G K t E i i P j tGo-Kart Engineering Project
fTeam of 13 students
Electric, Plug in, Go-Kart Project
Team deadline for completed project: March 31,2010
Obj tiObjectives
B ild l t i k t th t Build an electric go-kart that can plug right into a 120 V AC current outletoutletHave the ability to go 30 MphHave the vehicle safe to driveHave the vehicle safe to driveDesigned to fit a 6ft 6in 300 pound personpFundraise to earn $2,500 to aid in the completion of the go-kart
B tt i d h i tBatteries and charging systems
We are looking at48 volt batteries to reduce the current drawdraw.40-50 Ah capacity for approximately an hour or more battery life based off a 2 hour or more battery life based off a 2 horsepower motor.An approximated 3 hour charging time.
Battery Study for Different Storage Options
Closer study, comparing the lifecycle cost of Sealed Lead Acid Batteries and the lifecycle cost of LiFePO4Batteries, and the lifecycle cost of LiFePO4
B tt A l iBattery Analysis
We had narrowed down our choices to between Sealed Lead Acid and Lithium Iron BatteriesLithium Iron Batteries.Currently, the best battery option is the Sealed Lead Acid battery and the Sealed Lead Acid battery, and we are researching the various pricesprices.
M tMotors
Used calculators to get an estimated motor power requirement1 Hp=746 WThe values we used in the
l l i d bcalculators we estimated to be higher than the real life values.
Calculator Estimate of Power Requirements at 5-45 MPH
Source: http://ecomodder.com/forum/tool-aero-rolling-resistance.php?Weight=700&WeightUnits=lbs&CRR=.01&Cd=.30&FrontalArea=10&FrontalAreaUnits=ft^2&FuelWh=33557&IceEfficiency=.75&DrivetrainEfficiency=.95&ParasiticOverhead=0&rho=ciency .75&DrivetrainEfficiency .95&ParasiticOverhead 0&rho1.22&FromToStep=5-120-5
M t A l iMotor Analysis
fFrom that data we find a 2 HP Motor would be sufficient to maintain our speed at 30MPH speed at 30MPH We are currently contacting local companies to find a second opinion companies to find a second opinion on our motor need.Additional analysis was done using:Additional analysis was done using:http://buggies.builtforfun.co.uk/Calculator/analyse metric phpulator/analyse-metric.php
Additi l A l iAdditional Analysis
T d t i i d f To determine power required for acceleration we preformed our own calculations:
lFP
**
==
τωτ
radradrotationinftMi
NsinmphmkgamFs
4922112528030
5.284)15__300(894.*318* 2 =−==
π
NmtireradiusinmNsrad
rotationrad
rinrotation
ftin
Mift
HrMi
3.41)__7.5(145.*5.284
4.922*)(7.5**2
_1*12*5280*30
==
==
τ
ππ
ω
wattssradNmP 38164.92*3.41 ==
F d S iFrame and Suspension
fMaterials in consideration for the frame:
St i l St lStainless SteelStrong and durableResistant to wearResistant to wear
AluminumInexpensivepLightweight
Possible Suspension Ideas:Independent rear-suspension
S f tSafety
Will include:SeatbeltKill i hKill switch
Under consideration:llRoll cage
AirbagsSpeed limiterSpeed limiter
S I f tiSurvey Information
Population size: 36Ages 16-18Wanted some potential customer opinion to influence our designNeeded to know what was most important to customers.C t tti i l t i t t Cost cutting in least important areas
S I f ti C ti dSurvey Information Continued
Average height: 5ft 8in80% wanted go kart to be close to h d h lthe ground – 4 inch clearance
70% wanted brake and gas pedal l d don single side, as opposed to
separated.65% b li i i f i l 65% believes suspension is fairly important (7+ on a 10 point scale)