This page goes over the details of which lights boards we have in the car and the required details for driving them and for heat dissipation calculations.
Tmax Tjmax = XX 100 degrees C Look at LED lifetimes vs operating temperature - LEDs have very high lifetime, but it seems like light output decreases when temperature rises. We will chose 100C as upper limit for Tj
Tamb = 35 degrees C Max ambient temperature (car temp on hot day in desert)
LED Thermal Resistance
Check datasheet for LED thermal resistance - it depends on the color of the LED. Use the typical values
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LED Color
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9
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We want to ensure that our Boost LED Drivers are able to drive all of the LEDs that we will be using. This table will go over the required parameters to check this. Vf is the most important parameter for this, and must be significantly higher than the input voltage of the board to ensure that accurate regulation is achieved. Check datasheet of LED driver for more specifics.
ASC Requirements
ASC Reference DRLs - Custom Dynamics TF6WC - 6 Genesis White SMD LEDs 6500K
ASC Reference BPS Strobe - same as DRLs
ASC Reference Turn - Fairly dim (1 LED would be brighter)
ASC Reference Brake - Same as turn, but red.
WSC Requirements
Board |
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UNECE Name | Color | Min Cd | Max Cd | LED |
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Count | Total Vf |
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Worst Case Power Dissipation
Max Thermal Resistance to Ambient
Daytime Running Lights
White
6
6 x 2.9 = 17.4V
17.4V x 0.35A = 6.09W
(50 - 35) / 6.09W = 2.4
Side Turn Indicators
Amber
Rear Brake
Red
Chosen Drive Current | Driver Type | |||||||
|---|---|---|---|---|---|---|---|---|
DRLS | Daytime running lamps | White | N/A | N/A | 7 | 20.3 | 300mA | Boost |
Top Brake | Center high mounted stop lamp, S3/S4 | Red | 60 | 260 | 4 | 8.8 | 300mA | Buck |
Rear Brake | Stop Lamp. S1/S2 | Red | 60 | 260 | 4 | 8.8 | 300mA | Buck |
Rear Turn | Rear direction indicator | Amber | 50 | 1000 | 4 | 8.8 | 200mA | Buck |
Front Turn | Front direction indicator | Amber | 175* | 1000 | 4 | 8.8 | 300mA | Buck |
Side Turn | Side direction indicator | Amber | 0.6 | 280 | 1/2? | 4.4 | 100mA | Buck |
BPS Strobe | N/A | White | N/A | N/A | 1/2? | 5.8 | 200mA | Buck |
*During WSC, the DRLs do not need to be on, so we use the requirements for >40mm from DRLs.
For some reason, the BPS strobe is also judged against the same standard for the DRLs - let’s get one in and test it.
Cd requirements for WSC, and LEDs for each light: Very good reference that provides clear images and examples of all types of lights in the UNECE regulations: https://www.hella.com/hella-ro/assets/media_global/673_Legal_Requirements_Brochure_HELLA_EN.pdf
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