Regulated Vehicle Power Supply Options

Published by Andrew Hreschak in research and planning, the hardware, power
Published on 11/20/05 @ 08:52:00 pm using 902 words, and has 18962 views

One of the trickiest parts of the Acura ITX project is that I'd like the system to be largely hands-free. The system will have a keyboard only as backup, and will rely on the touchscreen interface via the LCD panel.

When it comes to powering the system on and off, the plan is to have the computer wired directly into the ignition of the Acura CL, so when the car is turned on, the computer boots up, and with a kill-switch wired inline between the ignition and the computer, for those occasions when the headunit is preferred over the ITX system.

Here are the power supply options I'm currently considering. They each have their pros and cons.

OPUS120 12Volt 120W DC ATX Power Supply

OPUS120 120W 12V DC ATX Power Supply The 120W DC-DC Power supply has a micro-controller that controls and monitors various functions of the power supply operation. It monitors automobile battery voltage to protect against deep discharge. The Power-ON lead is monitored to start the PC when the power is turned on and to implement a safe shutdown procedure. It controls and monitors motherboard signals to provide smooth power-up and power down sequences. In addition, it also responds to shut down, stand-by and hibernate modes.

The power supply can be programmed to shut down the PC after a delay of time. Its outputs are monitored to assure proper PC operation. A green LED indicator in the power supply continually indicates the power system status and health. It is also used for troubleshooting. There are features that are built-in for trouble-free and safe PC operation. The input power is protected against transients, load dumps and double battery during jumpstarts. The PC does not reboot during engine start or cranking. It also uses state-of-the-art technologies and the most advanced techniques to maximize efficiency, performance and reliability. Simply put, there is no other PC power supply like it.

Here is a diagram of how the OPUS 120 is wired from the car battery to the computer system. This is a rather simplistic diagram and does not take into account the wiring via the vehicle's 12v ACC connection, nor the fused digital distribution block mounted in the trunk.

OPUS120 User guide (requires Adobe Acrobat)

M1-ATX DC-DC ATX Automotive Computer PSU

M1-ATX DC-DC ATX Automotive Computer Power SupplyM1-ATX is an intelligent vehicle (car, boat, electric cart, etc) 12V DC-DC ATX PC power supply. Designed to provide power and to control the ON/OFF switch of a motherboard (PC) based on ignition status, M1-ATX is a wide input (6-24V) vehicle or car DC-DC ATX power supply capable of surviving tough car engine cranks (down to 5.7V) as well as transient over-voltage situations.

M1-ATX Product Manual
M1-ATX Specs, including power ratings
M1-ATX User Guide
M1-ATX Schematic Diagram and Dimensions

This power supply provides a direct bridge between the vehicle battery and the computer system. It has onboard LDO (Low-voltage Drop Out) circuitry, and has 8 user selectable microcontroller driven timing modes, allowing you to choose up to 8 ignition/shutdown timing schemes via a built-in shutdown controller. It can be purchased for approx $75 from various vendors specializing in vehicle computing electronics.

M2-ATX 160W ATX Power Supply

M2-ATX 160W 12V ATX Power Supply M2-ATX is an intelligent, high power, vehicle (car / boat / electric cart) 12V DC-DC ATX PC power supply designed for car pc and battery powered applications. Designed to provide power and to control the ON/OFF switch of a motherboard (car PC) based on ignition status, M2-ATX is a wide input (6 to 24V) vehicle / car / battery operated ATX power supply capable of surviving tough car engine cranks (down to 6V) as well as transient over-voltage situations.

The M2-ATX comes with complete cable harness consisting of:

  • ATX cable extender plus HDD and Floppy power (9inch)
  • Power input cable harness terminated in 0.25' fastons (12inch)
  • 2 pin M/B on/off power ON control wire harness (9inch)
  • set of LBJ (little black jumpers) to control various power sequencing schemes

M2-ATX Product Manual (English)
M2-ATX Specs, including power ratings
M2-ATX Schematic Diagram and Dimensions
M2-ATX Undocumented shutdown timings

M2-ATX has 8 user selectable microcontroller driven timing modes, allowing you to choose up to 8 ignition/shutdown car pc timing schemes via a built-in shutdown controller. By removing all user-selectable jumpers, M2-ATX becomes a traditional PC PSU with no ignition control (shutdown controller bypassed) and it can be used in non-vehicle computer applications.

Alternate option:
80W DC-DC Power Supply 12V Output from Opus Solutions. This system provides most of the same features as the m1-ATX power supply, including a micro-controller that controls and monitors various functions of the power supply operation. It monitors automobile battery voltage to protect against deep discharge. The Power-ON lead is monitored to start the PC when the power is turned on and to implement a safe shutdown procedure. It controls and monitors motherboard signals to provide smooth power-up and power down sequences. In addition, it also responds to shut down, stand-by and hibernate modes.

However, the Opus 80W Supply is not compatible with the EPIA M-series of mainboards, as the M-series requires a standard ATX power interface. The Opus Power Supply is designed for motherboards with 12V input power. Since the Acura ITX project will use an EPIA MII-12000 mainboard (for the onboard CompactFlash and PCMCIA slots), the Opus power supply is not exactly suitable to this project, but is listed here for reference.

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5 comments

Comment from: moris [Visitor]  
moris

Nice post.Many many thanks for the tips.

02/23/10 @ 06:03
Comment from: ThaiCar [Visitor]  
ThaiCar

Good post. Thank you for this.

04/23/10 @ 01:13
Comment from: Car [Visitor]  
Car

VERY USEFUL POST.THANK YOU FOR SHARING THIS.

04/24/10 @ 02:44
Comment from: leadrem [Visitor]  
leadrem

HI there,

The power supply options are quite technical in vehicles!

Thanks,
Ken

12/02/10 @ 05:39
Comment from: wifir [Visitor]  
wifir

OPUS120 12Volt 120W DC ATX Power Supply is a quality product. I had to install it myself by it’s quite durable.

07/26/11 @ 11:43