ev conversion 101 - wordpress.com · 60 km max city range ... very high torque and power potential!...
Post on 04-Apr-2018
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EV 101 Overview
● The Electric Japanese Mini Truck
● Safety
● Why DIY EVs? Why Not?
● DIY EV Expectations
● EV Components
● Range and Performance Estimation
● Example build
● Questions
The Electric Japanese Mini Truck
● 1992 Daihatsu Hijet Jumbo Cab
● Joint project with John Storey Bishoff
The Electric Japanese Mini Truck
● Then
● 660cc 3 cylinder gas motor, about 45hp● 4wd, 5 speed transmission● 7 L/100km fuel economy (42mpg)
● Now
● 45hp three phase AC motor● 7.6kWh lithium battery pack● 60 km max city range● 85 km/hr top speed
The Electric Japanese Mini Truck
● Joint project, shared use truck
● Started February 2010
● Licensed in Spring 2012
● 1000 + hours and counting!
● $14,000 total cost including the truck
● $0.01/km electricity cost to drive
● Very fun to drive! Great for hauling stuff
Safety Disclaimer!
● DIY EVs can be dangerous
● Fire ● Electrocution● Crush injuries, you name it!
● 0.2A across your heart can kill you
● EV batteries can often provide >1000A!
● High voltage increases shock potential
● Wear gloves when doing any wiring and don't become part of a circuit!
● Keep yourself and others around you safe
Why DIY Conversion?
● Potentially cheaper than Production EVs
● More vehicle selection
● Vehicle confguration is only limited by your imagination (and your wallet)
● High performance potential
● Satisfying hobby, with a conscience!
● The more people who see EVs as viable the more they will grow
Why Not DIY Conversion?
● Potentially more expensive than Production EVs
● Can be time consuming to convert
● Will you actually fnish this project?
● Vehicle reliability is limited by your skill
● Low performance potential
● Can be technically diffcult
● Like any DIY project there is potential for safety hazards!
Vehicle Type1. How many passengers?
● Any kids on the way?
2. How much cargo?
● Do you need to haul more than groceries?
3. What type of driving?
● City vs. Highway
4. Has it been done before?
5. What do you want to drive?
● Do you want to invest $20,000 in a beater?
Range Expectations
1. How far do you really need to drive in a day?● EVs are great for commuting! ● 50km = easy, lower cost● 200km = possible but getting quite expensive
2. Could you charge at work?
3. Longest daily drive has to be less than 80% of your maximum range!
Performance
1. Top speed
● Aerodynamics● Gearing● Max motor RPM● Power
2. Acceleration
● Weight● Gearing● Torque● You want 0.5G min off the line!
Budget
● What's the maximum you're comfortable spending on this project?
● Donor cost vs. parts cost; is the vehicle worth spending a lot of money on?
● Can you meet your range and performance expectations with your selected donor vehicle and budget?
● Can you sell parts removed from the donor?
● Could you share the project with a friend?
Tools, Facilities and Skills
● Tools you'll need● Full set of typical mechanics and fabrication tools● Voltmeter, Electrical crimpers and wire stripper
● Tools that will be good to have or borrow● Welder, drill press, band saw● Engine hoist
● You'll need an enclosed garage with good lighting and a heater
● Skills● Can you do basic car maintenance?● Do you have a basic knowledge of electricity and wiring?● Do you have access to a friend who can lend a hand?
EV Components
● Motors
● Adapters and drivetrain
● Controllers
● Batteries
● Battery Management Systems
● Chargers
● Auxiliaries
● DC-DC converter● Vacuum Pump● Power Steering● Heater
AC Motors
● Smooth power and control, easy reversing
● No maintenance, high effciency
● Full torque regenerative braking
● Limited options, DIY versions are less powerful and more expensive than DC motors
● One main brand for DIY, HPEVS motors with Curtis AC controllers
DC Motors● Very high torque and power potential!
● Lots of size and brand options, less expensive than AC for a given power output
● Most types can not provide regenerative braking
● Brushes require some regular maintenance
● Brands include NetGain Motors, Advanced DC, D&D Motors, Kostov
Adapters and Drivetrain
● Adapters
● Attach the motor to the transmission input shaft
● Can be purchased or custom machined
● But, alignment is critical!● Drivetrain
● Standard transmission vs. direct drive
● 4wd can work, but expect less range
Motor Controllers● Higher Amps = Higher Torque
● AC
● Curtis 650A, 60 - 130V max● 75kw max power ● PC programable
● DC
● Evnetics Soliton Jr. - 600A, 9-340V max ● Soliton 1 – 1000A, 9-340V max ● Soliton Shiva – 3000A, 425v, 1.2MW!● PC programable, liquid cooled ● Other brands include Curtis, Netgain
Controls, Zilla
Batteries
● Typical Pack Voltage 96V-144V
● Lead Acid
● Heavy● Low effciency (60%)● Low usable capacity ● Wear out quickly (500 charge cycles)● Some types need maintenance● Cheap, easy to implement● Work well for lawn tractor or quad
conversions
BatteriesLithium Iron Phosphate
● Best chemistry for DIY conversions
● 1/3 the weight for double the usable capacity of lead!
● Effciency from 88%-95%● >1500 charge cycles if you
typically discharge to 80% DOD.● 3.2V/cell● Popular brands; CALB, Winston,
Sinopoly, Headway
Batteries● Lithium Iron Phosphate
● Don't Overcharge!● Don't Over Discharge!● Don't charge below freezing● Safe to use at -30 but
performance is poor! ● Highly recommended to use a
BMS (Battery Management System)
Battery Management Systems
● Monitor individual cells to prevent overcharging
● Bleed energy off high cells to balance the pack
● Provide warnings to prevent over discharging
● Helps diagnose a weak or defective cell
Battery Chargers
● Start under $500 for a simple 1.5 kW charger
● Up to 12 kW chargers available
● Small packs can charge off 120 V but larger packs need a 240 V charger
● Popular brands include Elcon, Manzanita Micro, Zivan, DeltaQ
Auxiliary Components
● Large vehicles need power brakes and power steering
● Electric vacuum pump for power brakes● Electric hydraulic pump for power steering
● DC-DC converter provides 12 V to power your vehicle's systems
● Electric Heat
● Use a ceramic heater core, 3000 W minimum● Heated seats only draw 60 W each! Add on kits
are available● Potential to preheat your vehicle while it's
plugged in
Performance Estimation
● You want 0.5G acceleration!
● If you could maintain 0.5G acceleration up to 100km/hr you would get there in 5.7 sec!
● Motor torque x gear ratio = wheel torque
● Wheel torque ÷ tire radius = forward thrust
● Forward thrust ÷ vehicle weight = acceleration in Gs
● At what speed does the motor torque decrease?
● Use this to size your motor and controller
Estimating Range and Sizing the Pack
● Gas Car Effciency:● Only 14-16% in the city!● 20-26% on the highway
● Gasoline energy content = 9.63 kWh/L
● Electric car effciency: 80-90% !
● Use this to estimate the electrical energy needed to drive an EV a given distance
● Size the pack or estimate range with this value
Example Build: Toyota Echo Hatchback
● Pro's
● Lightweight – 2080 lbs● Aerodynamic – 0.29 drag
coeffcient● 4 doors● Inexpensive to buy used● Reasonably modern● Simple reliable car
● Cons
● Not terribly exciting! Yet....
Vehicle Type
1. How many passengers? (4)
● Any (more) kids on the way? (Not Yet)
2. How much cargo? (Just Groceries)
● I can use the mini truck for larger cargo
3. What type of driving? (City)
4. Has it been done before? (Yes!)
5. What do you want to drive?
● A Tesla Model S.....
Range Expectations
1. How far do you really need to drive in a day?● Spruce Grove and back safely = 60 km highway
2. Could you charge at work? (Potentially)
3. Longest daily drive has to be less than 80% of your maximum range!
● No problem, typical day <40 km
Performance
1. Top speed (120 km/hr)
● Aerodynamics (good)● Gearing (5 spd manual)● Max motor RPM (6500)● Power (105 hp original)
2. Acceleration
● Weight (2080 lbs original)● Gearing (5 spd manual)● Torque (electric will have more than stock!)● 0.5G off the line acceleration? We'll see...
Budget
● What's the maximum you're comfortable spending on this project? ($20,000 including the car)
● Donor cost vs. parts cost; is the vehicle worth spending a lot of money on? (Yes)
● Can you meet your range and performance expectations with your selected donor vehicle and budget? (We'll See!)
● Can you sell parts removed from the donor? (Yes)
● Could you share the project with a friend? (Possibly)
EV Components
● Motors – AC50
● Adapters and drivetrain – From CanEV, standard trans FWD
● Controller – Curtis 1238R
● Batteries – 36 x 100 Ah Sinopoly
● Battery Management System – Mini BMS
● Chargers – 1.5 kW Elcon
● Auxiliaries● DC-DC converter – 30 A● Vacuum Pump - yes● Power Steering – manual steering available● Heater – 3 kW min + add on heated seats!
Performance Estimation
● AC 50 Motor torque = 110 ft lbs from 0-4000 rpm
● 110 ft lbs x 12.5:1 gear ratio in 1st = 1375 ft lbs wheel torque
● 1375 ft lbs x 12”/11.5” tire radius = 1437 lbs thrust
● 2200 lb estimated car weight
● 1st gear = 0.65G up to 35 km/hr (4000 rpm)
● 2nd gear = 0.35G up to 65 km/hr (4000 rpm)
● Potential 2 sec to 50 km/hr!
● Zippy performance in the city: Check!
Range Estimation
● Pack Size = 36 x 100 Ah Sinopoly
● 115 V x 100 Ah = 11.5 kWh pack size
● City fuel economy = 6.7 L/100 km city
● 6.7 L/100 km x 9.63 kWh/L = 0.645 kWh/km
= Energy burned
● 0.645 Wh/km x 15% (city effciency) = 0.097 kWh/km
= Mechanical energy needed
● 0.097 kWh/km ÷ 80% (EV effciency) = 0.121 kWh/km
= Electrical energy needed
● 11.5 kWh ÷ 0.121 kWh/km = 95 km max city range ● 75 km safe city range, 60 km safe highway range
Cost Estimate
● AC 50 Motor / Curtis 1238R Controller
● $4,300● Motor Adapter
● $850● 36 x 100Ah Sinopoly Cells
● $5,000● Battery Management System
● $600● 1.5 kW Charger
● $400● Accessories (DC-DC, Vacuum Pump, Instrumentation, Wiring,
Metal work, etc.)
● $1,500● Total = $12,650, Typical used Echo - $5,000
● Check out my blog
● Links to useful EV websites ● This presentation in PDF format.
www.jessetufts.wordpress.com
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