SL-C Electrical System
Design and Planning Tools
The following tools are being used to design and plan the electrical system.
I'm going with and end-to-end MoTec system for engine management, traction control, display, logging, etc. Here is where I'm at:
| Qty. | Part Number | Description | Unit Price | Ext. Price |
|---|---|---|---|---|
| 1 | M130 | MoTeC ECU | $2,340.00 | $2,340.00 |
| 1 | GPR | MoTeC GPR Package (traction control, launch control, etc.) | $1,160.00 | $1,160.00 |
| 1 | MoTeC Level 2 Logging | $375.00 | $375.00 | |
| 1 | MoTeC C127 7” Color Display | $2,680.00 | $2,680.00 | |
| 1 | MoTeC C127 Display Creator (software enable) | 0 | ||
| 1 | MoTec C127 Enable I/O - 6 AV 2 AT 2 DIG 3 SPD 4 Aux Out | $463.00 | $463.00 | |
| 1 | MoTeC C127 Flush Mount Bezel | $178.50 | $178.50 | |
| 2 | MoTeC Bosch LSU 4.9 Lambda Sensor | 0 | ||
| 1 | LTC-D, Dual Lambda to CAN | 0 | ||
| 4 | MoTeC DHALL HS230, 3/8"-24 | 0 | ||
| 1 | 0280 026M, Bosch Fluid Temperature Sensor, 1/8" NPT - Engine/Oil Temp | 0 | ||
| 1 | Race-Spec 150PSIg, 1/8" NPT - Fuel/Oil Pressure | 0 | ||
| 1 | MoTeC 10hz GPS | $180.00 | $180.00 | |
| Total | $7,376.50 |
Information regarding the pressure sensor used for the master cylinders and clutch are located on the Pedal Box page.
Power Distribution
The kit ships with a nice power distribution system from Infinitybox, but I decided to upgrade to a couple of MoTeC Power Distribution Units (PDUs). Next step is to create a spreadsheet that maps out all of the electrical circuits to the PDUs, ECU and display.
Switches
I'm not crazy about the looks of MoTeC's keypads so I've started to look for some alternatives:
CAN Bus Switch Panels: 4. 6. 8. and 12
CAN Switch board
Nice generic keypads: http://www.blinkmarine.com
Nice CAN Bus controls: Grayhill
Battery Isolator / Kill Switch
https://www.youtube.com/watch?v=lMpTT-f72g0
https://racespeconline.com/products/msel-solid-state-battery-isolator?variant=13962734862379
Charge Ports
Battery
Several SL-C builders have used the Braille GU1R, it's small and lightweight. How to connect two batteries described here. The Antigravity ATX-20 looks great:
Weight: 4 lbs 11 oz (2.13 Kg)
Size: 6.875" x 3.44" x 6.125" (mm: 175x87x156)
Cranking Amps: 780
Amp Hours (pb Eq): 25
Negative Terminal Location: can be ordered on left or right
Max Charge Rate: 12 amp
Alternator
The alternator is a high-end, billet CS-130 style unit from MechMan. They estimate that B8165170M with a 54 mm pulley will generate 146 amps at idle. See card below (need to validate the actual ratios). Notes:
Higher output alternators require more effort to spin than a lower amperage alternator.
Serpentine belt applications should use a belt length that places the spring belt tensioner in the CENTER of it's travel. If the spring tensioner is too far outside of it's operating range in EITHER direction, the belt will slip.
G series alternators are rated to 18,000 RPM, while S and Elite series alternators are rated to 20,000 RPM.
ECU
The MoTeC ECU, GPS transceiver and digital display were delivered today. The quality of the case is outstanding not to mention the display itself. MoTeC appears to have their act together with respect to software and product modules. Many of the features in their embedded devices are activated via software keys. I assume the branded USB stick in the foreground does exactly that. It will be quite some time before I know for certain if MoTec is as good as their reputation, but so far I'm impressed.
Dual Half Bridge
Joel recommends either of the two dual half bridges
| MoTeC DHB | RaceGrade SSD 2 | |
|---|---|---|
| Price | $482 | $240 |
| Inputs | 2 | 4 |
| Outputs | 2 | 4 |
| Termination | Two DTP and One DTM Connector | Not teminated |
| Size (mm) | 31.4 x 38.0 x 14.0 | |
| Supply Voltage | 7v - 55v | 8v – 40v |
| Wire Size | 12 AWG | |
| Operating Temp. | -50° to 150° C | |
| Max. Steady State Current | 20A Total | 10 Amps per output (40 Amps total) |
| Peak Current | 500A (is this actually inrush?) | 50 Amps (thermally limited) |
| Peak Inrush Current | 100 Amps (transient pulse must be <100 μsec) | |
| Operating Frequency | 50 KHz @ 28v | DC to 1 MHz |
| Max Case Temp. | 125° C |
Rear view camera and monitor
Cutting edge rear view with integrated RADAR and overly graphics HERE.
Misc
Horn: Wolo (419) Bad Boy Air Horn - 12 Volt ($32.00)
Test Harness
I had Joel at RaceSpec make a test harness for me. I haven't had time to use it yet.
Deutsch Connectors
Most of the connectors will be Deutsch DT Series connectors. The manual, parts diagram and videos below provide pretty much all of the required information to install the connectors. When creating a custom harness and upgrading connectors on devices you can wire the connectors however you want. I'll use the following conventions:
The plug connector (i.e., the male part with the female sockets) will be installed on the vehicle’s wiring harness. The reason for this is that if the connector is left disconnected and live, it would be nearly impossible for a foreign object to be lodged inside the connector creating a dead short.
The wires on the plug connector are numbered and the following convention will be used:
Two-wire connector
Ground
Power
Four-wire connector for two devices
Device One Ground
Device One Power
Device Two Power
Device Two Ground
| Series | Max Current | Contact Size | Contact Style | Contact Plating | Wire Range |
| DTM | 7.5 | Size 20 | Solid | Nickle or Gold | 22-18 |
| Stamped & Formed | Nickle | 20-16 | |||
| DT | 13.0 | Size 16 | Solid | Nickle or Gold | 20-16 |
| Solid – Green Stripe | Nickle or Gold | 16-14 | |||
| Stamped & Formed | Nickle | 18-14 | |||
| DTP | 25.0 | Size 12 | Solid | Nickle or Gold | 14-12 |
| Stamped & Formed | Nickle | 14-10 |
Other tools
The Stripmaster wire strippers from Ideal are really nice.
Design Tools
I’ve been playing around with RapidHarness to design the harness.