1. ## Problem Confused

I am trying to create a car PC that will cope with anything except games, but run for extended time with the car's engine off.

What is troubling me the most is trying to get accurate figures of total board power consumption. I was thinking of VIAs EDEN 1.2ghz board but have read it cant cope with mp4 video. They also quote power use of 7w but I have read reports of 20-30w

What I also do not understand is will I be better using a laptop system... ? My 1.7ghz centrino laptop has a 14.8v laptop and 4.5ah battery and runs for 3.5 hours screen on .. my simple maths puts that at a consumption of:

battery power 14.8*4.5*60 = 3996W

3996/3.5 = 1141.7 w used per hour

1141.7/60 = 19 w per min

average power use 0.32W

I have not done my physics for ages but that looks wrong ? ? ?

What is the best chip to look into Via Edan AMD geode or intel pentium M ? ?

If I want the best run time and still have total function??

MAIN QUESTION : how long does everyones computers run with the engine off and still be able to start. (computer spec also would be good)

2. My system has run over two hours at a meet with the engine off and has had no problem cranking afterward.

3. Hello! Your maths IS WRONG !
FIRST-YOU DIDN'T POINTED THE CURRENT WHICH TAKES YOURS LAPTOP! http://www.mp3car.com/vbulletin/images/smilies/mob.gif
Any battery have its own capasitance, which meters in Ampers per hour - you can see this value on the case of battery , marking in AH - example 12V 22AH - it means taht your battery can give current of 22 ampers in 1 hour , after one hour the current is fall and battery discharge very mutch and can damage if you don't charge it ! anoter - your battery can work with 2.2 Ampers about 10 hours , and then it will be have a critical discharge state!

Power meteres in Watts ( default - Energy per Hour - international marking - and its not pointed - because 1 Watt=1 Joulie per hour)
Power=current*voltage
another words
1Watt=1Volt*1Amper

Now let's look at praktice:
some one system has parameters like this:
1. Supply voltage 12 Volts
2. Current 10 A
3. Battery capasitance 15 AH

Let's math:

Power of the system = 12Volts*10Amps=120Watts
How mutch the system will work?: Battery capasitance/current=15AH/10A=1.5H

OK!
My 1.7ghz centrino laptop has a 14.8v laptop and 4.5ah battery and runs for 3.5 hours screen on
what do we have :
1. supply voltage 14.8
2. battery capasitance 4.5 AH
3. system works 3.5 Hours
Let's calculate the power of this system:
First we need to find current:
Current= Battery capasitance/Time
Current=4.5AH/3.5H=1.29 A
Second - the power of system= supply voltage * current =
14.8V*1.29A=19.1W
It's great - because you use this laptop with screen on ! And it takes little power , like small car lamp !
To calculate any system your need to know it's power, supply voltage and battery capasitance

4. Hi mibmib

Thanks ... Goes to show how fast you loose your physics... (A at A level and a S level distinction...lol )

Watt=1 Joulie per hour... you mean per second ??

that value looks a lot more realistic....

so back calculating .... the VIA 1.2 eden max 16W with a CF hdd no screen on

Current 16/12 = 1.33 A

car battery 40Ah / 1.33A = 30 hours..... (and prob will not start) so might get 18 hours

right .... now my next thought .... Intel has started to do Core Solo U1400 1.2GHz ULV chips ULV in laptops that run for 11 hours.... is this a marketing con?

QUESTION 1

In terms of power consumption and performance would I be better using a laptop chip over a VIA (low power being important)

Question 2

does the motherboard choice have a larger influance with power consumption than the CHIP?

thanks

5. Ok!

Watt=1 Joulie per hour... you mean per second ??
Yes! I have made a mistake - realy 1Watt=1 Joulie per second( 1Joulie/1second)
ok, another words- 1W*H=3600J ,note - energy meters in joulies or watts per hour ( watt*hour)
But another calculations are right !

right .... now my next thought .... Intel has started to do Core Solo U1400 1.2GHz ULV chips
ULV in laptops that run for 11 hours.... is this a
marketing con?
if you will be printing any text using word or notepad and nothing more - yeah - it will works 11 hours, but if you'll be playing some games or watching DVD ,
it will works 2-3 hours, because cpu and gpu would take full loads - 80-100% ? and takes more power!

so back calculating .... the VIA 1.2 eden max 16W with a CF hdd no screen on

Current 16/12 = 1.33 A

car battery 40Ah / 1.33A = 30 hours..... (and prob will not start) so might get 18 hours
7 watt ia a minimum power !- the system is staying- no music , no films , no internet, no gps,works only OS,
what do you think about cpu and gpu loads at this time?
Now just load your system using any game , music or dvd snd i think you will get that 20-30 watts,about you wrote upper.
Yours calculations are right ! But here is some bug - the "starting current " , which battery gives to starter when you start any car, will bee less, because battery have some discharge after you system works about 18 hours with engine off!
How muth it will be less i dont know.......

In terms of power consumption and performance would I be better using low power system ! which one ? just look at Docs and calculate.

I don't think so. I think it's a comlex task

p.s. sorry for my english , i am from Kyrgyzstan

6. lol what's a joulie?

do you mean a joule?

7. Е"у я что ли как там у вас Джоуля называют ! Ну туууупыыыыеее! С Задорнов !

8. Originally Posted by MibMib
Е"у я что ли как там у вас Джоуля называют ! Ну туууупыыыыеее! С Задорнов !

9. I said , that my english is not so good! And i don't know how to write some words Like Joule or Joulie - how right? And they are lolling on me , and i am crying !

10. thank you very much ... (I can spell either let alone in another language)

I wanted to use it to capture security video ... not sure how much load there is there.

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