Build a laptop with a Thin Mini ITX setup?

Question

I'm planning to build my own laptop for custom reasons and realized I may mainly hit some power-related problems. Unfortunately, no answer can be found concerneing Thin Mini ITX boards.

Considering that a 3x10 12v battery pack will do it, there's still a vdrop -or even vdrrop- that need to be handled.

So the question is: Is there any pre-made 12v (battery pack) to a stable 12v 10A voltage regulator ?

The problem is they seems to be nowhere to be found and the closest thing I have is a 7812 regulator (https://www.radioshack.com/products/radioshack-12v-fixed-voltage-regulator-7812?variant=20332038341), which is unfortunately not enough.

(more questions may come, I will edit the post accordingly)

Original question: will things works just fine if I power the motherboard with a -correctly packed- AA or AAA battery pack ?

Now the details:

• Is any power regulator's needed ? (A power inverter for cars is not a good solution) -> Edit: Yes for a power regulator, you don't want a vdrop or even vdroop when the batteries are depleting.
• Thin Mini ITX motherboards often comes with a single power input that can be switched from 12V or 19V, thus allowing them to be battery-powered more easier than normal Mini ITX boards.

• Also, they do often have an LVDS port, which just make things even easier to connect a laptop display.

• The power draw will surely get higher than laptops. This will be avoided by including a bigger battery pack, underclocking and undervolting is also planned to fit laptops' CPU specifications.

• But such Thin Mini ITX motherboards are mostly designed to use even less power than normal ITX boards.

• Also, the motherboard will be explicitly chosen according to its power draw

• The calculated TDP will be around 65 watts, which exactly fits a Sandy Bridge Core I5 laptop.

• A whole normal ITX system with a desktop Core I7 only uses 73 watts: http://blogs.tigarus.com/patcoola/2016/08/31/intel-i7-6700t-processor-review/

• The battery gauge will simply be a voltmeter, if there's a way to get that through an Arduino setup or even simpler, that'll do it.

The concept:

• I know laptops exists, but none of them have a 15" touch display with a Core I7 Quad Core CPU

• Only a very few laptop can transform into a true tablet, and they're getting "old" now (e.g. Acer R7). The deal is also to revive that concept.

• The custom laptop mainly cancels planned obsolescense. This concerns a bigger and removable/switchable battery pack, a bigger CPU heatsink -so it can stay passive longer (and use less power)- and also have an easier component upgrading system.

Solution

If your board does not already have a power converter from nominal 12v, you can use what's known as a DC-DC power supply. Some are available here:

http://www.mini-box.com/DC-DC

They are meant to convert generic nominal 12v power to consistent 12v, 5v, and 3.3v power for computers. Common applications are car-computers, where source voltage can be anywhere from 10-15VDC and be variable and somewhat noisy in normal conditions.

As you mentioned, some mini ITX boards already have this circuitry on the board itself and accept a single 12v input. If you're using one of those and concerned about the stability or input voltage being too high, you can use a simple 12v voltage regulator.

Comments

[Daniel B]

AA or even AAA are not able to properly support the required currents. Their capacity is also rather small. You’d need a humongous amount.

[X.LINK]

A Lenovo P50's battery is rated 7600mAh for a 11.4V output. So I'll likely need to correctly setup at least 30 AA batteries, which is not a problem in my situation. But if things gets too much, I may switch to at least six 18650 batteries combined with a 12V converter.

[ganesh]

THe battery gauge will be interesting. Battery voltage vs battery charge is not linear.

[X.LINK]

This is apparently possible: (is.gd/ITXPowerGauge) But there's still no instructions or hints on how to do it. I originally considered the power gauge as: "If this goes under let's say 11V instead of 12V, a shortage will come soon".

[Daniel B]

Yes, that’s 86 Wh. You’d need at least 340 AA (2.5 Wh) cells for that. Just short of 10 kg. Good luck with that. ;) As battery count increases, monitoring is also very important to ensure an even discharge state. Otherwise, polarity may reverse and fireworks will ensue. And yes, of course there are battery gauges for all sorts of batteries. The point is just: You need a specific one. Voltage will remain relatively constant and then suddenly drop a lot in a very short time.

[X.LINK]

34 would be more exact, I almost hanged myself when I saw 340 :D. So, if that's around 1Kg, this sounds perfect 8D

[Daniel B]

It's 10 in series: 1,2 V * 10 = 12 V (very optimistic assumption, given voltage drop). Then, you have one 2.5 Wh series that can provide maybe 5 A at best. So to get 86 Wh you just need to have a lot of those series in parallel.

[X.LINK]

The voltage drop is the main problem then, does a 12V/10amp power regulator (for later upgrades) is difficult to do ? Is it also small enough ? Also, I've heard that regulators may not be that efficient, so you'll end using more power than it should, is it true ?

[Sampo Sarrala - codidact.org]

18vdc battery pack regulated to 12vdc? something like m.linear.com/product/LT3724#overview

[Sampo Sarrala - codidact.org]

Theres also plug and play ic regulator packages out there, might be worth browsing through few ic mfg catalogs.

[X.LINK]

The input to the regulator is 12VDC and up to 10A. I just need something that will prevent vdrop and ensure a constant 12V output to the motherboard. However, the link you sent me shows something way more complicated that waht I'm intending to do.

[Admin]

@X.LINK hey there! is there any update on your thin mini itx project? I'm thinking on building a similar setup.

[X.LINK]

@Karapapas: The project's is on standby state since thin ITX is a dying platform. I'm thinking about switching to full mini-ITX motherboard; but there's some problems: No LVDS connector, thicker laptop, motherboards potentially drawing more power, etc

[Admin]

@X.LINK It's true, every major manufacturer with the exception of Asus and Asrock have abandoned the platform and every new platform is far from a a thin enough form factor to be considered a laptop.

[X.LINK]

Their OpenUPS is by far the closest thing to what I want to do (voltage regulator + battery charging + OS power gauge !). Unfortunately, it only supports up to six 18650 batteries while I will surely use even more of these cells (9 to 12) or at least 30 AA batteries :(