Wednesday, February 22, 2017

Week 3

Design:
With the design approval, calculations of required amount of materials were established. The quantities of aluminum stock was communicated with the track team. Currently, waiting for a response to determine if more material needs to be purchased from Coastal Aluminum. Confirmed with the track improvement team that the ribs will need to be fabricated according to previously mentioned specifications. Measurement of charging components and supporting hinged box were made to create a Solidwork design. The solar rack design still needs minor improvements to the mating of the two separate pieces before completion.

Procurement/Fabrication:
Position locking draw slider was purchased to match the physical dimensions of the solar rack and charging components. I am hoping to have all designs finalized by the first presentation. With that part complete, fabrication of components can begin that weekend.

T-bar:
A new idea of the modifying the supports proposed to the track team. An additional clamping plate between the T-bar and the 3-bar linkage can shift of the weight of the rack further in towards the center or outer perimeter of track loop to help with any stability issues.

Wednesday, February 15, 2017

Week 2

Derick:

Over the weekend, I was able to charge a battery to its maximum capacity. The maximum voltage was 8.60 V. Voltage peaked and any additional further charging did not provide a noticeable voltage increase. The same problem occurred when sunlight was blocked or interrupted for a short duration. The problem was identified to be the charger and its lack of a self-resetting algorithm. Other compatible chargers with a function to reset itself can used to remedy this problem. With a short deadline, this issue will be low priority.

Further design with the racking system incorporated the two T-bar pole mounts. Modifications were made to the rack that includes attachment points to the two T-bar mounts. The four existing T-bar for the pair of solar racks will require adjustment slots in order to compensate for the play made possible from the swaying of the poles or uneven pavement surface. The attachment points on the solar rack lack the dimensions necessary to compensate for the play, therefore the four T-bars was determined to be modified.

A design for a box to store the charging components was created. The basis of this design is to be able to slide a folding box from underneath the charging rack and provide access to the components regardless of the tilt rotation of the solar rack. The tilt rotation of the solar rack is fixed when placed on to the two support poles. With the solar rack removed and spun around in 180 degrees, the rack will be able to tilt in the opposite rotation. The design will provide easy accessible to the components regardless of the orientation of the tilt of the solar rack.

Tuesday, February 7, 2017

Battery Charging

Derick:

This week consisted of me testing the charging operations of the components. The goals of this week were to determine functionality and approximate charging time. The charging components are operational and able to charging a battery from 7.56 V to 8.10 V. Without any references, the state of charge of the battery via voltage readings could not be determined. Time was also immeasurable due to charger resets when input voltage was not within range. Testing of the components will continue next week with a recording device and longer duration in order to determine the maximum voltage.

Parts of the solar rack were dimension-ed and drawn in SolidWorks. After further thought, the solar rack will be redesigned as a single part instead an assembly.


Solar racking rib


Aluminum bar to form rectangular base


Alan:

As stated above, this week was focus on making sure all the components work properly, that they are wired correctly, and testing the whole circuit in the sunlight. Both solar panels will be utilized because we need them to charge one battery pack each. I communicated with the Controls team to make sure which battery packs they will use and they decided to use the 4AA pack.

Two solar are going to be used because charging multiple batteries with one solar panel would not work well. It is possible to connect batteries in parallel in order for one solar panel to charge multiple battery packs but the issue with this is that all the batteries need to have the same voltage, otherwise the battery pack with highest voltage will discharge into the lower voltage one. This is not ideal because the battery packs will not always have the same voltage.