[badboyscad]

Originally Posted by sdh

I measured voltages at the battery termnal:
With engine running: 14V
With engine off and ign key mid position: 12.5 volts

Still without engine runninig, the computer shuts down after about 30 seconds. Why?

Is you PSU similar to the M2-ATX HV PSU?? Are there any jumpers for different power settings? If yes, then check and make sure whether the HARDOFF setting is correct.

M2-ATX HV PSU jumper settings:

[shldn]

Originally Posted by sdh

Still without engine runninig, the computer shuts down after about 30 seconds. Why?

Measure the input voltage between ign & ground at the pc when the computer shuts down, it will most likely have dropped to near 0.

Where exactly have you tapped the ign signal from ? It could be that your ign tap point goes 'live' only momentary when the key is turned ( but engine off ) which is enough to sent a startup signal but is off after that and as a result the psu shuts down the pc after 30s as programmed. If so, you may have to tap the ignition signal at a different location.

M2-ATX & SB-160D Jumper config is not the same, interchanging the jumper configs between the boards may cause undesired results.

[sdh]

Originally Posted by shldn

Measure the input voltage between ign & ground at the pc when the computer shuts down, it will most likely have dropped to near 0.

Where exactly have you tapped the ign signal from ? It could be that your ign tap point goes 'live' only momentary when the key is turned ( but engine off ) which is enough to sent a startup signal but is off after that and as a result the psu shuts down the pc after 30s as programmed. If so, you may have to tap the ignition signal at a different location.

M2-ATX & SB-160D Jumper config is not the same, interchanging the jumper configs between the boards may cause undesired results.

I have connected the 12v, Ign and Gnd lines to the computer from the Car Stereo power connector available in the dash. The jumper setting for the PSU is B1 and B3 are set to 0 by putting jumpers.
I have done another simple test, and still the computer shuts down. From full off state, I turn the ignition half way, the computer comes on fully and starts shutting down after few seconds.

I did measurements on 12v line and values are as follows:
Car fully off: 12.8V
Key turned to ACC position: Voltage drops to between 9 and 10 volts (dipped to as low as 8 volt in between).
The PC came on and then shut down due to 11 volt trigger setting.

Now the big question is why is the voltage dropping so much? Is this normal?

I will try and reporduce the shutdown scenario with engine running in the mean time.

[badboyscad]

Originally Posted by sdh

I did measurements on 12v line and values are as follows:
Car fully off: 12.8V
Key turned to ACC position: Voltage drops to between 9 and 10 volts (dipped to as low as 8 volt in between).
The PC came on and then shut down due to 11 volt trigger setting.

Now the big question is why is the voltage dropping so much? Is this normal?

Just now took the same measurements(on battery terminals) in my scorpio

Car fully off : 12.4V
key turned to ACC postion : Voltage drops to 12.1V
While IGNITION(cranking up) : Voltage drops to 11
Engine started and running :14.1V (maximum).

So, i guess there is something wrong in your situation. Voltage shouldn't drop so low at ACC postion.

[shldn]

sdh, the stock wiring on your car stereo power connector is not adequate for powering your carpc even if it an atom based system. Your voltage is dropping because of this. You also run a serious risk of overheating those wires and even a fire. Please see the sticky on the top of the DIY Section, So.... why do we need those thick wires??

For just the CarPC power lines you require atleast 12AWG size wire, wired straight to the car battery. If you are running an amplifier also along the same line you are looking at minimum 8 AWG. The ignition signal wire can be around 16-18AWG. Your voltage at the pc input terminals should be very close to the actual battery voltage. Please have your wiring upgraded at the earliest.

Your ignition switch on the steering column can have multiple contact positions ( depending on make/variant etc. ) for switching various accessories, hence tapping the signal at any one position or the car audio connector ( if wired different ) might not always work.

Hence you require to check the ign voltage at the pc input to see if it drops to near 0 when the engine is off, this could be your culprit and not the under voltage protection on the PSU. The cigarette lighter terminal may be a good point to tap the ignition signal, please check with a multimeter.

[sdh]

Originally Posted by badboyscad

Just now took the same measurements(on battery terminals) in my scorpio

Car fully off : 12.4V
key turned to ACC postion : Voltage drops to 12.1V
While IGNITION(cranking up) : Voltage drops to 11
Engine started and running :14.1V (maximum).

So, i guess there is something wrong in your situation. Voltage shouldn't drop so low at ACC postion.

Thanks for ur measurements. Can you do one check for me. Leave the key in ACC position and see if the voltage drops once the comp and amps are fully operational. With engine running, I also have 14+ volts.

[SirAlec]

what is the cost of just cpu and supply.

[badboyscad]

Originally Posted by sdh

Can you do one check for me. Leave the key in ACC position and see if the voltage drops once the comp and amps are fully operational.

Did the above check, Key was is ACC mode.

Computer started : 12.1V
Amplifier starts while computer boots :12V
Immediately after amp start sound(pop sound) : 12.1V
Computer ON, 2 amplifiers ON (4channel and 2channel), Music playing with subwoofer : 12.1V constant.

[sdh]

Originally Posted by shldn

sdh, the stock wiring on your car stereo power connector is not adequate for powering your carpc even if it an atom based system. Your voltage is dropping because of this. You also run a serious risk of overheating those wires and even a fire. Please see the sticky on the top of the DIY Section, So.... why do we need those thick wires??

For just the CarPC power lines you require atleast 12AWG size wire, wired straight to the car battery. If you are running an amplifier also along the same line you are looking at minimum 8 AWG. The ignition signal wire can be around 16-18AWG. Your voltage at the pc input terminals should be very close to the actual battery voltage. Please have your wiring upgraded at the earliest.

Your ignition switch on the steering column can have multiple contact positions ( depending on make/variant etc. ) for switching various accessories, hence tapping the signal at any one position or the car audio connector ( if wired different ) might not always work.

Hence you require to check the ign voltage at the pc input to see if it drops to near 0 when the engine is off, this could be your culprit and not the under voltage protection on the PSU. The cigarette lighter terminal may be a good point to tap the ignition signal, please check with a multimeter.

Thanks Sheldon. Made the wirring changes. 12awg wire directly from battery to car comp and the voltage is stable now. I have no fuse installed. Should I put one?

[gigy]

dose it switch off in 'acc' position or 'on' position?

[shldn]

Yes, an inline fuse is a good idea.

[sdh]

Originally Posted by shldn

Yes, an inline fuse is a good idea.

what should be the value?

[badboyscad]

Originally Posted by sdh

what should be the value?

Im using a 10amps blade fuse for my scorputer setup.

[shldn]

10-15A should be adequate

[sdh]

New stuff just acquired:

ADS Tech Instant FM -RDX155
Holux USB GPS receiver GR-213U
Elm Scan 5 Bluetooth.

Tested FM radio and GPS with laptop, looks working. Radio reception is quite clear in home environment. GPS also worked indoors, about 3-4 feet from window.

Will move these parts to car soon and report working with CF. Any clue where is the Diagnostic Link Connector (DLC) on Swift. I believe it is somewhere between steering column and centro console of the car.