dasoviet

Hi,

I did a bit of searching before posting this.

I am about to setup a carputer. Actually the computer is ready and the touchscreen.

What i want though is to have instant access on the computer while a get in the car.
Practically this cannot happen as the best windows load i can get is 30secs.

Then i thought, to install a second battery in the trunk that it will be connected with the computer. Then the computer's power switch will be connected to the remote control. Therefore when i press the "unlock" button on my remote the computer will boot up.

The battery should be isolated from the main battery thus not to discharge it. I woudn't mind if the computer battery discharge.

My question is, does the alternator afford to keep alive the second battery?
Would a second a second battery (isolated) will harm in anyway the electronics of the car?

I've had a talk with an car electrician specialist and he told me that a second battery could kill the alternator and the burn the ECU of the car.

I would appreciate in kind of feedback!

StealthTL

iTrader: (1)

It is always a good idea to provide a second battery in a "carputer" install - the main battery voltage will dip to the point where the 'puter will switch off/reboot when the starter motor is used.

You dont need much of a battery, just one of those little motorbike units will do. Run the computer off this battery, and re-charge it from the main thru a large diode, to prevent the voltage dropping as the car starts.


S

lurch519

or, you can get a ide flash drive, load times are much faster than hard drive loading as its is flash based

dasoviet

I want to have a full windows installation. i think i will install a 12v 7ah battery and have it charged throught the back power socket.

The back power socket says max 10A. Do you know what happens if i want more than 10A? Will the car's electrical system fail or something?

Thanks!

StealthTL

iTrader: (1)

"More than 10 amps..." is a lot of power!

The fuse to that socket is a 20 amp, so I don't see any real problem.....


S

lurch519

Most computers draw way more than 10 amps of current, and thats at 120 volts.

http://www.mini-itx.com/store/?c=16

this is what i was referring to, you can use a flash card (available up to 8 gigs last time i checked, and only install the minimun needed to load windows, and have everything reside on a conventional hard drive

Chamberlin

iTrader: (1)

my stock battery dipped below the minimum voltage last night for the first time, and the Opus turned everything off just fine, and I was still able to start the car.

I thought about the second battery too (look into isolators on RV web sites) but I thought I remember hearing from someone else that a beefier alternator was needed to charge both....or a second alternator.....but instead I have decided to get a yellow top Optima deep cycle battery and call it a day.

have you experimented with hibernation and standby ?

-C

Chamberlin

iTrader: (1)

Yea, but can you flash load Windows XP? I thought you can just do embedded CE or Linux.... I don't think most people are willing to go that route....

Let me know if I'm wrong though, as my MII already has the compact flash riser card.... would love to do it.


-C

dasoviet

With CF the load times are faster beacause windows have been shrinked and NOT because CF Reading is faster that a 2.5" HD.

I still can do a Windows XPe installation but i don't want to get into that kind of trouble.

Anyway i just bought a 12V 7Ah battery those that are used in UPS' and give it a try.

truemagellen

for a car computer you do not need a second battery, instead an intelligent DC to DC power supply unit for the carputer

there are many out there (including the one I put in my modded xbox) that has a switch built in so I have it powered direct from the battery but the psu shuts it down based on a 12v power source as a relayed switch (I went with the center console).

Then for XP get XP lite...it will boot much faster and you will want it to slip in and out of hibernation anyhow. Get lots of ram and a flash drive like lurch said this way your hibernated state is loading from a fast booting flash drive. Then keep data on a secondary drive (ata tech is fine).

To speed up xp you can also change boot order...modify the bios to remove testing...etc.

check this out:

http://www.litepc.com/

airspeed

I got the carnetix dc to dc power supply and there is a pulse input to tap the signal from the remote thru the car alarm. this will enable the pc to boot up when u unlock using the remote. it will also prevent battery discharge as it will cut the power once it detects engine off and low batt voltage.

dasoviet

My budget is limited so i cannot get a huge flash.

I tried litepc.com but it needs loads of testing to anf i need to find out which services/features i really need. I did a full installation and now i am stopping services removing features to lite up my installation and make boot time faster.

Tiny XP on the other hand could not handle my TV tuner so i went back to Win XP PRO

When i am done with all the installation i will use minlogon.exe istead of the traditional winlogon.exe. I hope it will help. Many ppl in mp3car.com is using minlogon and it is much faster. than the winlogon/

For PSU i have the M2 ATX which i believe it is fairly a good solution.

My thought of the second battery is to install a relay switch in a line where it would short a circuit when i unlock the car and it will boot the computer.

Do you know a source to put the Relay switch.

Another Question. Does anyone has a diagram of the radio antenna cable (where is it coming from). I bought an extension cable (for the tv/fm tuner). it will be better to have it as short as possible the antenna cable.
It should be somewhere in the trunk innit?
My computer is in the trunk as well.

dsmdriver

iTrader: (3)

Dude, you're on crack.

Most power supplies are 300-400W for a full size desktop PC. This is only 3-ish amps at 120V, and this assumes the PC is using all of that power. 10+ amps at 120V is 1200+ watts.

truemagellen

Yes no way on 10amps. The xbox uses 6amps at 12volts

You are thinking 10amps at 12 volts for a lower power pc which convienently equals 120watts.

Forget spending time to get the TV tuner working it is a waste of time...you can't get an antenna big enough to grab the signal without massive noise...even an amplified diversity antenna does not work.

dasoviet

How about the FM tuner? It should work with the car's antenna right?

My car is a Japan import and the HU's FM frequency range is different in asia.

My PC as it is configured now it draws about 70-80W which i believe is OK.

If i had an epia or something similar it would 50W or less. Nevermind my budget is limited so i bought a value all-in-one mobo.

truemagellen: do you have the wiring diagram of the car antenna?

Thanks!

truemagellen

FM tuner will work fine

just tap the antenna behind the head unit

do u have a stock nav by chance?

FastRX8

The antenna is located on the rear deck. There are wires that connect it to the rear window. In my car, it looks like a small black box. I have the bose system but I assume it's the same on all.

dasoviet

I bought the navigation motorised monitor from a part seller here in Cyprus. Its a guy who keeps whole cars for parts. I bought about $450 Dollars and then another $400 for the Xanarc 7" TSV.

Putting the Xenarc into the navigation it was a bit difficult for me. For almost a month i couldn't decide whether i should cut a small part to have the Xenarc fitted exactly and 100% view of the monitor or have that 4mm behind the plastic.

Finally i did cut those 4mm and now i have 100% view of the monitor. I used a knife and "tons" of sand paper hard and soft as well :P

anyway that was my experience.

Now i have to refit the xenarc into the navigation because it has an angle to the left of about 1o degree (not viewable from 50cm distance). I want to have it perfectly fitted and 10000% factory look!

Truemagellen: I am looking for the blank trim for the HU. I have the MD installed. And i want to get rid of it to put on the AuxMod. so i will need the blank trim.

truemagellen

What firmware do you have?

Click 'text' and 'preset1' and it will tell you.

dasoviet

its 9.55

truemagellen

You can simply order the PIE auxiliary input with RCA ins. That will provide a crystal clear audio input...and you can leave the MD part.

If you want to control your Carpc with the steeering wheel you can buy the PIE unit and then there is a pc unit that combines with it and provides audio in.

dasoviet

I already have the Syflex AuxMod.

I haven't installed it yet. Hope it works.

One of my options was the PIE but because i have the OEM MP3 player i didn't want to get rid of it

truemagellen

The OEM Mp3 player doesn't affect the port PIE uses.

dasoviet

Someone in the forum told me that it does.
Anyway...

RotorManiac

back to the original question dasoviet asked, why do you say that 30secs for a pc to boot up is way too long (my car pc does about 35secs)? I mean, come on, its not a lifetime and you can do it only once in the morning, the stock battery is fine for using hybernation during the day, when you are moving around. its takes only seconds to boot up...