subtle right foot is required to keep the gas engine from coming to life and we practiced our best hypermiling techniques. Anything more than a quarter-throttle and/or uphill grades caused the engine to kick on.
It was possible to pull away on pure electric power and accelerate up to roughly 35 mph. Above that speed, the engine would cycle on and off and we knew from a drive the previous day that the engine would sometimes turn off once the car was cruising-even at 65 mph.
Our best indication of the engine's operation was the Prius's energy-flow screen, which shows the power flowing from the engine and batteries to the front wheels and conversely displays reverse flow when coasting or braking. One thing we noticed was that the Hymotion computer reprogramming wasn't perfect. The battery icon, which is supposed to show the state of charge of both batteries, flickered between green and blue, making it almost impossible to tell how much charge was left.
Functionally, however, the car felt like a standard Prius-the difference was that it was in electric-only mode far more often. Since the Prius's electric motor is only good for 67 hp, the gas engine had to assist from time to time, but careful driving kept that to a minimum.
After 24 miles the light went off, indicating that the A123 battery was depleted. We charged up the battery again that night. The next day we drove a different loop that had less traffic lights- this time, the Prius went 25 miles. Once the A123 battery is drained, the Prius behaves like the standard-issue Toyota product.
We also measured the fuel economy during our short drive-it averaged 54 mpg. That figure is not accurate, however, because the amount of fuel we added was about a gallon and filling the gas tank to the exact same point both times proved impossible. A little extra gas on the refill makes a dramatic swing in the mpg figures. The Prius's onboard computer registered 70 mpg, which is likely closer to the real number. It's also important to note that "miles per gallon" is a misleading number here, because we didn't increase efficiency, we just used electrical energy in place of chemical energy.
The Bottom Line
Financially, the Hymotion system makes little sense. Sure, it cost less than 50 cents to charge the battery each night, but the A123's 25-mile range only saved about a half-gallon of gas. At current gas prices it would take over a decade to save enough money to pay for the kit.On the other hand, saving money isn't the whole point. The idea is to find another way to power our cars that uses less oil. And for a lot of folks, that's all that really matters.
Even though our electric range wasn't over 30 miles, other users, who are likely more skilled at stretching every electron, have achieved better than 30 miles on a charge. The Hymotion L5 appears to be a solid conversion. Other than the flickering battery display, the car felt like it could have come straight from the Toyota factory.
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20. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Since I can't afford a Tesla roadster, and I do have a Prius, it made sense to me to try the A123 upgrade. Since I have a 48-mile roundtrip commute (and no way to charge at work), I only average about 75 mpg. But I think that it's important to vote with my dollars and tell the car companies that there really is a market for more eco-friendly vehicles. It's true that any fuel used to produce the electricity ought to be counted in the total fuel efficiency, but it's different for everyone. In my case, I actually DO have solar panels to generate the electricity, but even so, most people, charging at night, are using power that would normally be wasted, and so the fuel (whether it's coal, natural gas, or whatever), would still be used. I'd rather have a full EV, but for now, the plug-in hybrid is the best I can manage.
19. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
If we could even copy the Prius correctly we could make a lot of progress. The plug in crowd continues to ignore the 38% efficient engine of the production Prius (Argonne data available if anyone cares.) Then they fail to notice that the Prius method where there is a direct mechanical link from the engine to the wheels which avoids the generator loss, battery loss, and motor loss. The mechanical link has some loss though even the electric motor has to be linked to the wheels. Even worse, sticking batteries in a Prius as the 100+mpg crowd does actually degrades the Prius engine to 32%. ( Argonne data exists on this point also.) The biggest disaster of all is that the plug-in crowd would have us believe that the source fuel for electricity can be ignored in their mpg quotes. How embarrassing is this? Of course there is the dream that solar or wind is going to get done in massive quantities. And then we are subjected to the economic trick where the evaluation of cost feasibility is based on subsidized costs, and usually the cost of money is ignored. Think about how our electric bills will look when we are all getting subsidies from ourselves. And then the federal budget will stagger under the load, even more than it is staggering now.
18. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
#17....you still drive a SCOOTER. This is a car that can carry someone in comfort. I get great gas mileage on my $700 bicycle too but thats also irrelevant
17. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I drive a $2000 Ego-vehicle all-electric scooter and get the same range as the $30,000 Prius with a $10,395 Hymotion plug-in conversion. I get the same range and commute every day. For the money the "green" doofusses are spending, I could get 20 scooters. Of course now that gas is back to $2 a gallon, the payback period for electric vehicles is approximating the expected time before the sun goes super-nova. Happy motoring!
16. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
To address #15s questions: "How does the plug-in compare to the non plug-in Prius?" For the moment ignore production efficiency. A gallon of gasoline contains 36.6kWh of energy. At an EPA highway 45 mpg, that works out to 813 Wh/mile. At 4-5mi/kWh, the Prius (or Volt) on electric uses ~200-250 Wh/mi. The average speed of the EPA test is 48mph. At 48 mph the mechanical energy required to sustain the Prius' speed is ~186Wh/mile. While the thermodynamic efficiency of the Prius' ICE may be reduced by its lower duty cycle of use in a PHEV, the fact that its only providing ~10-20% of the cars motive power during that cycle makes that small change fairly irrelevant as much less gas will be used overall. Once the battery is depleted on longer trips the ICE will return to its original duty cycle and efficiency. Electric generation and distribution can be as low as ~30% as you say. It can also be as high as 100% using decentralized renewables. Even if you double or triple the electrical operation number to account for the poor efficiency of these older plants and add an appropriate overhead for gasoline production, electric still comes out better than burning gasoline. It does illustrate though that while a move towards pluggins is a good start, it must be met by equal pressure to move the electric industry towards more efficient and cleaner sources for major longterm gains to be made. That may not be as hard to do as many would think though. With the incentives available 1/1/09, you could install a solar array with capacity to drive a PHEV Prius or Volt 40 miles a day (~2.3kW DC) for 20+ years for ~$3,300. That works out to 1.14c/mile. Even if you financed it to avoid the upfront cost and doubled the overall cost, 2.3c/mile is still way better than the 6.5c/mile you pay for gas in a Prius at $3 a gallon, or even the 4.3c/mile at $2 a gallon. Having your gas price locked for 20+ years at the equivalent of $1.05 per gallon, and magically contain virtually no GHGs or smog emissions and be 100% domestic (on your own roof) sounds pretty good to me.
15. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
#9 appropriately bases comparisons on btu of heat and lbs CO2, though key problems of that post are: (1) Charging is at night to get the low electric rates and this night time electricity is generated the power generating capacity that costs the least to operate. This is conventional coal power which operates at 32% efficiency on average in the USA. (On the national stage, there is not much coal gasification going on, whatever that might be.) (2)Certainly the average car is a horrible waste of energy. The interesting question is, "How does the plug-in compare to the non plug-in Prius?" I wonder if the Hymotion people make it clear that the Argonne tests of the "Engine efficiency on UDDS Cycle" showed average engine efficiency of 32.6% for the Hymotion modification compared with 38.2% for the Production Prius. Cars such as the Aptera and Miastrada (my project) show ways to make a much more important change to the automobile world. Both utilize electric equipment. However, these projects show the kind of results that are needed. Plugging in a car is not a bad thing to do, but it does not accomplish very much. These efforts should not cause a sense of complacency.
14. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I live in a big city, and a LOT of people drive less than ten miles to work; the majority, however, drive around 22 miles to work - theres a well known suburb to the west of the city, and most of the middle class persons drive on a freeway from that suburb to the city. If those people could charge their car at work, and they had one of these upgraded Prius', then they would use very, very little gas - gas is always needed for acceleration; electricity can accelerate like theres no tomorrow, but it would drain even one of these big-ass battery packs very quickly. But if a hundred thousand people or so in a city could get to work and back while using less gas than could fill a can of soda (330ml), then pollution goes down, oil use goes down, noise would go down slightly, all while achieving the same goal - to get to work on time.
13. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Actually, it IS all about saving money, since man-made global warming is simply the latest in a string of "sky is falling" HOAXS put on people over the last 40 years (in the 70's, it was the "impending ice age" (source, national geographic). Make it pay and people will be all over it.
12. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I run a Hymotion pack in my prius - I would expect an OEM product to be more integrated in terms of meeting the peak efficiency requirements of the engine to the battery but that being said - I still maintain fuel economies in the upper 80's and lower 90's and I've trimmed out the aerodynamics to keep 100+ at 65 mph - so I guess it's about enabling growth and stirring up the pot more than improving the tiny fleet of vehicles that have taken on the kit. I believe the future includes both fuel and electricity as part of a balanced drive and I will happily pay a price to help sponsor that change.
11. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Well, electric drive is fundamentally efficient. Get used to it. Power plant turbines are up to three times as efficient as your typical car engine, in typical car usage. So, there is plenty of margin for transmission line, battery and motor losses, and still come out twice as efficient, and 6 times cheaper. Now, the difference in Prius engine efficiency is due to the Prius engine being run at lower power. But this does not mean that more overall energy used by the Hymotion Prius. Its very possible to degrade engine efficiency to 10%, if the engine only pushes the car 100 yards, on a 20 mile trip, and still have that car use less energy.
10. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Website: www.peakoilgarage.com
I have had a Hymotion system installed for about 3 weeks now. My average MPG was also about 85 mpg initially. After about 1 week of experience, my average is now above 99.9 mpg. In pure EV mode (under 35 mph) it will go about 22 to 25 miles. At highway speeds of 55 mph, the Hymotion system will last about 40 to 45 miles and provide about 150 mph ave fuel consumption. Then it converts to standard Prius mode. Experience counts when using the Hymotion system. It takes a few days to learn how best to use the extra electric power.
9. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Sorry, but there is really no question about the vastly improved energy efficiency possible with electric vehicles. The only shell games in town are those being played by the oil companies. A recent study by the DOE estimated the well to wheels BTU efficiency of conventional and hybrid gas electric vehicles, comparing them to fuel cell vehicles fed by coal gasification. Their numbers were 5,900 btu/mile for an average 2005 gasoline car, and 4,200 btu/mile for a 2005 gas/electric hybrid. The fuel cell vehicle was estimated (in an ideal lab environment) at 5,100 btu/mile in 2005, and they are hoping to hit 3,200 btu/mile by 2030. Unfortunately they don't include full electrics in the same paper, but we can take a pretty good wag at a comparable value. A modern combined cycle natural gas or coal electric plant runs at about 7,000 btu/kWh. US average transmission and distribution loses are around 7.2%, so lets add 25% overall for transmission and charging inefficiencies. That gets us to 8750 btu/kWh. Electric car efficiencies range from about 3-5 miles/kWh. The Volt mentioned above is coming in at ~40 miles/8kWh or ~5 kWh/mi, the Prius has been found to be right around there as well or even a little better. So 8750 btu/kWh / 5 miles/kWh = 1750 btu/mile. So even on natural gas and coal, an electric (PHEV or BEV) is more than 3 times as efficient as an average car, almost 2.5 times more efficient than a hybrid, and almost twice as efficient as they hope a fuel cell will be in 20+ years. From a CO2 perspective, a modern coal plant emits ~1.8 lbs/kWh, natural gas about 1.0 lbs/kWh. With 19.6 lbs released per gallon of gas, coal is the equivalent of 54mpg, natural gas 98 mpg. When you look at solar, wind, hydro, nuclear etc the picture gets even better for electrics in terms of both btu and CO2 efficiency.
8. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
It all depends on your priorities. If your focus is on reducing our dependence on foreign oil, or oil in general, MPG is still a very valid measurement. It accurately shows the reduction in gasoline consumption. The problem with any sort of alternative accounting, is that it is highly dependent on assumptions which make it very susceptible to bias. Where do you assume the electricity comes from? How do you determine equivalence? BTUs? Lbs of CO2? Lbs of NOx? Lbs of SOx? In my mind the beauty of PHEVs and eventually BEVs is that you have a choice about where to get the electricity from. A car that drives on gas is 100% dependent on oil. A car that drives on electricity can be powered by coal, nuclear, natural gas, hydro, solar, wind, methane, biofuels etc. That flexibility has a lot of inherent advantages with regards to pollution, cost and energy independence. Thats not to trivialize the importance of keeping pressure on the electric industry to expand their use of renewable, but at least the option is there unlike the current petroleum dominated situation.
7. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Here in Massachusetts the cost for a KWH is 20 cents. So, it's going to cost you around a *buck a night to charge your A123 pack. 25 mile range? So it's 4 cents a mile? *(Not accounting for charging losses). Of course if you don't live in MA, charging up is going to cost you a LOT less.
6. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I am an owner of a Hymotion L5 unit. I am getting much better mileage than your test indicated. I am finding as it is getting colder the efficiency of the unit is going down. I am currently averaging 88 MPG on my second tank of gas since the middle of September. Calculating individual trips using the Multi Function Display on my 1st tank of gas ranged between 111 and 212 mpg. It is all in the way you drive the vehicle. Terrain, speed and distance traveled are also factors. You are right about payback. I calculated my payback as 29 years (since I already owned the Prius). IT IS NOT ABOUT PAYBACK. It is about doing what I can now to mitigate my personal contribution to global warming. The electricity I use to charge my Prius is 100% renewable (from solar panels on my roof). The car is home from work midday so there is enough sunlight to charge the pack.
5. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Website: http://www.miastrada.com
The writer of number 2 comment is nominated to the honest mpg club. Writer of number 1 is nominated to the electric car shell game club.
4. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I looked carefully at the Argonne presentation labelled "SAE 2007 Congress" which shows side by side graphical data on engine efficiency, with the Hymotion Prius on the left side and the Production Prius on the right. The average engine efficiency for the Hymotion version is recorded at 32.8% and the Production Prius is 38.2%. I read this to say that the Hymotion arrangement significantly degrades the otherwise amazingly good performance of the production Prius. The widely misrepresented efficiency of electric operation creates such irrational enthusiasm that this fact seems to get overlooked. But far worse is the deception that electric operation is fundamentally efficient. Of course it is if run from hydro power, but the marginal response to each plugged in electric car will be added burning of coal for many years to come.
3. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Website: www.calcars.org
Great report. Of course, as they say, "your mileage may vary." For any trip where the car drives mostly on the highway when the engine doesn't have time to warm up, results will be worse. For a range of conditions, see the results posted by Google.org's RechargeIT program at http://www.google.org/recharge/experiment/ using the previous generation of Hymotion conversions -- 93.5 MPG average, 115.1 MPG for city trips. On the miles per gallon, the 100+MPG claim makes even more sense when you add the footnote "plus a penny a mile for electricity" (figuring about 125 Watt-hours/mile and 8 cents/kWh). -- Felix Kramer, Founder, The California Cars Initiative (CalCars.org)
2. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Isn't it about time we start using mileage estimates for plug-in hybrids that don't cheat? Calculating the amount of gas used isn't the whole thing. We should also include the electricity used. After all, if I push my car down the road while it is idling, it doesn't mean my car magically gets 300 mpg. Energy costs money regardless of its form. A plug-in hybrid has vast efficiency advantages over a conventional car, so why cheat? Report a figure that gives the total equivalent MPG, not just the amount of gas used. In that way, consumers can make an informed comparison.
1. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Website: www.calcars.org
Great report. Of course, as they say, "your mileage may vary." For any trip where the car drives mostly on the highway when the engine doesn't have time to warm up, results will be worse. For a range of conditions, see the results posted by Google.org's RechargeIT program at http://www.google.org/recharge/experiment/ using the previous generation of Hymotion conversions -- 93.5 MPG average, 115.1 MPG for city trips. On the miles per gallon, the 100+MPG claim makes even more sense when you add the footnote "plus a penny a mile for electricity" (figuring about 125 Watt-hours/mile and 8 cents/kWh). -- Felix Kramer, Founder, The California Cars Initiative (CalCars.org)
Since I can't afford a Tesla roadster, and I do have a Prius, it made sense to me to try the A123 upgrade. Since I have a 48-mile roundtrip commute (and no way to charge at work), I only average about 75 mpg. But I think that it's important to vote with my dollars and tell the car companies that there really is a market for more eco-friendly vehicles. It's true that any fuel used to produce the electricity ought to be counted in the total fuel efficiency, but it's different for everyone. In my case, I actually DO have solar panels to generate the electricity, but even so, most people, charging at night, are using power that would normally be wasted, and so the fuel (whether it's coal, natural gas, or whatever), would still be used. I'd rather have a full EV, but for now, the plug-in hybrid is the best I can manage.
19. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
If we could even copy the Prius correctly we could make a lot of progress. The plug in crowd continues to ignore the 38% efficient engine of the production Prius (Argonne data available if anyone cares.) Then they fail to notice that the Prius method where there is a direct mechanical link from the engine to the wheels which avoids the generator loss, battery loss, and motor loss. The mechanical link has some loss though even the electric motor has to be linked to the wheels. Even worse, sticking batteries in a Prius as the 100+mpg crowd does actually degrades the Prius engine to 32%. ( Argonne data exists on this point also.) The biggest disaster of all is that the plug-in crowd would have us believe that the source fuel for electricity can be ignored in their mpg quotes. How embarrassing is this? Of course there is the dream that solar or wind is going to get done in massive quantities. And then we are subjected to the economic trick where the evaluation of cost feasibility is based on subsidized costs, and usually the cost of money is ignored. Think about how our electric bills will look when we are all getting subsidies from ourselves. And then the federal budget will stagger under the load, even more than it is staggering now.
18. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
#17....you still drive a SCOOTER. This is a car that can carry someone in comfort. I get great gas mileage on my $700 bicycle too but thats also irrelevant
17. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I drive a $2000 Ego-vehicle all-electric scooter and get the same range as the $30,000 Prius with a $10,395 Hymotion plug-in conversion. I get the same range and commute every day. For the money the "green" doofusses are spending, I could get 20 scooters. Of course now that gas is back to $2 a gallon, the payback period for electric vehicles is approximating the expected time before the sun goes super-nova. Happy motoring!
16. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
To address #15s questions: "How does the plug-in compare to the non plug-in Prius?" For the moment ignore production efficiency. A gallon of gasoline contains 36.6kWh of energy. At an EPA highway 45 mpg, that works out to 813 Wh/mile. At 4-5mi/kWh, the Prius (or Volt) on electric uses ~200-250 Wh/mi. The average speed of the EPA test is 48mph. At 48 mph the mechanical energy required to sustain the Prius' speed is ~186Wh/mile. While the thermodynamic efficiency of the Prius' ICE may be reduced by its lower duty cycle of use in a PHEV, the fact that its only providing ~10-20% of the cars motive power during that cycle makes that small change fairly irrelevant as much less gas will be used overall. Once the battery is depleted on longer trips the ICE will return to its original duty cycle and efficiency. Electric generation and distribution can be as low as ~30% as you say. It can also be as high as 100% using decentralized renewables. Even if you double or triple the electrical operation number to account for the poor efficiency of these older plants and add an appropriate overhead for gasoline production, electric still comes out better than burning gasoline. It does illustrate though that while a move towards pluggins is a good start, it must be met by equal pressure to move the electric industry towards more efficient and cleaner sources for major longterm gains to be made. That may not be as hard to do as many would think though. With the incentives available 1/1/09, you could install a solar array with capacity to drive a PHEV Prius or Volt 40 miles a day (~2.3kW DC) for 20+ years for ~$3,300. That works out to 1.14c/mile. Even if you financed it to avoid the upfront cost and doubled the overall cost, 2.3c/mile is still way better than the 6.5c/mile you pay for gas in a Prius at $3 a gallon, or even the 4.3c/mile at $2 a gallon. Having your gas price locked for 20+ years at the equivalent of $1.05 per gallon, and magically contain virtually no GHGs or smog emissions and be 100% domestic (on your own roof) sounds pretty good to me.
15. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
#9 appropriately bases comparisons on btu of heat and lbs CO2, though key problems of that post are: (1) Charging is at night to get the low electric rates and this night time electricity is generated the power generating capacity that costs the least to operate. This is conventional coal power which operates at 32% efficiency on average in the USA. (On the national stage, there is not much coal gasification going on, whatever that might be.) (2)Certainly the average car is a horrible waste of energy. The interesting question is, "How does the plug-in compare to the non plug-in Prius?" I wonder if the Hymotion people make it clear that the Argonne tests of the "Engine efficiency on UDDS Cycle" showed average engine efficiency of 32.6% for the Hymotion modification compared with 38.2% for the Production Prius. Cars such as the Aptera and Miastrada (my project) show ways to make a much more important change to the automobile world. Both utilize electric equipment. However, these projects show the kind of results that are needed. Plugging in a car is not a bad thing to do, but it does not accomplish very much. These efforts should not cause a sense of complacency.
14. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I live in a big city, and a LOT of people drive less than ten miles to work; the majority, however, drive around 22 miles to work - theres a well known suburb to the west of the city, and most of the middle class persons drive on a freeway from that suburb to the city. If those people could charge their car at work, and they had one of these upgraded Prius', then they would use very, very little gas - gas is always needed for acceleration; electricity can accelerate like theres no tomorrow, but it would drain even one of these big-ass battery packs very quickly. But if a hundred thousand people or so in a city could get to work and back while using less gas than could fill a can of soda (330ml), then pollution goes down, oil use goes down, noise would go down slightly, all while achieving the same goal - to get to work on time.
13. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Actually, it IS all about saving money, since man-made global warming is simply the latest in a string of "sky is falling" HOAXS put on people over the last 40 years (in the 70's, it was the "impending ice age" (source, national geographic). Make it pay and people will be all over it.
12. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I run a Hymotion pack in my prius - I would expect an OEM product to be more integrated in terms of meeting the peak efficiency requirements of the engine to the battery but that being said - I still maintain fuel economies in the upper 80's and lower 90's and I've trimmed out the aerodynamics to keep 100+ at 65 mph - so I guess it's about enabling growth and stirring up the pot more than improving the tiny fleet of vehicles that have taken on the kit. I believe the future includes both fuel and electricity as part of a balanced drive and I will happily pay a price to help sponsor that change.
11. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Well, electric drive is fundamentally efficient. Get used to it. Power plant turbines are up to three times as efficient as your typical car engine, in typical car usage. So, there is plenty of margin for transmission line, battery and motor losses, and still come out twice as efficient, and 6 times cheaper. Now, the difference in Prius engine efficiency is due to the Prius engine being run at lower power. But this does not mean that more overall energy used by the Hymotion Prius. Its very possible to degrade engine efficiency to 10%, if the engine only pushes the car 100 yards, on a 20 mile trip, and still have that car use less energy.
10. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Website: www.peakoilgarage.com
I have had a Hymotion system installed for about 3 weeks now. My average MPG was also about 85 mpg initially. After about 1 week of experience, my average is now above 99.9 mpg. In pure EV mode (under 35 mph) it will go about 22 to 25 miles. At highway speeds of 55 mph, the Hymotion system will last about 40 to 45 miles and provide about 150 mph ave fuel consumption. Then it converts to standard Prius mode. Experience counts when using the Hymotion system. It takes a few days to learn how best to use the extra electric power.
9. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Sorry, but there is really no question about the vastly improved energy efficiency possible with electric vehicles. The only shell games in town are those being played by the oil companies. A recent study by the DOE estimated the well to wheels BTU efficiency of conventional and hybrid gas electric vehicles, comparing them to fuel cell vehicles fed by coal gasification. Their numbers were 5,900 btu/mile for an average 2005 gasoline car, and 4,200 btu/mile for a 2005 gas/electric hybrid. The fuel cell vehicle was estimated (in an ideal lab environment) at 5,100 btu/mile in 2005, and they are hoping to hit 3,200 btu/mile by 2030. Unfortunately they don't include full electrics in the same paper, but we can take a pretty good wag at a comparable value. A modern combined cycle natural gas or coal electric plant runs at about 7,000 btu/kWh. US average transmission and distribution loses are around 7.2%, so lets add 25% overall for transmission and charging inefficiencies. That gets us to 8750 btu/kWh. Electric car efficiencies range from about 3-5 miles/kWh. The Volt mentioned above is coming in at ~40 miles/8kWh or ~5 kWh/mi, the Prius has been found to be right around there as well or even a little better. So 8750 btu/kWh / 5 miles/kWh = 1750 btu/mile. So even on natural gas and coal, an electric (PHEV or BEV) is more than 3 times as efficient as an average car, almost 2.5 times more efficient than a hybrid, and almost twice as efficient as they hope a fuel cell will be in 20+ years. From a CO2 perspective, a modern coal plant emits ~1.8 lbs/kWh, natural gas about 1.0 lbs/kWh. With 19.6 lbs released per gallon of gas, coal is the equivalent of 54mpg, natural gas 98 mpg. When you look at solar, wind, hydro, nuclear etc the picture gets even better for electrics in terms of both btu and CO2 efficiency.
8. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
It all depends on your priorities. If your focus is on reducing our dependence on foreign oil, or oil in general, MPG is still a very valid measurement. It accurately shows the reduction in gasoline consumption. The problem with any sort of alternative accounting, is that it is highly dependent on assumptions which make it very susceptible to bias. Where do you assume the electricity comes from? How do you determine equivalence? BTUs? Lbs of CO2? Lbs of NOx? Lbs of SOx? In my mind the beauty of PHEVs and eventually BEVs is that you have a choice about where to get the electricity from. A car that drives on gas is 100% dependent on oil. A car that drives on electricity can be powered by coal, nuclear, natural gas, hydro, solar, wind, methane, biofuels etc. That flexibility has a lot of inherent advantages with regards to pollution, cost and energy independence. Thats not to trivialize the importance of keeping pressure on the electric industry to expand their use of renewable, but at least the option is there unlike the current petroleum dominated situation.
7. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Here in Massachusetts the cost for a KWH is 20 cents. So, it's going to cost you around a *buck a night to charge your A123 pack. 25 mile range? So it's 4 cents a mile? *(Not accounting for charging losses). Of course if you don't live in MA, charging up is going to cost you a LOT less.
6. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I am an owner of a Hymotion L5 unit. I am getting much better mileage than your test indicated. I am finding as it is getting colder the efficiency of the unit is going down. I am currently averaging 88 MPG on my second tank of gas since the middle of September. Calculating individual trips using the Multi Function Display on my 1st tank of gas ranged between 111 and 212 mpg. It is all in the way you drive the vehicle. Terrain, speed and distance traveled are also factors. You are right about payback. I calculated my payback as 29 years (since I already owned the Prius). IT IS NOT ABOUT PAYBACK. It is about doing what I can now to mitigate my personal contribution to global warming. The electricity I use to charge my Prius is 100% renewable (from solar panels on my roof). The car is home from work midday so there is enough sunlight to charge the pack.
5. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Website: http://www.miastrada.com
The writer of number 2 comment is nominated to the honest mpg club. Writer of number 1 is nominated to the electric car shell game club.
4. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
I looked carefully at the Argonne presentation labelled "SAE 2007 Congress" which shows side by side graphical data on engine efficiency, with the Hymotion Prius on the left side and the Production Prius on the right. The average engine efficiency for the Hymotion version is recorded at 32.8% and the Production Prius is 38.2%. I read this to say that the Hymotion arrangement significantly degrades the otherwise amazingly good performance of the production Prius. The widely misrepresented efficiency of electric operation creates such irrational enthusiasm that this fact seems to get overlooked. But far worse is the deception that electric operation is fundamentally efficient. Of course it is if run from hydro power, but the marginal response to each plugged in electric car will be added burning of coal for many years to come.
3. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Website: www.calcars.org
Great report. Of course, as they say, "your mileage may vary." For any trip where the car drives mostly on the highway when the engine doesn't have time to warm up, results will be worse. For a range of conditions, see the results posted by Google.org's RechargeIT program at http://www.google.org/recharge/experiment/ using the previous generation of Hymotion conversions -- 93.5 MPG average, 115.1 MPG for city trips. On the miles per gallon, the 100+MPG claim makes even more sense when you add the footnote "plus a penny a mile for electricity" (figuring about 125 Watt-hours/mile and 8 cents/kWh). -- Felix Kramer, Founder, The California Cars Initiative (CalCars.org)
2. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Isn't it about time we start using mileage estimates for plug-in hybrids that don't cheat? Calculating the amount of gas used isn't the whole thing. We should also include the electricity used. After all, if I push my car down the road while it is idling, it doesn't mean my car magically gets 300 mpg. Energy costs money regardless of its form. A plug-in hybrid has vast efficiency advantages over a conventional car, so why cheat? Report a figure that gives the total equivalent MPG, not just the amount of gas used. In that way, consumers can make an informed comparison.
1. RE: Plug-in Toyota Prius Hybrid Test Drive: Is 100 MPG Possible with A123 Systems Hymotion Kit?
Website: www.calcars.org
Great report. Of course, as they say, "your mileage may vary." For any trip where the car drives mostly on the highway when the engine doesn't have time to warm up, results will be worse. For a range of conditions, see the results posted by Google.org's RechargeIT program at http://www.google.org/recharge/experiment/ using the previous generation of Hymotion conversions -- 93.5 MPG average, 115.1 MPG for city trips. On the miles per gallon, the 100+MPG claim makes even more sense when you add the footnote "plus a penny a mile for electricity" (figuring about 125 Watt-hours/mile and 8 cents/kWh). -- Felix Kramer, Founder, The California Cars Initiative (CalCars.org)
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