Portable Rasberry Pi with monitor advice needed please

[antolanca]

Hello guys and girls.

I'm really falling in love with Raspberry Pi style computers and I would like to make a portable one. However I would like to use an old laptop, get rid of it's motherboard and then replace it with a Raspberry Pi and re-use the laptop's monitor. I would install a 12V 6800mAh battery which already comes with a charger.
Now the monitor needs 12V 1A and the Pi 5V 2A so I've been thinking as to how would I power both of them from the mains and/or the battery. I've attached a simplified diagram as to how I would connect it so could anyone have a look and let me know if there are any problems please?
Below you will also find the parts I'm planning to buy to power this.

Battery with transformer - https://www.amazon.co.uk/Enjoydeal-Portable-6800mAh-Rechargeable-Li-Polymer/dp/B01D9ZWC0I/ref=sr_1_fkmr0_4?s=electronics&ie=UTF8&qid=1466137015&sr=1-4-fkmr0&keywords=12v+6800mAh+battery

12V to 5V converter - https://www.amazon.co.uk/gp/product/B00ENE55SQ/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A1O6C23YCTW0U1

[stefanh]

There is the "pi-top" product available if you wanted something ready made, although it is quite expensive.

https://www.pi-top.com/product/pi-top

[Buriedcode]

Interfacing to a laptop monitor directly is no easy task - you'll need an LVDS board.  Also, does that battery-pack/PSU power the output when charging? or is the load in parallel with the battery at all times? If its the latter, the battery may not fully charge, but I'm assuming it has basic load sharing, making it a 'plug and play' type affair.

Its a nice idea, I still haven't bitten the Pi bullet yet, but was thinking along similar lines whilst making my life difficult for myself by using an FPGA for the monitor adapter.

[antolanca]

There is the "pi-top" product available if you wanted something ready made, although it is quite expensive.

https://www.pi-top.com/product/pi-top

Hence the idea of creating my own Single Board Computer Laptop. To be able to upgrade and/or replace the interior components in case of malfunction for the lowest cost possible. All of the components that I think I need (hence why this post) would cost around £130 when a Pi Top is £199.

Besides where's the fun in just buying what someone else has built when you can build it yourself?

Interfacing to a laptop monitor directly is no easy task - you'll need an LVDS board.  Also, does that battery-pack/PSU power the output when charging? or is the load in parallel with the battery at all times? If its the latter, the battery may not fully charge, but I'm assuming it has basic load sharing, making it a 'plug and play' type affair.

Its a nice idea, I still haven't bitten the Pi bullet yet, but was thinking along similar lines whilst making my life difficult for myself by using an FPGA for the monitor adapter.

You can get an LVDS for all sorts of Laptop monitors on Ebay from e-qstore (http://stores.ebay.co.uk/e-qstore). Their kit is pretty much "plug and play" and they are highly rated.
And the battery would be in parallel so I could charge the battery and power the computer at the same time (the switch is to switch off the computer completely and let the battery charge).

And thanks to you mentioning the load sharing, you made me think. And after a few hours research I have found an alternative for the battery. A 5V power pack with 4.5A (2.4A and 2.1A) and a MoPi to control the power to the Pi. All I need is a boost converter to 12V and it's done.

Boost converter - https://www.amazon.co.uk/gp/product/B00HLZNS0Q/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=AONS7HEF348I5

Power Pack - https://www.amazon.co.uk/gp/product/B00OFRAJ8W/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A296JJ7EW4ORVE

Even if the charging is only 5V 1.5A (7.5W when I need 22W) it's a much safer alternative to an RC battery. Also I might be able to boost charging with a higher amperage charger (5V 3A or more).

Thanks for the help guys. Will post the schematics later.

[antolanca]

And here we go. Did some sketches and figured out what to do. Have a look and tell me what do you think.