Jul 11, 2005 (From the CalCars-News archive)
Q1: Why plug-in hybrids (PHEVs)?
A: Plug-in hybrids offer the best chance of transitioning away from fossil fuels towards a renewably powered transportation future. Full sized electric vehicles suffer from limited range and may require up to 3 times the battery capacity of an EDrive equipped plug-in hybrid and still not be capable of satisfying 100% of a personís driving needs. At present, hydrogen fuel cell powered vehicles suffer from astronomical cost (over $500,000), limited range (80-180 miles), low efficiency (compared to batteries) and most notably a lack of economically priced and widely available fuel. Plug-in hybrids however can be built today and provide a no-compromises solution that moves us away from fossil fuels.
While none of these solutions (including plug-in hybrids) can stand alone on an economic basis today, with rising fuel costs, improved battery performance and reduced battery cost, plug-in hybrids offer the best hope of becoming economically viable within the next 5 years. EDrive Systems LLC aims to prove the concept for those early adopters willing to show the world that vehicles can be renewably powered without compromise and that we can move towards a cleaner, more renewable future. Many others may choose PHEVs as a solution that can be powered by U.S. energy sources without paying the hefty price of supporting countries that might not have our best interests in mind.
In the future, plug-in hybrid gasoline cars may give way to plug-in hybrid ethanol or bio-diesel powered cars. If an economical, environmentally friendly source of hydrogen is ever discovered, plug-in hybrid fuel cell vehicles could provide a less expensive, more efficient, and less range limited solution than a pure fuel cell vehicle.
Battery solutions such as electric vehicles and the EDrive plug-in hybrid can turn over 80% of the source electricity into usable power for the wheels (after battery and charger losses). Creating hydrogen from water/electricity electrolysis and then compressing the hydrogen for vehicle storage and running the hydrogen through a vehicle fuel cell system may result in less than 20% of the source electricity reaching the wheels. Per unit of power, advanced lithium batteries are also less expensive than fuel cells, meaning that a vehicle with less fuel cell and more batteries would be less expensive. A plug-in hybrid fuel cell vehicle would also be less dependent on a sparse hydrogen infrastructure as most of the daily driving would come from the economical and convenient nightly home recharge.
No matter what the ultimate future renewable vehicle fuel may be, electricity will certainly play a major role. Plug-in hybrids build a bridge between any electrical source and any other vehicle fuel, providing many of the advantages of an electric vehicle with the long range and quick refueling offered by other fuels.
Q2: Doesn't plugging in the car just trade oil pollution for coal pollution?
A: Californians are spoiled by one of the cleanest electrical grids in the U.S., but even where coal supplies much of the electrical power, plugging in vehicles is still a smart environmental solution. One thing that is often overlooked when electric power plant pollution is discussed, is the upstream pollution required to extract oil, transport it, refine it, distribute the gasoline then refuel a vehicle (vapor emissions). Comparing the national electrical grid to the average gallon of refined gasoline shows that the upstream pollution for gasoline production on average is much higher than that of the average electricity source.
Plug in vehicles charge at night when electricity is cheapest and most widely available on the grid. While electricity may be produced by renewable or non-CO2 producing sources, fossil fuels at present cannot.
Q3: What is the EDrive system for the Toyota Prius and how does it work?
A: The EDrive system replaces the existing Prius NiMH battery and Toyota battery control computer with a larger Valence Saphion lithium-ion battery and a proprietary battery monitoring and control system developed by EnergyCS. The new system allows the Prius to be charged at home using a standard 110/120V home outlet. With the larger battery, the Prius can run in electric only 'EV' mode at lower speeds or when less power is needed. The result is EV driving and electrically boosted gasoline driving for the first 50 to 60 miles with a gasoline efficiency of 100 to 150mpg. After the 50-60 mile 'boosted' range, the vehicle performs just like a standard Prius until it is plugged in again. The battery system is approximately 3 times larger than the Toyota NiMH battery and is installed under the rear cargo carpet. A small display is mounted on the dashboard.
Q4: How do I activate these special EV modes?
A: The entire system is automatic. Just drive the car like a standard Prius and the EDrive system will use electricity whenever possible to reduce gasoline consumption.
Q5: What is the driving experience like with an EDrive equipped Prius?
A: After the nightly re-charge, the vehicle can be driven in EV mode until the vehicle speed exceeds 34mph. At this point the engine may start in order to warm up the emission control system. After the emission system is warmed up, the Prius will use the gasoline engine whenever higher speeds or power levels are needed, but will always (for the first 50-60 miles) inject electricity to reduce gasoline consumption. It is possible to drive in EV mode at speeds over 34mph and up to 55mph if the power requirements are low enough. The dashboard mounted display will always tell you if you are using gasoline and if not, how far you can press the accelerator without turning the gasoline engine on. In low speed city driving and 55mph freeway driving it is possible to average over 200mpg. More aggressive driving over 65mph will lower the efficiency to 100mpg or less. For example, 75mph freeway driving could result in less than 80mpg. During the 50-60 mile boost period, the Prius battery display will show either 7 or 8 green bars (ie full). After the boost mode, the display (and vehicle performance) will be identical to a standard Prius.
Q6: Why the big difference between 55mph and 75mph?
A: Because of the configuration of the Prius, electric use is limited to 21kW and often less. At speeds over 34mph, the electrical contribution is more or less constant. You may find at 55mph that 1/4 of the power is coming from gasoline and 3/4 from electricity, but at 75mph the contribution may be 2/3rd gas and 1/3rd electric. Even though the electric contribution is the same in both cases, the gasoline contribution (and thus mpg) can be dramatically different.
Q7: Can I really get over 200mpg with EDrive on my Prius?
A: Yes, but it requires low speeds (55mph freeway) and mild acceleration in city driving. Most Prius EDrive users will likely get closer to 100mpg.
Q8: How long does it take to charge?
A: The EDrive lithium battery system is 9kWh or kilowatt-hours (7 times larger than the Prius NiMH battery). The charger used by the EDrive system is 1 kilowatt (kw), about the same as a hair dryer. If the battery were totally depleted, it could take 9 hours (9hrs •1kW = 9kWh) to charge the battery.
Q9: Can the charger work on 240V power as well?
A: Yes, but the charge speed will be the same (1kW).
Q10: What is the EV driving range?
A: If you were to limit your speed to 34mph or less, the gas engine may not come on for up to 35miles.
Q11: How is the EV range so much larger than a standard Prius with only 7 times as much battery?
A: The standard Prius has a 1.3kWh NiMH battery but only uses about 25% of it (or 300Wh). The EDrive lithium battery is 9kWh but up to 80% of it is used (or 7200Wh). Therefore the EDrive system actually has 24x more energy (7200/300) at its disposal.
Q12: How much does it cost to charge the car?
A: A full charge could take 9kWh of electricity from the wall socket, but on days when the car is driven less than 50 miles, the electricity needed to re-charge will be less. If your electricity cost $0.10/kWh (about average) then a full charge would be just under a dollar.
Q13: What happens if I forget to plug in the car?
A: Then the vehicle will behave exactly like a normal Toyota Prius. (ie ~50mpg)
Q14: Is fast charging available? Can I use public EV charging spaces?
A: The EDrive system was designed for only a 1kW charger with the intent of being slow charged at night when spare electricity is most available on the grid. Unlike an electric vehicle that might need additional charging during the day, a plug-in hybrid can still be driven as a gasoline hybrid after the battery is depleted (50-60 miles into the day). EDrive is not planning to offer higher speed charging as it shouldnít be needed and would only increase the system cost.
Q15: Can more batteries be added to increase the electric/boost range?
A: EDrive was designed for 50-60 miles of boost as this was just beyond the average driving requirements for most consumers. Ideally the battery should be sized in order to balance utilization, cost and battery life. At 50-60 miles boost range, there will be many days when the battery is only 1/2 or 2/3rds used, which will greatly increase battery life.
Q16: Why were Valence Saphion Lithium batteries selected for EDrive?
A: The Valence Saphion technology provides a much safer lithium-ion battery than most standard manufacturers as the chemical composition dramatically reduces the risk of fire under extreme conditions (such as cell rupture during a severe collision). Additionally, the Valence lithium ion has shown much improved cycle life compared to competing manufacturers. Safety and long life are primary concerns for vehicle applications.
Q17: How long will the lithium battery last?
A: Testing indicates that the Valence batteries should last 6 to 8 years in an EDrive equipped Prius, with the possibility of 10 or more years being likely. Depending on how the 'end of life' is defined, the battery may last the life of the vehicle (ie if 30 miles of boost range is deemed sufficient from a system that initially provided 50-60).
Q18: How much does the EDrive battery weigh?
A: The EDrive battery pack weighs approximately 250lbs. The Toyota NiMH battery removed from the vehicle weighs over 70lbs. The net weight increase is thus approximately 180lbs.
Q19: What happens to the existing NiMH Prius hybrid battery?
A: It is removed during the EDrive system installation process.
Q20: Does the EDrive system affect any other part of the Prius (like the AC)?
A: Many of the Prius subsystems (such as AC) are already electric. The Prius was designed to have electric driving modes, EDrive merely enhances the existing system.
Q21: How safe is the EDrive option?
A: The EDie=C system is designed with safety in mind. The Valence Saphion lithium batteries provide exceptional safety and the rear battery pack is being designed so as to have minimal effect on the existing rear crumple zone in case of a collision.
Q22: When can I get EDrive installed in my 2004/05 Prius?
A: Our goal is to have the commercial EDrive product available in early 2006.
Q23: Where can I get EDrive installed in my 2004/05 Prius?
A: Initially, all installations will be done at Clean-tech in Los Angeles.
Q24: Will it be available outside of California? When?
A: As far as the U.S. market is concerned, we are concentrating on Southern California first. Within 9 months of the initial sales in L.A., additional authorized retail/installation locations will be set up in other parts of the country.
Q25: How long does it take to install EDrive in a Prius?
A: It should be possible to install an EDrive system in your Prius in less than one business day.
Q26: How much will the EDrive conversion cost?
A: Our goal is to offer the conversion to consumers at under $12,000. Final pricing cannot be determined until the commercialized version has been developed.
Q27: Is EDrive available as a user-installed kit?
A: No. Only EDrive certified and trained installers will be installing systems. The installation involves working with high voltage and sensitive electronics which require specialized training.
Q28: How does this affect my Toyota Warranty?
A: If a warranty claim were disputed by Toyota, Toyota would be responsible to show how the modification caused the problem. As the EDrive system never touches anything under the hood of the car (engine, motors, hybrid controller etc) it is not clear how this would be handled. Fortunately being a Toyota product, the Prius has shown to be an extremely reliable vehicle and we don't anticipate any changes in reliability with the EDrive system installed.
Q29: What will be the Warranty on the EDrive system?
A: The warranty for the EDrive installation, electronics and Valence batteries is yet to be determined. The details of the warranty will not be known until the commercial product is released.
Q30: Will EDrive work on Honda hybrids?
A: While it may be possible to inject some electrical energy into the Honda IMA system, because the Honda motors and battery system are less powerful than the Toyota Hybrid Synergy Drive system and offer no EV mode capability, the performance improvement from plugging in would probably be lower.
Q31: Will EDrive work on pre-2004 model Prius vehicles?
A: There are no plans at this time to offer EDrive for pre-2004 Prius.
Q32: What other hybrids will EDrive be available for? When?
A: Following the roll-out of the commercial EDrive system for Prius, EDrive aims to bring this exciting technology to other 'full-hybrid' vehicles such as the Ford Escape hybrid, Lexus 400h and Toyota Highlander hybrids.
Q33: Can EDrive be installed on non-hybrid vehicles?
A: EDrive makes use of the existing full hybrid system on vehicles like the Toyota Prius. There are no plans to offer EDrive options for vehicles that do not already incorporate a full hybrid drive system.
Q34: How is Toyota involved?
A: Toyota has not been involved in the development of the EDrive system for the Prius and is not presently involved in EDriveís efforts. Toyota has not endorsed EDrive nor has Toyota discouraged it (aside from warranty issues yet to be discussed). We suspect Toyota is as curious as we are about how the early plug-in hybrid market will develop.
Q35: Is there any way to add solar power to the EDrive system?
A: While solar panels integrated on a vehicle roof could partially recharge the batteries during the day (3-4 miles of additional range) on a Toyota Prius, this might degrade the vehicle aerodynamics significantly. Home rooftop solar could allow EDrive customers who choose to install such systems to harvest a large portion of their vehicle power from renewable solar energy. Similarly, those who have the option of buying renewable power for their homes can use the clean power to displace gasoline with an EDrive system.
Q36: How is EDrive Systems LLC associated with CalCars?
A: EDrive Systems LLC is not in any way associated with the California Cars Initiative (CalCars). Unlike EDrive, EnergyCS and Clean-Tech, CalCars is a non-profit advocacy group and is not involved in technology development. We fully support the advocacy and outreach efforts of CalCars to raise public awareness of the benefits of plug-in hybrids, but there is no financial relationship between EDrive Systems LLC and CalCars.
Q37: Is the EDrive system gas-optional? (ie: a GO-hybrid)
A: No. While the historical definition of a plug in hybrid might be closer to that of an electric vehicle with a gasoline range extender, the EDrive system takes advantage of the sophisticated full hybrid systems in vehicles like the Toyota Prius and Ford Escape hybrid. As such, the system is not presently designed to be fully capable at any speed in EV mode, but rather to share the burden between gasoline and electricity depending on vehicle operating requirements and operator demands. In the future, we anticipate the electrical contribution growing and the gasoline contribution shrinking, but at the moment the EDrive system for the Prius is not really gasoline optional.
Q38: Will EDrive Systems, EnergyCS or Clean-Tech become a publicly traded company?
A: At the present time there are no plans for any of the EDrive partners to go public.
Note: If you have additional questions, please e-mail us at mailto: info@.... Your question may then be included in our next update of this FAQ page.
Disclaimer: Specifications of the commercial EDrive system for the 2004 and later model year Prius are subject to change without notice. The questions and answers in the FAQ do not constitute a specification for the EDrive system.