Early on in the month, the team designed and installed a buzzer system in the Datsun connected to the BMS that warns the driver when a cell drops below a specified voltage. This was part of the solution to the problem we faced in March at the Spring Thaw Event where the batteries overheated and reached almost unrecoverable low voltages. Since we lost a few batteries at the Spring Thaw Event, the team put 12 more batteries in the front of the Datsun, bringing the car’s voltage up to around 176 V, the highest it is allowed to be for competitions and the highest it’s ever been in any of our cars. During this time we also reshaped one of the bottom side panels on the Datsun that had gotten a little beat up in one of the autocross runs from last month. We also continued to charge the car in preparation for the Herald Miller Invitational.
In the middle of April, the team traveled to North Carolina to participate in the Herald Miller Invitational, a substitute event created in place of the EV Challenge. To read more about that, click this link: https://svgsev.wordpress.com/2016/04/16/the-herald-miller-invitational/.
Towards the end of April, the team charged the Datsun and worked on minor things while also planning events and meetings for the future. We plan on taking the Datsun to the Shenandoah Valley Governor’s School’s Award Picnic in May to show off our work to other students, parents, and members of the community.
March has been an exciting month for the electric vehicle team! The team took a trip down to NCCAR in North Carolina to participate in the Spring Thaw Event and also showcased the cars to the community at the Shenandoah Valley Governor’s School Open House. The article for the Spring Thaw Event can be seen here: https://svgsev.wordpress.com/2016/03/17/ev-spring-thaw-event-2016/ and the article for the SVGS Open House is available here: https://svgsev.wordpress.com/2016/03/27/ev-team-at-the-svgs-open-house/.
Aside from the big events that the team has been participating in, the team has been working on fixing the batteries in the Datsun after the overheating problem that was faced at NCCAR. The solution to this problem was to remove the cover that used to be over the main pack of batteries because it held in heat. We will also be checking the temperature more often during racing to determine if further action needs to be taken before problems becomes too serious.
After the Spring Thaw Event, the seat belt for the passenger seat in the Datsun had to be fixed because it came loose. It was an easy fix that only took one meeting to complete.
A main focus of the team has been collecting and analyzing data from the battery management system while the car is running. We have experimented with and decided on shut off values for current, voltage, and temperature to prevent drivers from running the batteries past dangerous points. In addition to creating these shut off points, team members installed a buzzer to warn the driver when the lowest cell drops below 1.5 volts.
The EV team headed to Garysburg, North Carolina this past weekend to participate in NCCAR’s Spring Thaw Event. The event was designed to be an opportunity for teams to get practice in events such as autocross and acceleration. Half the team left for the event around 6:30 PM Thursday night with the Datsun so that they could get to the track early the next morning. The rest of the team joined up at NCCAR around 4:30 on Friday. The Porsche did not join the team on this trip as it is still in the process of being converted from lead acid to lithium ion batteries.
On Friday, the team designed and set up an autocross course for all of the teams to practice on. The Datsun ran well, averaging times around a minute and twenty-five seconds on a relatively long course that included a slalom, chicago box, and 360. In the evening, the batteries started to weaken and when the team checked them they were reaching dangerous temperatures of around 130 degrees Fahrenheit and voltages on about 7 of them had dropped to 0, making them useless.
To handle this tense and upsetting situation, members of the team pulled an all-nighter, working on cooling the batteries, taking out the worn down packs, salvaging batteries, and wiring new packs in. The team also charged the main pack of batteries overnight so that the car could hopefully race again in the morning.
On Saturday, the team spent the morning finishing up the Datsun and getting it to run again. Overall, the voltage dropped from 144V to about 130V with the removal of 4 cells. The team continued to practice on the autocross course throughout the morning, stopping every couple of run throughs to check on how the batteries were holding up both in relation to charge and temperature. The team ended the event with a debriefing of how it went and what needs to be done in the future to prepare for the EV Challenge in April.
Overall, the weekend was a great experience for everyone on the team. Every body got a chance to drive, giving some new members the opportunity to drive the car for the first time. We also had a passenger seat which gave people the opportunity to ride along as the car dodged (and sometimes hit) cones. The team did a great job of keeping positive attitudes in times of stress and hardship when the discovery was made that the batteries had been damaged and was able to put all the things they’ve learned this year to work under a large amount of pressure. The team made connections with members of other teams, talked with people connected to NCCAR, and even got to see a solar powered car brought to the event by a college team.
The team will eagerly continue working on bettering their cars for the EV Challenge in Raleigh, North Carolina in April with hopes of bringing a powerful Datsun and a lithium ion-powered Porsche.
The past few weeks have not gotten summaries because they have all been pretty similar. We spent a lot of time charging batteries to prepare for the conversion of our Porsche and working on wiring and figuring out the Orion battery management system. However, this week was a rather exciting one as we finished charging all of the batteries and got the Datsun’s battery management system to work while charging the battery pack.
On Sunday, the team prepared to participate in the Staunton Christmas Parade by creating posters, a music playlist, and doing some final touches on the cars.
On Monday, the weather was gloomy (rainy and cold) so the team decided it would be best for the cars if we did not participate. There was not a very big crowd at the parade in the rain so we believe this was a good decision.
On Wednesday, the team met from 6-9 and worked on charging the Datsun while observing the battery management system’s data as it balanced the pack of batteries for even charging. This was a very exciting accomplishment as it was what we had been working towards for so long. We were able to charge up our batteries to about 3.3 V each and the overall pack voltage to around 150 V. We recorded the data from the BMS and hope to graph it soon to look for trends and patterns that could be helpful to us in the future.
On Thursday, the team met during part of governors school to plan out the upcoming month and set goals for what needs to get done in order to stay on track for the upcoming Spring competition in North Carolina.
On Saturday, the EV team participated in the Waynesboro Christmas Parade where we spread community awareness about us and the Shenandoah Valley Governors School. We were able to drive the Porsche all the way through the parade without any problems.
Another thing that happened recently was that the team was mentioned on the Shenandoah Valley Governor School’s website for attending the NEAT Ralley in North Carolina in October. To read more about that, check out this link: https://svgsstudentnews.wordpress.com/2015/12/01/svgs-month-in-review-october-november-2015-experiences-and-community/