Need some help with portable monitor

SFF Scrub

Average Stuffer
Original poster
Aug 7, 2017
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So I'm having some difficulty "cementing" the portable monitors info. I'm sure someone is going to link that one really long thread, but I read through it and I'm just looking for a confirmation that I have it right.

So it seems to me that the only way to be portable is to either:
1. Plug in a usb-c through mobo
2. Plug in a monster of a batterypack
3. Plug into an outlet through ac-dc

Problems (Hopefully this is where I will be corrected)
1. Usb-c can be used for power, but if so must be used for graphics, thus invalidating any GPU use
2. The batterypack route is expensive and you'll probably need at least 2 $100 batterypacks for multi-hour use
3. ac-dc is taking up another outlet and adds wires

So from this the easy option would be to go ac-dc, but that's not really what I'm looking for.
This is for a S4m portable desktop btw

Edit: Additional question. Is taobao the only place to pick up a ~15" monitor that doesnt suck? Everything that Im seeing under 20" on whitelist sellers is garbage
 
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VegetableStu

Shrink Ray Wielder
Aug 18, 2016
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Is the context that of a portable USB-C display? I feel that current USB-C displays aren't designed with having power and signal on separate ports ._. (and no one has made a power-injected DP+USB to USB-C Cable *angry sigh*)
 

SFF Scrub

Average Stuffer
Original poster
Aug 7, 2017
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Yes, that is why option 1 sucks, unless I'm wrong. Secondary question: Do I have it correct that usb 2.0A can run 100W? The wiki page says so but I'm a little iffy on that
 

VegetableStu

Shrink Ray Wielder
Aug 18, 2016
1,949
2,619
depends on the power source I think. It inherited that spec when USB 3 came about, so one could design something around a 20A power draw

probably don't stray too far away from the power requirement of the display? I'm still new to electronics, and my current thinking is get the voltage right, the device will pull what it needs (please do correct me if I'm wrong O_O)
 

winterbladexx

Average Stuffer
Sep 30, 2017
76
34
My ideal portable monitor would be a Mini Displayport to Displayport for data and USB for power. Kinda like the iPad mod.
 

SFF Scrub

Average Stuffer
Original poster
Aug 7, 2017
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I'm re-purposing some dead laptops screens that are kinda old, I don't think they're even 1080p. Displayport would be wasted upon them
 

ChainedHope

Airflow Optimizer
Jun 5, 2016
306
459
For a battery pack you could use some chinese 18650's. They are relatively cheap ($1-2 each) and people use them to build power packs to run as reserves for solar and wind power attached to their houses and tiny homes. Should be doable to wire up a set of them to power a monitor for a few hours without breaking the bank.

Heres someone wiring a load of 18650s to replace a Tesla powerwall. You can use the same principle to get the right battery size for your needs.

 
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SFF Scrub

Average Stuffer
Original poster
Aug 7, 2017
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I don't have time to watch this right now, but I cant wait. This looks bad ass as fuck
 

SFF Scrub

Average Stuffer
Original poster
Aug 7, 2017
56
16
For a battery pack you could use some chinese 18650's. They are relatively cheap ($1-2 each) and people use them to build power packs to run as reserves for solar and wind power attached to their houses and tiny homes. Should be doable to wire up a set of them to power a monitor for a few hours without breaking the bank.

Heres someone wiring a load of 18650s to replace a Tesla powerwall. You can use the same principle to get the right battery size for your needs.

So I watched the video and I must say that I am kinda crazy about these batteries now, I always just assumed that batteries were super expensive and therefore impractical, but I guess I wasn't looking in the right spot. So if I have this right, for 12V / 20W / 6 hour lifespan. I'd just need to make a 4 by 4 with a column in series and the rows in parallel?
 

ChainedHope

Airflow Optimizer
Jun 5, 2016
306
459
You'll need to find the min and max voltage your screen will work at. In your configuration you are ranging 16.8v (at full charge) to 12v (at no charge). If you want to do it this way you need to down convert your 16.8v to your max voltage so you dont fry your driver board or LCD.

I'd recommend to do 3 in series to range between 12.6v and 9v and put those "rows" into parallel with other rows to increase your wattage. If the screen will do more than 12.6v without any issues then you dont need to worry about converting it and you're screen will simply not "turn on" if the batteries need charged. Most of the time when something requires 12V it will work fine between 12.5-9.6v before it has issues (at least thats my experience with small LCDs like the PSOne screen). Which yeah means you aren't getting the most out of your batteries but overdrawing them to 0% and overcharging to 100% is worse on them anyways and can affect their lifespan later down the line.

Here are a few more videos I know about that go into "DIY" battery packs and portable monitors.

Similar Project by DIY Perks:
Similar Project by GreatScott:
 

SFF Scrub

Average Stuffer
Original poster
Aug 7, 2017
56
16
You'll need to find the min and max voltage your screen will work at. In your configuration you are ranging 16.8v (at full charge) to 12v (at no charge). If you want to do it this way you need to down convert your 16.8v to your max voltage so you dont fry your driver board or LCD.

I'd recommend to do 3 in series to range between 12.6v and 9v and put those "rows" into parallel with other rows to increase your wattage. If the screen will do more than 12.6v without any issues then you dont need to worry about converting it and you're screen will simply not "turn on" if the batteries need charged. Most of the time when something requires 12V it will work fine between 12.5-9.6v before it has issues (at least thats my experience with small LCDs like the PSOne screen). Which yeah means you aren't getting the most out of your batteries but overdrawing them to 0% and overcharging to 100% is worse on them anyways and can affect their lifespan later down the line.

Here are a few more videos I know about that go into "DIY" battery packs and portable monitors.

Similar Project by DIY Perks:
Similar Project by GreatScott:
Thanks for your input. I actually bought a bunch of batteries after I watched the video I previously commented on, but it's the same thing that's being said here. Thanks!
 

SFF Scrub

Average Stuffer
Original poster
Aug 7, 2017
56
16
They already have the screens, no need for them to spend $260 on that when they can do it for much less and have already shown they want to diy it.
I may or may not have actually broken my screen while encasing a new encloser. So yeah, new screens for this guy :'(