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Difference between revisions of "Talk:EAA-PHEV PRIUS Documentation"
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History. I was the technical lead for CalCars 2004 PRIUS+ modification of | History. I was the technical lead for CalCars 2004 PRIUS+ modification of | ||
− | my 2004 Prius into a pluggable hybrid (PHEV). | + | my 2004 Prius into a pluggable hybrid (PHEV). (I remain CalCars' technical |
− | founder, enlisted me in mid-2004, shortly after I first contacted him. The | + | lead.) Felix Kramer, CalCars founder, enlisted me in mid-2004, shortly |
− | project had a lot of internet collaboration as well as physical volunteer | + | after I first contacted him. The project had a lot of internet |
− | help, largely from Electric Automobile Association (EAA) members (thanks to | + | collaboration as well as physical volunteer help, largely from Electric |
+ | Automobile Association http://www.eaaev.org (EAA) members (thanks to | ||
everyone). You can view much of the history of the project at | everyone). You can view much of the history of the project at | ||
− | http://autos.groups.yahoo.com/group/priusplus/messages. | + | http://autos.groups.yahoo.com/group/priusplus/messages, especially the |
+ | summary at http://autos.groups.yahoo.com/group/priusplus/message/421. (This | ||
+ | group is currently closed to new members, but postings are viewable by | ||
+ | non-members.). | ||
− | Greg Hanson offered EnergyCS help at low cost. They had a CAN bus | + | Greg Hanson Hanssen offered EnergyCS help at low cost. They had a CAN bus |
controller that they turned into a battery management computer to replace | controller that they turned into a battery management computer to replace | ||
Toyotas Battery ECU by emulating that OEM computers CAN messages to the | Toyotas Battery ECU by emulating that OEM computers CAN messages to the | ||
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Greg and others at EnergyCS then got excited, built their own Prius | Greg and others at EnergyCS then got excited, built their own Prius | ||
conversion using Valence Li-ion batteries, and with CleanTech, a company | conversion using Valence Li-ion batteries, and with CleanTech, a company | ||
− | to which Felix introduced them started EDrive Systems to commercialize | + | to which Felix introduced them started EDrive Systems |
− | Prius PHEV conversions. This is an exciting development, which may provide, | + | http://www.edrivesystems.com to commercialize Prius PHEV conversions. This |
− | for most people, the first opportunity to own a PHEV. | + | is an exciting development, which may provide, for most people, the first |
+ | opportunity to own a PHEV. | ||
However, there is also a community of experimenters, schools, and others | However, there is also a community of experimenters, schools, and others | ||
Line 28: | Line 33: | ||
started experimenting with higher voltages of PbA batteries and came up with | started experimenting with higher voltages of PbA batteries and came up with | ||
an algorithm for fooling the Battery ECU in an organized way. It has so far | an algorithm for fooling the Battery ECU in an organized way. It has so far | ||
− | been tried only with PbA batteries, and only with manual control, but I hope | + | been tried only with tried it first with PbA batteries, and only with manual |
− | and | + | control, but I hope and expectexpected it to work more generally. It will |
+ | be described in detail below. | ||
Line 46: | Line 52: | ||
calculate it against. At low SOC, however, the internal resistance is >500 | calculate it against. At low SOC, however, the internal resistance is >500 | ||
milliohms, too high for full hybrid functionality. My PRIUS+s performance | milliohms, too high for full hybrid functionality. My PRIUS+s performance | ||
− | has been documented in CalCars PRIUS+ Fact Sheet, available at | + | has been documented in CalCars PRIUS+ Fact Sheet, the latest version of |
− | http://www. | + | which is always available at http://www.CalCars.org. |
− | provide for approximately double the normal Prius gasoline mileage for | + | http://www.calcars.org/priusplus.html In short, the BB Batteries weigh about |
− | around 20 miles of mixed (town and highway) driving on each charge. | + | 260 lb and provide for approximately double the normal Prius gasoline |
+ | mileage for around 20 miles of mixed (town and highway) driving on each | ||
+ | charge. | ||
Next, we planned on installing a NiMH pack, largely to prove that the | Next, we planned on installing a NiMH pack, largely to prove that the | ||
Line 55: | Line 63: | ||
capable of powering electrically and economically effective PHEVs; thereby | capable of powering electrically and economically effective PHEVs; thereby | ||
removing one more auto company excuse for not building them. After that, we | removing one more auto company excuse for not building them. After that, we | ||
− | + | wouldAs soon as we have the people-resources, we will move on to work with | |
− | work to ensure proper cell-by-cell charge and discharge control as well as | + | one or more of th newer high-performance Li-ion suppliers, which we expect |
− | to engineer out any likelihood of thermal runaway problems, to which this | + | to require additional engineering work to ensure proper cell-by-cell charge |
− | chemistry is prone. | + | and discharge control as well as to engineer out any likelihood of thermal |
+ | runaway problems, to which this chemistry is prone. | ||
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cells, providing plenty of failure points. While looking only at | cells, providing plenty of failure points. While looking only at | ||
technologies that are in production, if only in the early stages, CalCars | technologies that are in production, if only in the early stages, CalCars | ||
− | has begun discussions with more than one specialty Li-ion | + | has begun discussions with more than one specialty Li-ion manufacturers with |
lines of high-power-capable Li-ion cells. | lines of high-power-capable Li-ion cells. | ||
− | CalCars and Electro Energy, Inc, in Danbury, Connecticut, are now in the | + | CalCars and Electro Energy, Inc http://www.electroenergyinc.com/, in |
− | late stages of a joint project to adapt their unique form of NiMH packs to | + | Danbury, Connecticut, are now in the late stages of a joint project to adapt |
− | the PRIUS+. As part of the project, I have designed control circuitry that | + | their unique form of NiMH packs to the PRIUS+. As part of the project, I |
− | is specific to the characteristics of this battery as well as Toyotas BMS. | + | have designed control circuitry that is specific to the characteristics of |
− | When complete (expected yet this first quarter of 2006), the pack should | + | this battery as well as Toyotas BMS. When complete (expected yet this |
− | weigh about the same as the BB Battery pack but last for 40-50 miles of | + | first quarter of 2006), the pack should weigh about the same as the BB |
− | mixed driving. Internal resistance figures we have seen so far are in the | + | Battery pack but last for 40-50 miles of mixed driving. Internal resistance |
− | 200 milliohms range. It is possible that Electro Energy will elect to sell | + | figures we have seen so far are in the 200 milliohms range. It is possible |
− | this pack to experimenters, so stay tuned. | + | that Electro Energy will elect to sell this pack to experimenters, so stay |
+ | tuned. |
Revision as of 07:16, 22 January 2006
History. I was the technical lead for CalCars 2004 PRIUS+ modification of my 2004 Prius into a pluggable hybrid (PHEV). (I remain CalCars' technical lead.) Felix Kramer, CalCars founder, enlisted me in mid-2004, shortly after I first contacted him. The project had a lot of internet collaboration as well as physical volunteer help, largely from Electric Automobile Association http://www.eaaev.org (EAA) members (thanks to everyone). You can view much of the history of the project at http://autos.groups.yahoo.com/group/priusplus/messages, especially the summary at http://autos.groups.yahoo.com/group/priusplus/message/421. (This group is currently closed to new members, but postings are viewable by non-members.).
Greg Hanson Hanssen offered EnergyCS help at low cost. They had a CAN bus
controller that they turned into a battery management computer to replace
Toyotas Battery ECU by emulating that OEM computers CAN messages to the
rest of the hybrid system. This system, though proprietary, got our PRIUS+
working quickly; first smoke-tested in late September, it was working well
by early November 2004.
Greg and others at EnergyCS then got excited, built their own Prius conversion using Valence Li-ion batteries, and with CleanTech, a company to which Felix introduced them started EDrive Systems http://www.edrivesystems.com to commercialize Prius PHEV conversions. This is an exciting development, which may provide, for most people, the first opportunity to own a PHEV.
However, there is also a community of experimenters, schools, and others interested in doing such modifications themselves, and the EnergyCS controller is not available for this purpose. Fortunately, Dan Kroushl discovered and shared the information that a higher-voltage battery is capable of fooling Toyotas Battery ECU into giving a higher SOC reading. I started experimenting with higher voltages of PbA batteries and came up with an algorithm for fooling the Battery ECU in an organized way. It has so far been tried only with tried it first with PbA batteries, and only with manual control, but I hope and expectexpected it to work more generally. It will be described in detail below.
Battery pack. I specified a BB Battery PbA battery pack (18 EVP20-12B1
modules from http://www.electricrider.com/batteries.htm) for our first
conversion attempt, in order to go through our learning curve with
inexpensive, fairly indestructible batteries. This turned out to be an
excellent decision, as, though it required replacement after 200 cycles and
just under a year, this pack has sustained our PRIUS+ through over a year of
work on finding a more advanced battery pack. The BB electric bicycle
batteries, though very marginal for this application, are actually quite
remarkable among PbA batteries. When fully charged, these 20Ah (12Ah @ ½
hour rate) batteries have a lower internal resistance (~250 milliohms) than
the OEM battery (300-350 milliohms) and are capable of supplying the Priuss
maximum draw of 200A a 10C or 17C rate, depending on which capacity you
calculate it against. At low SOC, however, the internal resistance is >500
milliohms, too high for full hybrid functionality. My PRIUS+s performance
has been documented in CalCars PRIUS+ Fact Sheet, the latest version of
which is always available at http://www.CalCars.org.
http://www.calcars.org/priusplus.html In short, the BB Batteries weigh about
260 lb and provide for approximately double the normal Prius gasoline
mileage for around 20 miles of mixed (town and highway) driving on each
charge.
Next, we planned on installing a NiMH pack, largely to prove that the chemistry that is already in all of todays mass produced hybrids is also capable of powering electrically and economically effective PHEVs; thereby removing one more auto company excuse for not building them. After that, we wouldAs soon as we have the people-resources, we will move on to work with one or more of th newer high-performance Li-ion suppliers, which we expect to require additional engineering work to ensure proper cell-by-cell charge and discharge control as well as to engineer out any likelihood of thermal runaway problems, to which this chemistry is prone.
I also looked at many Li-ion possibilities. The least expensive option is
currently 18650 cells, produced in huge volumes for laptop computers.
However, these, like the sub-C NiMH cells, are very small (2-2.8Ah). Also,
they are typically designed for 2-5 hour discharge rates and lack high power
capabilities. One pays more for high power, low susceptibility to thermal
runaway, and long cycle life and you still have to parallel many cells to
reach the necessary capacity. A typical PRIUS+ pack would use at least 1200
cells, providing plenty of failure points. While looking only at
technologies that are in production, if only in the early stages, CalCars
has begun discussions with more than one specialty Li-ion manufacturers with
lines of high-power-capable Li-ion cells.
CalCars and Electro Energy, Inc http://www.electroenergyinc.com/, in Danbury, Connecticut, are now in the late stages of a joint project to adapt their unique form of NiMH packs to the PRIUS+. As part of the project, I have designed control circuitry that is specific to the characteristics of this battery as well as Toyotas BMS. When complete (expected yet this first quarter of 2006), the pack should weigh about the same as the BB Battery pack but last for 40-50 miles of mixed driving. Internal resistance figures we have seen so far are in the 200 milliohms range. It is possible that Electro Energy will elect to sell this pack to experimenters, so stay tuned.