Fall 2012

Kyle Zampaglione, Darshan Kasar, Matt Roeschke

Berkeley Engineering and Sustainability Technology Labs

Advisors: Prof Alice Agogino, Prof George Anwar

Human Powered Gym: Pedal Powered Charging Station

Zampaglione Pedal Powered Charging Station 12/15/2012

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Abstract The pedal powered charging station is a continuation of work done over the summer of 2012. While the result from summer was flawlessly functioning, many aspects were lacking aesthetically. The Fall 2012 semester’s goal was to turn the pedal powered charging station into a finished product, ready for education in the Recreational Sports Facility. After several attempts at improving the current system, a finalized version was created for implementation in the RSF. The finished system charges older generation Apple products and lights LEDs to display varying power input. Final Product The final product builds on the design from the summer of 2012. The charging system has had little modification done to it. All wires have been replaced and cleaned up in appearance and quality of connections. A major addition to the bike is the LED display system. The LED display system consists of rows of LEDs along the bottom edges of the drive unit and up the length of the handlebar pillar. The LEDs serve as visual feedback to the user of how much power he or she is generating. As the user pedals faster, the LEDs brighten. This simple system shows to the user real-time results of their working out and bathes the exercise machine in a bright blue aurora. The LED lighting system operates on a similar system to the charging system. The major difference between these systems is the lack of battery in the LED system. The Xantrex C-35 in the charging system requires a battery to start the DC/DC conversion process. The LED system uses a much smaller Orion 24/12-5 DC/DC converter. See Appendix 1 for spec sheet on these components.

Figure 1: Orion 24/12-5 Source: http://www.neosolar.sk

The advantage of the Orion is that it does not need a battery to turn on its circuitry. The Orion will power on from the input voltage. For the bike, this means that pedaling will directly turn on the DC/DC converter and variably light the LEDs with whatever voltage is being put through. The lights will vary in brightness until the system reaches 12V; the output voltage of the Orion. After sufficient testing of the bike, it was concluded that the maximum producible voltage was 32V, just short of the 35V maximum of the Orion. A property specific to this model of Orion is no undervoltage shutdown. This means that from 0-14V, the converter will act as an open circuit and let the electricity flow through instead of store it until the voltage reaches an appropriate range.

The educational purpose of the LEDs is simply a visual representation. The charging aspect of the bike is the functional side of this prototype. While few changes were made to the charging system since the summer, the modifications made were important to the overall system. A switch was added to allow the user to turn the charging system on and off. With the switch off, the user can simply observe the LEDs variable brightness. When the switch is turned on, the battery connection to the Xantrex is completed. The user can now charge his or her phone from the Apple charging attachment. While the user charges his or her phone, the LEDs still maintain their variable brightness. The switch is important because it prevents the Xantrex from pulling charge from the battery while the bike is not in use.

To finish the bike aesthetically, the casing was modified. The right side of the case had to be cut away to allow the motor to protrude. Holes were drilled in the sides of the plastic casing to allow for axles to protrude. Clear polycarbonate was purchased to cover the rest of the electrical components below the reach of the case. The clear polycarbonate allows onlookers to see the componentry and LEDs. The motor was also given a clear polycarbonate case. After these modifications, the case bolted back together using its original mounts. Electrical Notes **Important**: due to lack of wires, black is positive and brown is negative. This convention is consistent for most connections.

Zampaglione Pedal Powered Charging Station 12/15/2012

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**Important**: The color of the wires coming directly from the motor (black and red) should be ignored. Due to the reversal of polarity from running the motor as a generator, the wires are reversed. This was confused several times in the construction process with the placement of the diode. It is best to ignore the color of these wires and start with the color convention of black as positive and brown as negative. **Important**: Since the Xantrex was wired previously, the wires coming directly from it were left the same. The white wires are positive and the black are negative on the output of the Xantrex. At the parallel junction at the end of each of these wires, the coloring goes back to the correct black and brown. The only black negative wire in this system runs from the Xantrex to the parallel junction of the battery and charger, and from that parallel junction to the charger. Likewise, the only white positive wires run from the Xantrex to the parallel junction of the charger and battery, and from the parallel junction to the charger. For a schematic of this system see Appendix 2. Physical Feedback Problems The team made several attempts at creating a physical feedback system. This physical feedback system aimed to increase resistance to the user as he or she attempted to power larger devices. For example, to power 4 60watts, the user would have to output 240watts. This would require a reasonable amount of effort from the user. Unfortunately it was found that creating a high resistance and a high power output power system was nearly impossible to do simultaneously. The reason for this is due to the properties of the back EMF that generates the voltage in this system. When a DC electric motor is driven by an external force, it creates a back voltage (back EMF). This voltage is caused by induction and varies with speed. This is what makes DC motors viable generators for systems that can turn them near their operating speed. The bike can easily turn the motor at the required 2400rpm necessary to create 24V. Normally with electronic devices, the power drawn increases with the amount of load. For the bike system, the goal was to increase feedback to the user as load increased. This would represent the larger amount

of power required for larger loads while maintaining the same pedaling cadence. As more load was added to the system, it was found that exactly the opposite happened; the bike became easier to pedal. Though the system did require more power to satisfy the load, the input was becoming easier to spin. This phenomenon is caused by the inductance of the motor creating power in the opposite direction. The braking power can be modeled by P= I2R where I is the current returned to the motor and R is the internal resistance of the motor. From this model it is easy to see that when shorting the motor, the maximum amount of current can flow back into the windings, creating a huge stopping force, or in the bike’s case, resistance to the user. The implemented system demonstrated this braking power, just not in the intended way. As more load was added to the system, less current would flow back to the motor, thus creating less braking power. An easy way to think about this is that as more load is added to the system, the leads of the motor move towards an open circuit. An open circuit is easy to visualize because when nothing is attached to a DC motor, it spins relatively freely. Through experimentation it was found that even small amounts of resistance would cause the motor to still feel like an open circuit. A potential reason for this was actually having too nice a motor. DC motors are designed to have small, almost negligible internal resistances. Referring back to the braking power formula, a current that is nearly infinite is needed to oppose a resistance that is nearly zero. Any load will cause this current to rapidly drop from infinity. For this reason, it was extremely difficult to feel considerable resistance at the user input with any load across the motor. After many tries it was deemed unfruitful to continue to develop a system that could create both high power output and high resistance and be integrated into the current work. Outside parties who have made similar bikes that did give accurate feedback were contacted and it was found that they used simulated feedback systems for education purposes. Future Considerations One very important future consideration would be to use an actual generator for the system. Currently the system uses a DC motor. The difference between DC motors and generators is the number of windings.

Zampaglione Pedal Powered Charging Station 12/15/2012

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Generators have far more windings which allows them to generate more power on each turn. This would hopefully mean that the generator has a greater internal resistance, which would create more resistance for the user. A common generator that could be tested for this project is a car alternator. A car alternator is an AC generator with built in inverter that outputs 12V DC. Car alternators range from 45-120A of output current; meaning they produce well over 1000watts of power when connected to an appropriate load. A car alternator was purchased for the project but it has not been tested due to complications with starting. Alternators require a nominal starting current to create the initial inductance in the coils. After the alternator has started turning, the input current can be shut off. No system has been made yet to create this current. Fixtures will also be needed to implement the alternator in the current system. Another future consideration is to switch the Apple charger for a standard 12V to USB charger. These have also been purchased for the project but have not been rewired for the system. This is a simple change and will mean that any user with a USB charge capable device can use the bike for power. One last future consideration is to switch the belt configuration for chains. The system was originally changed to belts because of concern that the motor could not be spun fast enough to generate the required voltage. Belts allowed much higher ratios between pulleys. Now that the entire system only requires between 12-20V powering both the Xantrex and Orion, it would be safe to switch back to the lower ratios of chains. Some advantages of chains drive are that the lengths of chains are adjustable and they can be run slightly out of line. The belt system is a hassle because each pulley must be perfectly aligned or else the belt will slip off. Conclusion Overall, this semester saw positive progress on the bike. Though much of the time was spent trying to develop a feedback system for the user that ultimately failed, the knowledge gained will be useful for future developers. The bike is fully functioning and ready for use in an educational setting. The changes detailed in the previous section would simply improve on the design. The project has ultimately achieved what it set out to do: charge simple electronic devices and educate

users about energy usage through visual and physical means. Acknowledgements

The Pedal Powered Charging Station would like to thank the staff in the ME machine shop in Etcherverry and Hesse for their continued help with fabricating parts. The team would also like to thank Tom Clark for his electrical input and giving us access to wires and other electrical necessities. Finally the team would like to thank Professor Agogino and Professor Anwar for their continued support and interest in this project.

Xantrex Technology Inc.Headquarters

8999 Nelson Way

Burnaby, British Columbia

Canada V5A 4B5

800 670 0707 Toll Free

604 420 1591 Fax

5916 195th Street NE

Arlington, Washington

USA 98223

360 435 8826 Telephone

360 435 2229 Fax

www.xantrex.com© 2003 Xantrex Technology Inc. All rights reserved. Xantrex is a trademark of Xantrex International. P/N 970-0026-01-03 Rev C Printed in Canada

C Series Controllers

Charge, Diversion, or Load Controllers

A charge controller is an important system component that regulates the voltage generated from your renewable energy system and properly maintains your batteries. It protects your batteries from being over and under charged, and ensures maximum battery life. Considered to be the best in the industry, Xantrex Charge Controllers offer a variety of features. The C Series offers three models, the C35, C40, and C60, designed for 35, 40, and 60 amps of DC current.

FeaturesSilent, pulse width modulated (PWM), high efficiency operation.

Three-stage battery charging (bulk, absorption, and float) with optional temperature compensation.

Automatic overload protection in both active and passive modes. PV array short circuit and reverse polarity protection. Durable construction. Microprocessor controlled.

As a Solar Charge ControllerWhen used as a solar charge controller, the C40 can control 12, 24, or 48 VDC array operation and the C35 and C60 can control 12 and 24 VDC array operation.

All units offer selectable settings for NiCad, flooded lead acid, gel, or absorbed glass mat batteries.

As a DC Load ControllerAs a DC load controller, the C Series has a low voltage disconnect warning indicator and field adjustable set points that govern automatic low and high voltage disconnect.

Manual reset switch for emergency low voltage operation.

As a Diversion ControllerThe C Series automatically directs extra power to a dedicated load, such as an electric water heater, and ensures batteries are never over-charged.

OptionsPlug-in remote temperature sensor (BTS) for increased charging precision.

Cumulative amp-hour meter (CM) that can be installed on the face of the controller, or remotely (CM/R), up to 100 feet (30 m) away.

C40 & C60 C35 CM

Specifications subject to change without notice.

Model C35 C40 C60

Voltage Configurations 12 and 24 VDC 12, 24, and 48 VDC 12 and 24 VDC

Max. PV Open Circuit Array Voltage 55 VDC 125 VDC 55 VDC

Charging / Load Current (@ 25 °C) 35 amps DC 40 amps DC 60 amps DC

Max. Peak Current 85 amps 85 amps 85 amps

Max. Voltage Drop Through Controller 0.30 volts 0.30 volts 0.30 volts

Typical Operating Consumption 15 ma 15 ma 15 ma

Typical Idle Consumption 3 ma 3 ma 3 ma

Recommended Breaker Size 45 amps 50 amps 60 amps rated at 100% continuous duty

Recommended Wire Size #8 AWG #8 AWG #6 AWG rated at 90 °C

Lead Acid Battery Settings Adjustable Adjustable Adjustable

NiCad Battery Settings Adjustable Adjustable Adjustable

Load Control Mode Low Voltage Reconnect - Adjustable (sticker provided with unit) all models

Low Voltage Disconnect - User selectable manual or automatic reconnection - includes warning flash before disconnect

and provides a one time, user selected grace period) all models

C Series Controllers

Charge, Diversion, or Load Controllers

Electrical Specifi cations

General Specifi cations

Specified Temperature Range 32 °F to 104 °F (0 °C to 40 °C)

Enclosure Type Indoor, ventilated, powder coated steel with 3/4” and 1” knockouts

Unit Weight 2.5 lb (1.2 kg) 3.0 lb (1.4 kg) 3.0 lb (1.4 kg)

Shipping 3.0 lb (1.4 kg) 3.5 lb (1.6 kg) 3.5 lb (1.6 kg)

Dimensions (H x W x D) 8.0” x 5.0” x 2.5” 10” x 5” x 2.5” 10” x 5” x 2.5”

20.3 cm x 12.7 cm x 6.4 cm 25.4 cm x 12.7 cm x 6.35 cm (25.4 cm x 12.7 cm x 6.35 cm)

Shipping Dimensions (H x W x D) 12.4” x 7“ x 2.5” 12.4” x 7“ x 2.5” 12.4” x 7“ x 2.5”

31.5 cm x 17.8 cm x 6.4 cm 31.5 cm x 17.8 cm x 6.4 cm 31.5 cm x 17.8 cm x 6.4 cm

Mounting Vertical wall mount - indoor only

Altitude - Operating 15,000’ (4,572 m)

Altitude - Non-Operating 50,000’ (15,240 m)

Warranty 2 years

Part numbers C35, C40, C60 - Controllers

CM - Front Display Panel

CM/R-50, CM/R-100 - Remote Display Panel

BTS - Battery temperature sensor

Features & Options

Regulation Method Solid state, three-stage (bulk, absorption, and float), pulse width modulation

Field Adjustable Control Setpoints Two user adjustable voltage setpoints for control of loads or charging sources - settings retained if battery is disconnected

Display Panel CM, CM/R-50, or CM/R-100 - optional LCD - backlit, alphanumeric display showing battery voltage, DC amperage,

cumulative amp hours, and amp hours since last reset - remote includes 50’ (15 m) or 100’ (30.5 m) cable

Equalization Charge User selectable manual or automatic equalization - every 30 days

Battery Temperature Sensor BTS - optional remote battery temperature sensor for increased charging precision

Regulatory Approvals

UL Listed to UL 1741 - 1999 and to CSA 22.2 No. 107.1-95 Standards, CE compliant

www.victronenergy.com

Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | Fax: +31 (0)36 535 97 40 E-mail: sales@victronenergy.com | www.victronenergy.com

Orion 24/12-25 Orion 24/12-40 Orion 24/12-70

NEW Non isolated converters

Orion 24/12-5

Orion 24/12-12

Orion 24/12-17

Orion 24/12-25

Orion 24/12-40

Orion 24/12-70

Orion 12/24-8

Orion 12/24-10

Orion 12/24-20

Input voltage range (V) 18-35 18-35 18-35 18-35 18-35 18-35 9-18 9-18 9-18

Undervoltage shutdown (V) - 14 14 14 14 14 8 8 8

Undervoltage restart (V) - 18 18 18 18 18 10 10 10

Output voltage adjustable with potentiometer

no no no yes no yes no yes yes

Output voltage (V) 12 12 12 Adjustable 10–15V F set 13,2V

12 Adjustable 10–15V F set 13,2V

24 Adjustable 20-30V F set 26,4V

Adjustable 20-30V F set 26,4V

Efficiency (%) 92 95 94 96 95 92 95 95 93

Suitable to buffer-charge a battery no no no yes no yes no yes yes

Can be connected in parallel no no no yes no yes no yes yes

Continuous output current (A) 5 12 17 25 40 70 8 10 20

Max. Output current (A) 5 20 25 35 55 85 20 20 30

Fan assisted cooling (temp. controlled) no no no no yes yes no no yes

Galvanic isolation no no no no no no no no no

Off load current < 5mA < 7mA < 7mA < 15mA < 20mA < 20mA < 10mA < 15mA < 30mA

Remote on-off no no no yes yes yes no no yes

Operating temperature range

(derate 3% per °C above 40°C) -20 to +55°C -20 to +55°C -20 to +55°C -20 to +55°C -20 to +55°C -20 to +55°C -20 to +55°C -20 to +55°C -20 to +55°C

DC connection Faston tabs 6.3 mm

Faston tabs 6.3 mm

Faston tabs 6.3 mm

Faston tabs 6.3 mm

Double Faston tabs 6.3 mm

M6 bolts Faston tabs 6.3 mm

Faston tabs 6.3 mm M6 bolts

Weight kg (lbs)

0,2 (0.40)

0,3 (0.65)

0,3 (0.65)

0,7 (1.55)

0,85 (1.9)

0,9 (2.0)

0,4 (0.8)

0,4 (0.9)

0,9 (2.0)

Dimensions hxwxd in mm (hxwxd in inches)

45x90x65 (1.8x3.5x2.6)

45x90x100 (1.8x3.5x3.9)

45x90x110 (1.8x3.5x3.9)

65x88x160 (2.6x3.5x6.3)

65x88x185 (2.6x3.5x7.3)

65x88x195 (2.6x3.5x7.7)

45x90x115 (1.8x3.5x4.5)

45x90x125 (1.8x3.5x4,5)

65x88x195 (2.6x3.5x7.7)

Remote on-off connector on the high power models (see table below)

The remote on-off eliminates the need for a high current switch in the input wiring. The remote on-off can be operated with a low power switch or by the engine run/stop switch (see manual).

All models with adjustable output can also be used as a battery charger

For example to charge a 12 Volt starter or accessory battery in an otherwise 24 V system.

All models with adjustable output can be paralleled to increase output current

Up to five units can be connected in parallel.

The Orion 12/27,6-12: a 24 V battery charger (see page 2)

To charge a 24 V battery from a 12 V system. The output voltage of this model can be adjusted with a potentiometer

A super wide input range buck-boost regulator: the Orion 7-35/12-3 (see page 2)

The Orion 7-35/12-3 is an isolated converter with a very wide input range, suitable for both 12 V and 24 V systems, and a fixed 12,6 V output.

Easy to install

Delivery includes four Insulated Fastons Female Crimp 6.3 mm (eight Fastons in case of the Orion 24/12-40).

Notes: - Other in- or output voltages at request - All natural convection cooled models can also be modified to IP65

Orion DC/DC Converters

Orion 24/12-5

Orion 24/12-17

Victron Energy B.V. | De Paal 35 | 1351 JG Almere | The Netherlands General phone: +31 (0)36 535 97 00 | Fax: +31 (0)36 535 97 40 E-mail: sales@victronenergy.com | www.victronenergy.com

Orion isolated 100W Orion isolated 360W

Isolated converters Orion xx/yy-100W Orion xx/yy-200W Orion xx/yy-360W

Power rating (W) 100

(12,5V/8A or 24V/4A) 200

(12,5V/16A or 24V/8A) 360

(12,5V/30A or 24V/15A)

Galvanic isolation yes yes yes

Temperature increase after 30 minutes at

full load (°C) 25 30 30

Fan assisted cooling (temp. controlled)

no yes yes

Weight kg (lbs) 0,5 (1.1) 0,6 (1.3) 1,4 (3.1)

Dimensions hxwxd in mm (hxwxd in inches)

49 x 88 x 152 (1.9 x 3.5 x 6.0)

49 x 88 x 182 (1.9 x 3.5 x 7.2)

64 x 163 x 160 (2.5 x 6.4 x 6.3)

Input voltage (xx): 12 V (9 – 18 V) or 24 V (20 – 35 V) or 48 V (30 – 60 V) or 96 V (60 – 120 V) or 110V (60 – 140V)

Output voltage (yy): 12,5 V, 24 V or 48V

Isolated 24V battery charger: Orion 12/27,6-12

Input 9 – 18 V, output 27,6 V, current limit 12 A, fan assisted cooling Output voltage adjustable with potentiometer Weight 1,4 kg (3.1 lbs), dimensions 64 x 163 x 160 mm (2.5 x 6.4 x 6.3 inch)

Isolated buck-boost regulator: Orion 7-35/12-3

Input 7 – 35 V, output 12,6 V current limit 3 A, derate current linearly from 3 A at 18 V to 1,5 A at 7 V Weight 1,4 kg (3.1 lbs), dimensions 64 x 163 x 160 mm (2.5 x 6.4 x 6.3 inch)

Common Characteristics

Output voltage stability 2 % (Orion 12/24-7 and Orion 12/24-10: + 0% / - 5%)

Output voltage tolerance 3 %

Output noise < 50 mV rms

Off load current < 25 mA (isolated converters)

Efficiency Non isolated: appr. 92% Isolated: appr. 85%

Isolation > 400 Vrms between input, output and case (isolated products only)

Operating temperature - 20 to + 30°C (0 to 90°F). Derate linearly to 0 A at 70°C (160°F)

Humidity Max 95% non condensing

Casework Anodised aluminum

Connections 6.3 mm (2.5 inch) push-on flat blade connectors

Protection: Overcurrent Overheating Reverse polarity conn. Overvoltage

Short circuit proof Reduction of output voltage Fuse and reverse connected diode across input Varistor (also protects against load dump)

Standards: Emission Immunity Automotive Directive

EN 50081-1 EN 50082-1 95/45/EC

1N3211

MotorOrion 24/12-5

In+

In-

Out+

Out-

LED Strips +

LED Strips -Xantrex C35

In+

In-

Out+

Out-

PowerSonic Battery

12 V

ChargerInput +

Input - Output

To Ipod Charger

Switch