DAY THREE: Sep. 6th, 2008 - Saturday.
Day three of the Santa Rosa Junior College Course -
DET-193. ELECTRIC VEHICLE CONVERSION.
The class gathered for the third session of this new course, taught by Peter Oliver of Make Mine Electric.
We carried out a skill's assesment to assist with the non-EV work necessary on the two cars in the workshop that need to be finished and moved out. Peter asked for a show of hands of those who were comfortable with such things as low and High voltage troubleshooting, disc brake repair, suspension, welding ect.
Then discussed the fact that immediate, personal economic justifications for EV difficult at this time - most people have non-economic reasons for doing this. Peter showed a series of .pdf slides by Steve Ekensen (?) entitaled - "Why EV?" [Will ask permission to post]
Peter pointed out that the largest consumer of Electricity are the oil refinerys. ie we could use that electricity to directly power vehicles.
Thin film BIPV solar panels - still expensive and not terribly efficient, but up and coming. Talked alof German experience of guaranteeing the buy-back of localy generated electricity which has exceeded all expectations.
Mentioned smart plugs and smart meters for the Vehicle-to-grid (evpropulsion) concept of buying back power from EV's during peak hours. Requires a paradigm shift so that Power companies become more of a management operation rather than a generating company.
Components in an EV:
Batteries: Stores energy
BMS: monitor state of batteries - charging, temp., balances cell states, etc., monitors for Dangerous condtions.
Relays: Control many functions
Motor: moves car
Instrumentation: Amps being used / state of charge / battery temp. guage (at positaive terminal or measure groups of batteries in a box etc.)/ speedo / Tachometer
(Analog meters more user friendly than digital)
Controllor: provides and controls energy to motor.
Charger: Recharges batteries from multiple AC volts, to DC voltage.
Pot box: takes inputs from driver and processes through controllor to control speed (like accelerator pedal).
DC-DC: Transforms high voltage from DC traction pack to 12v to run vehicle electrics. Consider wattage needs of he vehicle.
Brakes/Steering: Vacum operation - power steering considerations.
Drive train / transmission: Direct Drive vs
Climate Control: Ceramic heaters for defrosters, compressors for A/C
See Anatomy of an EV by Shari Prang (membership required to read the entire article on the Home-Power site).
Peter then presented a spread sheet that he uses to compare costs of and ICE vs the EV. There are many variables in all aspects - miles driven in the average ICE vs an EV, cost of maintence varies greatly from car to car, etc.
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Chris Jones president of North Bay Electric Auto Association in Sonoma County, who converted his 1966 Mustang, joined the class after lunch.
He showed their website (http://www.nbea.org) and discussed their Open Scource Eleltric Vehicle (OSEV) project and other activigties of the club. Shared his reason for and experiences with EV, especially his experience with early battery technology (which is havig a good ending as Valence is offering to replace his entire traction pack as they have not lasted as well as expected. This is a powerful indication of the importance of Chris and the NBEAA in the EV field since Valence has recognized that their reputation could be at stake..
Chrise Discussed four of the Club member's car in more detail (see the NBEAA web site for members cars): Chris Jones, Don Price, Peter Olver, and showed the OSEV project parameters.
The class then went out and Chris showed his EV Mustang showing what was in it and how it was put together.
Returning to the class Chris ran through the difference between the DC and AC motors on the white board, and outlined the functions of the Controller in DC and AC systems.
Returning to the workshop, Chris then outlined what needs to be done to get Dons Price's 1988 Horizon ready for the referbishment. Don passed the car on to the SRJC before he died in 2007, and the idea is update it and auction it off to raise funds for the SRJC EV course.
Much non-EV work also has to be done on brakes, suspension and the like, so we will work on that first.
(See pluginamerica web site for discussion of where manufactures are with thier plans for EVs and Hybrids)