EML4930: Senior Design 1

Electric Motorcycle Design

Deliverable 3: Product Specification and Project Plan

Due Date: February 9th 2010Date Submitted: February 9th 2010

Group MembersBroderick Epperson

Michael FranckMichael Grgas

Ryan Thor

Table of Contents

Introduction..............................................................................................3Product Specifications.............................................................................3Components.............................................................................................3Motor........................................................................................................3Battery Stack............................................................................................4Motor Controller......................................................................................6Charger.....................................................................................................6Cost Breakdown.......................................................................................7Conclusion...............................................................................................8

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I. IntroductionThe purpose of this project is to design and build a small electric motorcycle. Uponcompletion, the motorcycle must be able to travel for five miles on a single charge, aswell as recharge its batteries in less than eight hours. It must also reach a minimum topspeed of twenty-five miles per hour on level ground. The goal is to build a moreenvironmentally friendly version of the same internal combustion engine motorcycle forless than 1500 dollars.

II. Product SpecificationsIn order to meet the goals listed above, power consumption of the vehicle needed to bedetermined. From [1], the total tractive power for accelerating a vehicle from rest to somefinal velocity equation was used.

The equation takes into account the vehicle mass factor δ, which is estimated at 1.0425 [1].Mass of the motorcycle alone is approximately 75 kg, and rider weight is 80 kg.Combined, these make up total motorcycle weight Mv. An acceptable acceleration time(ta) of 10 seconds was chosen to reach the top speed. Final velocity (Vf) is 25 mph (11.17m/s), while initial velocity (Vb) is 0 mph. For motorcycles with properly inflated tires, thecoefficient of rolling resistance (fr) is approximately 0.0055. Air density (ra) is 1.2 kg/m3

for standard atmospheric conditions. The drag coefficient (Cd) for the motorcycle wasestimated at 0.95 [1]. Frontal area of the motorcycle (Af) was measured. A 6’1” tall rider,seated upright on the motorcycle displaces a frontal area of 0.445 m^2.

Tractive power was calculated to be 1.212 kW or 1.62 hp. After estimating for a 25% lossof efficiency from the battery stack, motor, driveline and control electronics; the finalnecessary tractive power was found to be 1.515 kW or 2.03 hp.

III. Components i. MotorSeveral motors were found that meet the power requirements listed above. A decisionmatrix was use to narrow motor selection to option one, a General Electric motor, modelnumber 5KCR49RN2042Y. An obvious winner, due to its superior power to weight ratio,competitive price, and compact packaging.

Ptδ Mv

2 taVf

2 Vb2⎛

⎝⎞⎠

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Mv g fr Vf15ρa Cd Af Vf

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Equation 1: Total Tractive Power

Pt 1.212 103 W

Pt 1.25 1.515 103 W

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Table 1: Available Electric Motors

Table 2: Normalized Weights of Motor Qualities

Table 3: Motor Decision Matrix

Model Power Weight Dimension Price OverallWeight

1 5 5 3 4 4.72 5 0 0 5 2.53 5 0 1 5 2.74 5 3 0 2 3.55 5 1 1 1 3.06 5 3 1 3 3.7

ii. Battery StackBattery selection is based on a number of factors including (in order of importance)voltage, current rating, cost, weight, and geometry. From theoretical calculations it wasdetermined that in order to meet the customers expectations, a battery of at least 48 voltsand 32 amp-hours will be required to provide the proper power and current to the motor.Due to budget limitations, lead acid batteries are the only realistic option for a powersource. Though heavy and bulky, they are capable of providing the performancenecessary to meet the objectives. Ideally, a smaller, more efficient power source such as

Manufacturer Model Hp MaxRPM

Voltage(V)

Current(A)

Wt.lbs

Price$

DimensionsL x W x H

1. GE 5KCR49RN2042Y 2 3450 115/130 34 183.38

11.1 x 4.88x7

2. Leeson 116512 2 3450 115-230 179 n.a.

3. WWEM WWE2-18-145T 2 1800 208-230/460 2.7 142 14.1x 7.5 x

n.a

4. Leeson 5KC48TN2169 2 3450 115/230 21.2-10.6 39 347.7

2 n/a

5. Leeson 5KCR49WN0270 2 1725 115/230 45 391.35

14.1x 7.5 xn.a.

6. Leeson 5BC58JBS6341 2 1750 208/230 5.8 39 269.99

14.1x 7.5 xn.a.

Criteria Power Weight Dimension Price RowTotal

NormalizedWeight

Power n.a. 1 1 1 3 0.5Weight 0 n.a. 1 1 2 0.3

Dimension 0 0 n.a. 1 1 0.2Price 0 0 0 n.a. 0 0.0

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nickel cadmium, nickel metal hydride, or lithium-ion batteries would have been selected,but the cost of doing so would have been well over budget. After narrowing the selectionto lead acid batteries with current ratings between 50 and 32 amp-hours, a nominal amp-hour rating was decided on. The decision was based on the amount of time that will berequired to charge the batteries as well as the total weight of the batteries. Explained inthe chargers section, a 6 amp 48 volt charger was selected. In order to charge a 51 amp-hour rated battery with a 6 amp charger would require 8.5 hours. Higher amp-hour ratedbatteries require more cells and are in turn bulkier and weigh substantially more. Toreduce charge time and decrease total weight, a 32 amp-hour rated battery was selectedyielding a charge time of 5.3 hours and weight of 104lbs. Because these bulky batterieshave to be mounted to a motorcycle frame with a limited capacity, the battery’s geometryshould also be taken into account. The battery configuration chosen consumes a netvolume of 266 cubic inches which is the least when compared with the other batteries. Abattery box will be designed to weatherproof the system. The configuration shall beplaced on the bike so as not to hinder the riders comfort while operating the vehicle.

Table 4: Available Battery Options

Table 5: Normalized Weights of Battery Qualities

Criteria Weight Amp-hours Voltage Dimensions Price Row

TotalNormalized

WeightWeight n.a. 0 0 1 1 2 0.2

Amp-hours 1 n.a. 0 1 1 3 0.3Voltage 1 1 n.a. 1 1 4 0.4

Dimensions 0 0 0 n.a. 0 0 0Price 0 0 0 1 n.a. 1 0.1

Supplier Product# Qty V A-Hr Dimensions Price/

UnitNet Wt(lbs.) Total Price

1. ABS212V34T4LT

4 12 34 7.76 x 5.16x 6.14 $96.85 116 $319.80

2. ABS2SLA-12V35

4 12 35 7.63 x 5.13x 6.5 $59.95 120 $239.80

3. ABS212V45T4LT

4 12 45 7.80 x 6.54x 6.73 $108.95 133.2 $435.80

4. Bty.Mart3

GEL-8G-22NF

4 12 51 9.375 x 5.5x 9.25 $122.95 160 $491.80

5. Bty.Mart3

GEL-8G-01

4 12 32 8.313 x 5.13x 7.25 $73.95 104 $295.80

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Table 6: Battery Decision Matrix

Model Weight Amp-hours Voltage Dimensions Price Row

TotalWeighted

Total

1 4 3 5 3 3 18 42 3 3 5 3 4 18 3.93 2 4 5 2 1 14 3.74 1 5 5 2 1 14 3.85 5 3 5 3 4 20 4.3

iii. Motor ControllerDue to the modest power requirements of the project, a small AC motor controller wasselected from Curtis Instruments; model number 1236-53, which operates between 36-48volts and 350 amps. The team is waiting to hear back from the manufacturer for a pricequote.

iv. Battery ChargerThe previous battery charger used to recharge the motorcycle proved to be insufficientand will not recharge the batteries within eight hours. It was a twelve volt, variableamperage charger and required each of the four batteries to be recharged individually.The team must acquire a forty-eight volt battery charger that can provide enough amps toachieve a quick and sufficient recharge. A lightweight charger will be ideal. Space islimited on the motorcycle; the charger will most likely be placed in a small area behindthe rider. Compared to the rest of the motor and battery stack, the weight of the chargerwas a low priority. Due to the limited budget, a compromise between power anddimensions was sought out. After careful consideration, the best possible choice for thebattery charger that meets all the client’s needs is the Soniel 48V, 6A constant currentcharger. The Soneil unit will take approximately 5.3 hours to recharge the batteries froma completely drained state. Draining the batteries to less than thirty percent of a fullcharge is not recommended as it can cause permanent damage. The only drawback of theSoneil battery charger is that it can only operate at constant current, which infers that thecurrent does not change during charging applications. While under these constraints thebatteries can not recharge faster than 5.3 hours.

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Table 7: Available Battery Chargers

Manufacturer ModelNumber Amps

ChargeTime(hrs)

Price$ Vendor Dimensions

(L x W x H)Weight

(lbs)

1. Soniel Son4808SRF 3.5 9.1 149 Batterystuf

f.com6.9" x 3.7" x

1.9" 1.7

2. Leneage INTLS485 5 6.4 169 Batterystuf

f.com6" x 6.5" x

5.25" 13

3. Soniel SON4812SR 6 5.3 159 Batterystuf

f.com8.5" x 4.25"

x 2.25" 2

4. SchauerJAC1548H0891-

11215 2.1 309 Batterystuf

f.com11.25" x 7.0"

x 6.375" 11

5. Dual Pro E4815 18 1.7 386 Batterystuff.com 8" x 7" x 8" 29

Table 8: Normalized Weights of Charger Qualities

Criteria Charge Time Dimensions Price Weight RowTotal

NormalizedWeights

ChargeTime n.a. 1 1 1 3 0.5

Dimensions 0 n.a. 1 1 2 0.333Price 0 0 n.a. 1 1 0.167

Weight 0 0 0 n.a. 0 0

Table 9: Battery Charger Decision Matrix

Models ChargeTime Price Dimensions Weight Overall

Weight1 1 5 4 5 2.6672 2 3 3 3 2.5013 3 4 5 4 3.8334 5 1 1 2 3.0005 5 1 1 1 3.000

Cost BreakdownItem Quantity Total Cost

Batteries 4 295.80Motor 1 183.38

Charger 1 159.00Controller 1 *

Total: 638.18*Awaiting price quote from manufacturer

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ConclusionAfter weighing the available options, and selecting the best components for the specifiedcustomer’s needs, the team is pleased with the initial cost structure and is well belowbudget. This document is pending review by the team’s technical advisor, Bruce Thigpen.

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AppendixFrontal Area of Motorcycle (Af):

Tractive power equation for 25 mph:

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Tractive power equation for 15 mph:

δ 1.0425ρa 1.2

kg

m3

Mv 155kg

ta 10sCd 0.95

Vf 11.17ms

Af 0.445m2

Vb 0ms

g 9.807

m

s2

fr 0.0055

Ptδ Mv

2 taVf

2 Vb2

⎛⎝

⎞⎠

23

Mv g fr Vf15ρa Cd Af Vf

3

Pt 1.212 103 W

Pt 1.25 1.515 103 W

Vf2 6.7ms

Pt2δ Mv

2 taVf2

2 Vb2

⎛⎝

⎞⎠

23

Mv g fr Vf215ρa Cd Af Vf2

3

Pt2 430.541W

Pt2 1.25 538.176W

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Works Cited

1. Ehsani, Mehrdad, Yimin Gao, Sebastien E. Gay, Ali Emadi. Modern Electric, HybridElectric, and Fuel Cell Vehicles. Boca Raton: CRC Press, 2005

2. BatteryMart.com. 8 February 2010 <http://www.batterymart.com/>.

3. Advanced Battery Systems, LLC. 8 February 2010<http://www.advancedbattery.com/>

4. Emotors Online.8 February 2010<http://www.e-motorsonline.com>

5. Electric motor superstore 8 February 2010<www.emotorstore.com/>

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