Archive for the ‘Sponsorship’ Category

FSGP/ASC2014: We Have Withdrawn

Monday, July 21st, 2014

Saturday July 19th was CalSol’s first and last day participating in the Formula Sun Grand Prix 2014 at the Circuit of the Americas. CalSol successfully got Zephyr on the track on Saturday morning. We were able to get a few laps around the track but soon discovered an electrical problem that caused the car to turn itself off after exceeding speeds around 30mph. To provide some context, it was necessary for Zephyr to reliably drive with a speed upwards of 60mph in order for us to take Zephyr on public roads. On the Circuit of the Americas track, one of the very first hurdles was getting past a steep hill before going around the first corner. After a few laps around the track, Zephyr started to cut off its power while climbing the hill.

Zephyr at the starting line of FSGP

Zephyr at the starting line of FSGP

We discovered that the electrical current limit of one of our systems was set too low, thus triggering a safety feature to shut down the car.  This is an anomaly, as we have been able to take the car to speeds upwards of 50mph. We examined every connector, board, wire, and piece of software that we could get our hands on. We were at a constant hustle to get the car running on the track again—but each time it would stall after ten seconds of acceleration. Members frantically ran to and fro along the track with tools, computers, and debuggers.

This went on for six hours. Unfortunately, by the end of the day we had only completed five laps out of the required forty-eight. Though ASC can grant provisional qualification to teams that have a high potential, CalSol decided to withdraw from the race simply because racing a car with an unreliable electrical system on public highways posed a safety risk for the team.

We are very disappointed. We had come out to Texas to race to Minnesota and our FSGP/ASC2014 experience was cut short.

Without a doubt, forfeiting ASC2014 was one of the team’s lowest and the most humbling moments. We learned that the importance of extensive testing wasn’t just some rookie comment, but rather it was an absolute necessity for any team who wants to ensure a reliable vehicle. We experienced first-hand what it meant to push ourselves even when we thought we could not be pushed any further. And the most encouraging part is, we got to interact with the kind and intelligent solar car community who worked across team affiliations to get every car up and running.

In ASC 2012, CalSol reached a respectable 4th place finish on a simple but well-tested vehicle. After ASC 2012, CalSol went great lengths to build a solar vehicle with the most efficient aerodynamics and solar cells, lightest body and chassis, and the most advanced manufacturing techniques that the team had ever undertaken. Despite the measures taken to create the most advanced solar car, we fell short in producing a reliable vehicle.

Like every car, Zephyr succeeded in some aspects and failed in others.

Before packing up, there was one more thing we were able to do in order to help the solar car community. Polytechnique Montréal turned sharply on a tight corner on the track and snapped one of their car’s two Mitsuba motors. The team ingeniously found a way to power the car with a single motor in mere hours, and conditionally qualified for ASC2014. However, being short one motor without a spare was not a comfortable situation for the Montréal team. Since CalSol’s Zephyr uses the same equipment, we let Montréal borrow two Mitsuba motors for the race.

In 2003, CalSol had motor issues and ended up racing with University of Kentucky’s motor. This week we were able to pay that kindness forward. I like to call it solar car karma. Even though we will not be able to race, we are still honored to participate in such an amazing community. We hope that our competitors are able to reach their fullest potential.

CalSol and Montreal collaborating to provide Montreal functional motors for ASC2014

CalSol and Montreal collaborating to provide Montreal functional motors for ASC2014

Montreal's damaged motor

Montreal’s damaged motor

With a great deal of dedication, perseverance, and solar car karma, we are making great progress in solar car innovation. We are using this experience as a stepping-stone for accelerated progress with Zephyr. We’ve identified key issues with over-eager safety systems and are developing a better testing strategy. The best days of this car have yet to be seen, and we are excited to see where we go next.

Min Ju Lee

CalSol team lead

CalSol 2014 team photo

CalSol 2014 team photo


Thank you GM for providing us with two Yukons for the race! While Zephyr will not make the trip up to Minnesota, several team members will travel with other teams up north to get the ASC 2014 experience

Thank you GM for providing us with two Yukons for the race! While Zephyr will not make the trip up to Minnesota, several team members will travel with other teams up north to partake in the ASC 2014 racing experience.

Electrical Team Making Progress and Giving Thanks!

Tuesday, June 24th, 2014
The Hackerspace has been kept heavily utilized by CalSol lately!

The Hackerspace has been kept heavily utilized by CalSol lately!

The electrical team has been making good headway lately, with new, experienced, and alumni members all working to finish the assembly, testing, and troubleshooting of Zephyr’s electrical system.

The HCI (Human Control Interface) sub-systems are able to communicate among themselves over the CAN bus, which stands for Controller Area Network and allows for communication without a central computer. These sub-systems include the dashboard, accelerator and brake, steering wheel and side panel, and the two motor controller controller (which controls the motor controller, and is dubbed the MC^2). The controllers are working, and the motors are able to spin.

Regarding the solar cells, the solar array is coming together, with the team ready to finish placing the cells. The MPPT’s (Maximum Power Point Trackers, which keep the solar array at an optimal power output by manipulating on the I-V curve) are able to communicate over CAN as well.

Additionally, the two power hubs (which distribute power to the various electrical systems, which need to be kept on lines of separate voltages) are ready, and the BMS (Battery Management System) seems to be operational. All the electrical boards have been soldered, populated with components, and tested. The battery box has been built, and the fuses, connectors, and peripherals are being mounted.

The HCI system, including the LCD readout for the driver

The HCI system, including the LCD readout for the driver

The little nickel strip on the bottom of the module with the hole punched out is used to help measure voltage across the battery banks

The little nickel strip on the bottom of the module with the hole punched out is used to help measure voltage across the battery banks

Careful alignment of the solar array is required, since the indentations on the carbon fiber shell allow for little tolerance

Careful alignment of the solar array is required, since the indentations on the carbon fiber shell allow for little tolerance

We couldn’t have done this without the financial and technical support of our sponsors:

Advanced Circuits, for producing many of Zephyr’s PCB’s!

Bay Area Circuits, also for producing many of Zephyr’s PCB’s!

LEMO, for donating connectors!

Phoenix Contact, also for donating connectors!

Linear Technology, for giving LT boards and chips, providing monetary donations, as well as technical support and guidance!




Thanks for catching up with us, and see you soon!

Thank You SunPower!

Friday, June 13th, 2014

With the Formula Sun Grand Prix / American Solar Challenge 2014 approaching in just a month, CalSol is in the process of organizing a list of generous friends and company sponsors who made it possible for us to engineer Zephyr and to enter in the SunRayce. In particular, the team decided to give a shout-out to our top three sponsors for this race. This shout-out to SunPower is dear to me because it’s what got me so hooked onto the team and also what led me to become the engineer that I am today.

Team members preparing for solar cell caulking.

Team members preparing for solar cell caulking.


SunPower Corporation is based in San Jose, Calif, and is America’s premier high-efficiency silicon solar cell designer & manufacturer. Almost all competitive teams participating in the American Solar Challenge use SunPower cells because not only are they efficient, they are also incredibly reliable. CalSol has been using SunPower cells dating as early as the late 90s, but we had never established a connection with the company until 2013.

With CalSol encapsulating our own solar cells for the first time this build season, we needed a lot of help. We talked to awesome local and corporate companies such as D2 Solar and Dunmore– the kind engineers from D2 solar and Dunmore gave us many samples to test and generously donated their time to troubleshoot our problems. We learned a lot, but we were far from being able to produce perfectly encapsulated panels.

By half-luck and half-coincidence, I got in contact with SunPower’s senior manager in business development. She is also a Cal grad and was intrigued by our project– and from there, the solar team’s progress took off quickly. We received bare SunPower solar cells, as well as invaluable engineering support from SunPower engineers. It’s been more than a year since SunPower and CalSol has been working closely together– and for over a year, the CalSol members have had the privilege of learning about the solar industry first-hand with the leading solar company in the world. And more importantly, we’ve had so much fun doing engineering.


Chatting up with SunPower's CEO Tom Werner at 2013 All-Hands meeting

Chatting up with SunPower’s CEO Tom Werner at 2013 All-Hands meeting

Impulse, the team, and SunPower's executive officers at the Richmond, Calif. facility.

Impulse, the team, and SunPower’s executive officers at the Richmond, Calif. facility.


Solar cell encapsulation @ the San Jose HQ

Solar cell encapsulation @ the San Jose HQ

The team is recognizing SunPower as one of our top three sponsors for Zephyr / ASC 2014. SunPower has not only provided CalSol with generous in-kind donation, but perhaps more importantly, invaluable engineering and moral support to the team. We know that the people at SunPower are busy individuals, and we cannot thank you enough for taking your time to help us with everything solar-related for Zephyr!


DC/DC Converter – Thanks, Vicor!

Tuesday, June 10th, 2014

It’s been a while since our last blog update, but the intrepid CalSol crew has definitely been busy. Both Zephyr’s mechanical and electrical systems are nearing completion, and with all the work being put into making this our greatest vehicle yet, we’ve got plenty to report with new updates!

We would like to thank Vicor Corporation for their generous donation of the DC/DC converter and its appropriate mounting and connection accessories, as well as the assistance of their applications engineers in selecting the components! But first, what does a DC/DC converter do? (more…)

First Fiberglass Mold

Tuesday, November 19th, 2013

After many hours of working on our male plugs we are finally moving on to fiberglass mold construction. This week we were able to hammer out one of the fairings and it turned out GREAT!

fiberglass mold


Thanks to our new material sponsor, Aircraft Spruce and Specialty Co., we were able to acquire the fiberglass mat and mold making equipment required to build all the molds for Zephyr.





Thank you, NXP!

Wednesday, April 24th, 2013

We’re proud to welcome NXP as a new sponsor!

The brains of a solar car are essential. For our designs, we use a distributed network of a handful of microcontrollers. Each node in our network controls something different, such as managing the batteries, controlling the motor, or taking all the input from the driver. An important decision is choosing these brains, and we have reached out to NXP for their help. Last December, a few members of CalSol went down to NXP to show off Impulse and talk about our plans for the future. We received a very friendly welcome, and we are hopeful of a bright future with them.

Our own prototype and the LPCXpresso

Our own prototype connected to the LPCLink portion of the LPCXpresso

One of NXP’s interesting products is their LPCXpresso boards. These development boards include both a microcontroller for rapid prototyping and a built-in JTAG debugger, the LPC-Link. This debugger gives us significantly more power than we have had previously, allowing us to step through our running code and see the complete state of the microcontroller!

NXP has given us 40 LPCXpresso boards and has agreed to provide microcontrollers and other integrated circuits as needed. The development boards have allowed us to quickly get up to speed, and we are already making our own prototype boards using NXP’s MCU’s. You can see one of our first boards with an NXP chip (made by team member Devan Lai) in the picture to the right. We are planning on using NXP’s Cortex-M0 LPC11C14 for many systems in the car. These microcontrollers only take a few milliamps to run, an incredibly low amount for how much power they have! This, combined with their integrated support for the CAN communication protocol, makes them well suited for our applications. As well, the move to a modern 32-bit ARM architecture allows our code to be both smaller and more efficient.

All of these improvements are incremental steps towards making our best solar car yet. We’re hard at work doing everything we can to increase performance, decrease power consumption, and maximize efficiency.