Guide to the 2023 FSAE Cost Module Changes
It is very unwise for teams to roll over the Electrical and Drivetrain sections of their cost report from 2022, even if nothing has changed between vehicles. Sweeping changes to these sections of the report means a lot of rework on the team’s end and a high risk of error. Take the time to start from scratch with these sections and learn how to Cost them correctly.
Prerequisites: did you read these?
FSAE Cost Supplement V3
Cost Module Operations PPT
FSAE Rules
All these items can be found on the Document Resources on FSAEOnline.
A Short History Lesson of the Electrical Cost Modules
In 2009, the new cost model was introduced. EV cost modules were published in 2011 to complement the new EV class. Standardized, parameterized materials and processes were established with fixed costs to simplify the electric vehicle costing process. The general process was to cost a “Chassis Control Module”, which is generally an electronic module designed to perform various functions of vehicle control. Additionally, the process was to include add-ons such as +Housing, +IMD, +Battery Charger, etc. as required by the vehicle configuration and Chassis Control Module type.
You can read the long form description from our friends at FSA below:
https://fsaustria.at/wp-content/uploads/17/FSA-Cost-Appendix_v1.pdf
These modules have served the series well for the last 12ish years, but as teams continue to electrify their vehicles (regardless of vehicle class), combined with the growing popularity of creating custom printed circuit boards (PCBs) for the vehicles, we see a gap in the online cost catalog for capturing these costs adequately.
We analyzed cost reports submitted for 2022 and surveyed teams regarding their various electrical modules and found a couple of things:
Most EV teams are using custom boards/microcontrollers for TSAL, BMS, ECU, and PDM
Nearly every PDM solution was custom
Only about 30% of teams are using off the shelf BMS
The Electrical Cost reports varied wildly across teams with similar systems, showing a disconnect in understanding of how to use the standardized cost modules and/or a disconnect between the cost module items and the actual system being evaluated (six versus one half dozen, in my opinion)
If the Cost Modules are confusing and not representative of the vehicles, the students lose the benefits that the Cost Event provides. So, we are looking to clarify how the catalogs are used and change our approach in electronics costing to better capture these vehicle costs. Remember, “The Cost and Manufacturing Event evaluates the ability of the team to consider budget and incorporate production considerations for production and efficiency.” If we cannot allow for choice (commercial-off-the-shelf (COTS) vs custom electronics) of what can be the most expensive section of the cost report, we cannot illustrate the considerations for production and efficiency for the mass production vehicle.
A New Approach
Understanding cost impacts of Chassis Control Modules (CCM) and making design decisions to reduce their cost is a valuable skill that the students can learn by performing a deeper dive into these module costs. While we recognize the ease of use of the standardized costs for CCMs, in some cases the students can benefit from a “long form” costing of custom PCBs. Furthermore, we recognize that the selection of various modules such as Battery Management Systems and Engine Control Units are not always cost driven as teams source these modules through sponsorship or as carryover components.
The new approach does not intend to punish teams for using custom PCBs (by adding extra work) versus sourcing COTS (by adding cost) which provide equivalent functionality. The costs derived in this new method were tested and compared to previous methods, and we found that custom solutions with equivalent functionality were generally on par with COTS components in the online cost catalog. Obviously if a team sources a COTS BMS and only uses half the functionality, it’s logical to assume the BMS would cost more than a custom solution stripped of the extra functions.
We anticipate this may widen the Cost gap between the high-budget, high-tech cars and those which are using less electronics. This is similar to the difference between space frame vs monocoque, and aero vs no aero. This will likely reduce the cost of EVs with minimal auxiliary sensor boards and student-designed modules. The impacts will be lesser in the IC class, but still present for teams using BSPD, custom dashboards, etc.
This new approach adds a section to the Catalogs for PCB costing, and adds the following Materials:
Circuit Card Assembly
Perforated Circuit Board
Complex Integrated Circuit
Simple PCB component
Connector, Wire to Board
Conformal Coating
Development Board
PCB Stencil (this is in the Tooling Catalog)
. Applicable processes for the PCBs are as follows:
Circuit Card Assembly Labor
Solder Paste Apply
Conformal Coat Apply
Details on what these materials and processes are and when they are used can be found in the Cost Supplement and the online Cost Catalog. There are several options for a couple of these items and it’s wise to read the Cost Supplement prior to starting your PCB costing.
Students should be aware that the PCB is not the only piece of the puzzle – we have deleted the “Chassis Control Module – Housing” item, which means that the housings for the PCB (if present) should also be costed using existing Catalog Processes and Materials. Assembly processes, Fasteners, etc., have not changed. As usual, we expect to see Materials and Processes for assembling the module to your harness and the car.
When Should I use the PCB catalog?
We’ve created a workflow that appears in V3 of the Cost Supplement for deciding how to cost your electronic module. Most electronic modules are still cost as bought. For your convenience, here’s a short form of the decisions:
On Board Charger, Motor Controller, IMD, still cost as bought
BMS, Dashboard Screen, Datalogger, and ECU may be cost as bought or made, depending on whether it is a COTS item or custom. See workflow
BSPD, TSAL, Brake Light, PDM, CAN modules, or any other PCB application is cost as made with the new Materials and Processes.
Examples for PCB costing
The GA Tech HyTech Racing team publishes their PCB data on their github, which was heavily used to benchmark the new Cost Catalog items. The Cost team generated some examples in the following Google spreadsheet using HyTech Racing’s PCB info as well as some fake boards. There may be minor errors in these spreadsheet examples versus the online Cost Catalog as they were used during the development process; always default to the names and prices in the Catalog if there is a discrepancy.
https://docs.google.com/spreadsheets/d/1A60q6OdLXBeLd6fF9Tw_kuYs_wwqkEOWugrBB-2WAgg/edit?usp=sharing
What else changed?
We’ve reduced the bulk of the electrical materials in the online cost catalogs. Most of the LV and HV wiring materials and processes have been reworked, consolidated, and updated. Wire Signal and Wire Control have been consolidated to one item: Wire, Signal and Control. HV wiring has been shuffled around similarly.
The Engine and Drivetrain section has been renamed to Drivetrain and given the prefix DT.
Several sections have been added to the Cost Supplement:
CS.2 DRIVETRAIN – ELECTRIC CLASS, an analog to the IC CLASS section above it
CR.8.2 HV Wiring Types – Clarifying the difference in HV and LV wire
CR.8.3 Wiring Harness Manufacturing – Describes how to cost a wiring harness in the online module
CR.8.4 Printed Circuit Boards Manufacturing – Describes how to cost a custom PCB in the online module
CR.8.5 Decision Workflow for costing an Electronic Module as Made or Bought
Closing Thoughts
If something is missing, please submit an add item request via the eAIR process on FSAEonline.com.
https://www.fsaeonline.com/page.aspx?pageid=50180e22-e55e-4a9f-8e4d-d19766d6962f
All questions regarding the Cost Catalogs can be answered via rules inquiry on FSAEonline.com.
The overall vehicle cost is only a portion of the Cost Event score – teams with “expensive” cars should not continue to write off the event, especially with these changes that impact the cost of their vehicles. I’d like to remind the teams that the top 10 vehicles in Cost at FSAE May 2022 had costs spanning $7500 to $17200. Frankly, the team with the $17200 report had the best report I’ve ever seen, and their score reflected that. The teams with the most accurate reports, clear and comprehensive documentation, and logical, well-thought-out Real Case Scenario presentations will be the most successful in the Cost and Manufacturing Event and place higher in the overall competition.
Do it right or do it twice.