Newbie question from person with no electrical skills. Please read.

Nokia6600 · 02-29-2004, 08:59 PM

I have bought this car kit http://store.mini-box.com/ituner/carkit.html

I have understood this much: The PW-70a Micro Power supply is of course the power supply for the motherboard, this PSU can provide up to 100 watt and more. The principle is the same as for a normal PSU that need 110/220V for a desktop computer but this PSU need a constant of 12V. Here is the problem because cars doesn’t give exactly 12V, it can spike up to 15-16 (because it need more power to charge the battery) and get as low as 8-9 when cranking the car. This is a problem because then the PW-70a cant provide enough power to the motherboard and the computer shuts down.. Am I correct so far? Please correct me if I am wrong somewhere. This is just what I believe so I hope some of you guys could comment and correct me if I am wrong.

Here is where the ITPS http://store.mini-box.com/ituner/itps.html comes in, this “tool” converts the battery power to 12V, converts it down to what the PW-70a PSU needs to operate the motherboard (12V) and have a overload protection and. And its able to shut down the computer safely if the car cant provide enough power, for example when cranking.
The V can go as low as 5-6 V when cranking the car because the starter consumes a lot of power to get the motor running. So the ITPS safely shuts down the computer and starts it again when there is enough power.. Correct, everything correct here? Please comment guys. This is REALLY bad for me, I want to have my carputer running the whole time, and have it running while I start the car. All this correct?

How can I fix this?
I was thinking about putting in a second battery, a small 12V motorcycle battery and serial connect it with the car battery and have a relay between so that the car doesn’t steal the power from the motorcycle battery as well when cranking the car. Then connect the ITPS to the motorcycle battery. Then I wouldn’t have the problem that the cranking of the car made the voltage drop and I would have a constant voltage to operate the ITPS the whole time? What do you guys think? Is this just a stupid idea from a person that doesn’t have a clue about electronic? What other way can I fix this “Computer shuts down while cranking problem”. Is it a lot of faults in this text. Can you guys comments please.. Thank you ALL so very much for taking the time to read all this “bull****” and I would be SO happy if some of you guys could comment on what
I have been written, would it work?, this isn’t the case!, you are mistaken,! this isn’t true! etc etc

Update. Here is a drawing of the "thingy" I was thinking about.

The diode I was thinking about using
1N4004 1A 400V Diode

The specs for the diode

And fiinally the motorcycle battery I am going to use

I am very sorry for my bad English.

Birrman54 · 02-29-2004, 10:32 PM

Quote: Originally Posted by Nokia6600

I have bought this car kit http://store.mini-box.com/ituner/carkit.html

I have understood this much: The PW-70a Micro Power supply is of course the power supply for the motherboard, this PSU can provide up to 100 watt and more. The principle is the same as for a normal PSU that need 110/220V for a desktop computer but this PSU need a constant of 12V. Here is the problem because cars doesn’t give exactly 12V, it can spike up to 15-16 (because it need more power to charge the battery) and get as low as 8-9 when cranking the car. This is a problem because then the PW-70a cant provide enough power to the motherboard and the computer shuts down.. Am I correct so far? Please correct me if I am wrong somewhere. This is just what I believe so I hope some of you guys can comment and correct me if I am wrong.

Here is where the ITPS http://store.mini-box.com/ituner/itps.html comes in, this “tool” converts the battery power to 12V, converts it down to what the PW-70a PSU needs to operate the motherboard (12V) and have a overload protection and. And its able to shut down the computer safely if the car cant provide enough power, for example when cranking.
The V can go as low as 5-6 V when cranking the car because the starter consumes a lot of power to get the motor running. So the ITPS safely shuts down the computer and starts it again when there is enough power.. Correct, everything correct here? Please comment guys. This is REALLY bad for me, I want to have my carputer running the whole time, and have it running while I start the car. All this correct?

How can I fix this?
I was thinking about putting in a second battery, a small 12V motorcycle battery and serial connect it with the car battery and have a relay between so that the car doesn’t steal the power from the motorcycle battery as well when cranking the car. Then connect the connect the ITPS to the motorcycle battery. Then I wouldn’t have the problem that the cranking of the car made the voltage drop and I would have a constant voltage to operate the ITPS the whole time? What do you guys think? Is this just a stupid idea from a person that doesn’t have a clue about electronic? What other way can I fix this “Computer shuts down while cranking problem”. Is it a lot of faults in this text. Can you guys comments please.. Thank you ALL so very much for taking the time to read all this “bull****” and I would be SO happy if some of you could comment on what
I have been written, would it work, this isn’t, you are mistaken, this isn’t true etc etc

I am very sorry for my bad English.

You're looking for a tank circuit:

http://www.mp3car.com/vbulletin/power-supplies/20359-battery-based-tank-circuit-tested.html

birrman54