NooB Question about powering a laptop using M2-ATX

**compuwengo** · 07-28-2009, 05:25 AM

Hi All,

I am planning to gear up my own Carputer using my old Acer Laptop.
I have been searching and reading a lot of forum posts for my question.

I found many people placing laptops for carpcs and they have excellent solutions for auto power up / shutdown.

From what all i have learned till now i have tried to put up a design to power my laptop, screen and devices
I will be using M2-ATX (instead of CarNetix 1900) incase my laptop dies and i have to switch to a PC.

Question i have is

When i power down Ignition of my car, the laptop will still be connected to the Car battery from M2-ATX. Thus laptop will continuously draw power from car battery to charge laptop battery. Wont it kill my car battery?
Or M2-ATX cuts the power to the laptop when ignition is cut off.

Consider me a total noob in powering

Thanks a lot

**DigitalVampire** · 07-28-2009, 05:31 AM

Unless you have a notebook which charges/works from 12V, M2ATX will not be able to power it. Most laptops which I'm aware requires and input of 19V which M2ATX is not designed to generate.

Carnetix 1900 is your best bet if you are using a laptop. If you are on a budget, a Car adapter for the laptop may be a good deal but it would be limited when compared to Carnetix 1900

**compuwengo** · 07-28-2009, 05:46 AM

Originally Posted by DigitalVampire

Unless you have a notebook which charges/works from 12V, M2ATX will not be able to power it. Most laptops which I'm aware requires and input of 19V which M2ATX is not designed to generate.

That is why i am adding a 12v-19v DC Car Adapter for Laptop

Originally Posted by DigitalVampire

Carnetix 1900 is your best bet if you are using a laptop. If you are on a budget, a Car adapter for the laptop may be a good deal but it would be limited when compared to Carnetix 1900

If i use only Car Adapter then what about the power that laptop will keep drawing from car battery even after powering down the ignition.

**DarquePervert** · 07-28-2009, 06:03 AM

Originally Posted by compuwengo

If i use only Car Adapter then what about the power that laptop will keep drawing from car battery even after powering down the ignition.

Wire it to an ignition-controlled circuit so the power to the car turns off with the ignition.
You can do the same thing with a relay, as well.

**compuwengo** · 07-28-2009, 06:09 AM

Thanks DarquePervert,

In case i power my laptop to Ignition Controlled circuit, then also i would need power for my devices. Can i power my other devices (LCD, SoundCard, etc) also from Ignition Controlled Circuit?

More over in that case, i guess, i would need a SSC for controlling startup and shutdown.

Please tell me will it work if i put in a Car Adapter ahead of M2-ATX as in my design?

**Sicarius** · 07-28-2009, 10:49 AM

The M2-ATX will hard-off the 12v line after a preset amount of time depending on how you set J10.

**DarquePervert** · 07-28-2009, 10:53 AM

Originally Posted by Sicarius

The M2-ATX will hard-off the 12v line after a preset amount of time depending on how you set J10.

The M2ATX is completely unnecessary for a laptop install.
You completely missed the boat.

**compuwengo** · 07-28-2009, 11:06 AM

@Sicarius : Thanks, you answered my question

@DarquePervert : I would love to know more, Let me know how would i power my other devices.

**compuwengo** · 07-28-2009, 11:13 AM

I think DarquePervert is pointing towards something like this.

In this case what about other devices? Other 12v and 5v Devices. Should i power all to Ignition Controlled Ckt?

**DigitalVampire** · 07-28-2009, 12:22 PM

Originally Posted by compuwengo

That is why i am adding a 12v-19v DC Car Adapter for Laptop

I totally missed your wiring diagram. My office firewall filters all image attachments.

Now that I'm home, I see your wiring diagram, but still believe it is a very inefficient setup and adds to the cost. 2 DC-DC converters in series!!!

Originally Posted by compuwengo

I think DarquePervert is pointing towards something like this.

In this case what about other devices? Other 12v and 5v Devices. Should i power all to Ignition Controlled Ckt?

This looks good as long as your screen is tolerant to voltages upto 14.4V or sometimes even higher. I'd add a 12V regulator for the screen to be on the safe side