Completed DIY "laptop" / portable PC

timginter

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Apr 21, 2019
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Big milestone - changed status to "Prototype"!

Monitor and the control board came - dug out my old 12v power adapter to test it - all working good:

And a bonus - looks like the controller board doesn't draw any power (or less than 0.1) when the HDMI cable is unplugged. I won't have to worry about draining the battery if I decide to wire screen directly to the power supply (shown draw is the same as when I tested just the 12v power supply):


Waiting for the cooling and a second-hand processor to make some progress with the hardware.
 
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ignsvn

By Toutatis!
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Apr 4, 2016
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Big milestone - changed status to "Prototype"!

Monitor and the control board came - dug out my old 12v power adapter to test it - all working good.

I put together the chassis and updated the design - there was quite a bit of flex on the longer edge of the bottom box. Doesn't actually look that bad, but I'll definitely have to find other hinges - these look horrible. They were the cheapest ones I could get in reasonable time for the prototype, though.

Just waiting for the cooling and a second-hand AMD A8-9600 to make some progress with the hardware.

All in all, I'm quite pleased, not too bad actually. I'll update this post with photos a bit later.

Glad to know you're making progress.

Here's a similar project that I hope can encourage you:

 

timginter

Cable-Tie Ninja
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Apr 21, 2019
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Glad to know you're making progress.

Here's a similar project that I hope can encourage you:

Thanks. Really cool project, very neat, especially the battery solution. Mine definitely won't look like that 😉 With RGB and all the bling bling being the craze, I don't think my pragmatic approach will be right up most people's street
 
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timginter

Cable-Tie Ninja
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Apr 21, 2019
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I put together the chassis - I marked the screws 1cm from each corner and roughly the hinges, all clamped for drilling (very high class setup, I know 😉):


There was quite a bit of flex on the longer edge of the bottom box, I updated the design and moved two of the standoffs from left-right to top-bottom (added them after I took the photos).

Doesn't actually look that bad, but I'll definitely have to find other hinges - these look horrible. They were the cheapest ones I could get in reasonable time for the prototype, though (my hand on the second photo for scale):


The bobbin mounts made quite good legs. Conical, or with rubber at the bottom would have been better, but I couldn't find any in M4 size so these will do:


All in all, I'm quite pleased, not too bad actually. I'm waiting for the nylon threaded studding - cut to around 35mm will connect both plates and let me adjust the height:
 
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timginter

Cable-Tie Ninja
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Apr 21, 2019
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Well, CES was a bit disappointing for desktop APU announcements... There are a few leaks for Ryzen 7 5700G, though, hopefully for Q2/early Q3 2021 if chip shortages have an impact? Fingers crossed.

I found an interesting 12v DIY UPS video - if I can use a similar circuit for 22.2v, I may not need the OpenUPS for a prototype or even the proper build. OpenUPS's wattage (19v 6A, 10A peak) may be a bit too close anyway.

I ordered a 6S 14A 22.2V 18650 BMS board. If I put something together myself I will be able to fit the batteries in the bottom box without changing the height. Capacity will be very limited without another set in parallel, but will be enough for some basic work and to keep the system up while moving to plug in somewhere else.

Not sure how it will be at an airport... probably not something I'll have to worry about for at least another half a year unfortunately, with how things are going in the UK
 
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timginter

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Duh! Just went through the wiring for the battery - HDPLEX DC power supply is 19v - won't be able to charge 6S with it without a 19-25v step-up between the power supply and the BMS!

I'll go with a 5S 20A BMS board instead - charging 5S with 19v should be OK and I shouldn't need any stepping. BMS will handle charging and balancing the batteries, and HDPLEX ATX PSU will buck/boost the voltage if coming from the batteries.

Also had a look at 18650 cells for a DIY pack - a 5S of good 18650 cells should be around 2cm high, but will cost around £30 anyway. Overlander 3350MAH 18.5V 5S 35C SUPERSPORT PRO LIPO BATTERY is just 27mm high, but quite expensive. ZIPPY Compact 4000mAh 5S1P 40C Lipo Pack or ZIPPY Compact 5000mAh 5S 25C Lipo Pack, or even Turnigy nano-tech 4000mah 5S 25~50C Lipo Pack w/XT-60 look really good. Might just solder connectors to the 5S 20A BMS - an XT-60 for positive/negative and a JST-XH for balancing? Plug n' play, replaceable battery solution? I could make the chassis a bit taller at the back (bottom box) to house the battery.

I can only hope someone with some electrical knowledge will call me out if I'm talking total nonsense 😉
 
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Choidebu

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Aug 16, 2017
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I was directed here since my spec fitted more a SFF than eGPU config... surprised how little activity there is on the forums.
Tell me about it.

It's basically dead. All peeps cared about is the next shiny case @Wahaha360 's bringing.

The forum turned into sff indiegogo basically.

Back to your project, it's intriguing - not my cup of tea I'll have to admit - personally I think forcing desktop parts into laptop formfactor is a bit much.

The electrical and battery part, however, always excites me. I'll be watching closely, with however little spare time I have these days.

Duh! Just went through the wiring for the battery - HDPLEX DC power supply is 19v - won't be able to charge 6S with it without a 19-25v step-up between the power supply and the BMS!

I'll go with a 5S 20A BMS board instead - charging 5S with 19v should be OK and I shouldn't need any stepping. BMS will handle charging and balancing the batteries, and HDPLEX ATX PSU will buck/boost the voltage if coming from the batteries.

Yep you ran into same problems I had with roadrunner.

Good news is, through my testing, hdplex dc-atx can go as low as 14V until it shuts off. And even go as high as 30V. So in our case 5S (15V to 21V) or 6S (18V to 25.2V) both fell right into its range.

And FYI since you don't use dGPU I recommend doing what I did: power your lcd controller board from the dc-atx's pcie power out (4 pin molex). It's 12V and GND only, with added bonus your board+lcd now turns on and off with the pc.

I use 24V supply from meanwell since I use 5S and don't want to add a boost circuit. In my case I have a ups board to handle charging and swapping input from wall to battery.

I'm not sold on your idea that the bms you linked will handle charging correctly, if at all. With Lithium battery as expensive as it is, I won't risk it.

If you don't want to tackle this atm I'd say just forgo charging in-the-device and go with minibox's Y-PWR to handle switching from psu to battery.
 

timginter

Cable-Tie Ninja
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Apr 21, 2019
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And FYI since you don't use dGPU I recommend doing what I did: power your lcd controller board from the dc-atx's pcie power out (4 pin molex). It's 12V and GND only, with added bonus your board+lcd now turns on and off with the pc.
Great tip, thanks! Did you make your own 4-pin to male jack cable?

I use 24V supply from meanwell since I use 5S and don't want to add a boost circuit. In my case I have a ups board to handle charging and swapping input from wall to battery.
Thanks! GST220A24-R7B is a bit more expensive in the UK than HDPLEX, but will work great.

What UPS board did you use?

I'm not sold on your idea that the bms you linked will handle charging correctly, if at all. With Lithium battery as expensive as it is, I won't risk it.
Do you think the BMS will not limit the charge current, and instead of the recommended 1A it will charge at whatever max amperage the PSU provides? I'd potentially need a DC-DC Regulator between the AC-DC PSU and BMS to limit current to 1A, but not between the BSM and ATX PSU?

If you don't want to tackle this atm I'd say just forgo charging in-the-device and go with minibox's Y-PWR to handle switching from psu to battery.
Thanks, but it would mean I'd need a separate charger and take the batteries out whenever I need to charge them. I'm not in a hurry to make it battery-powered
 

Choidebu

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Aug 16, 2017
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Great tip, thanks! Did you make your own 4-pin to male jack cable?
I did.

What UPS board did you use?

ups-0528-11 from AliExpress

Do you think the BMS will not limit the charge current, and instead of the recommended 1A it will charge at whatever max amperage the PSU provides?

No it won't. It'll shunt the current on overvoltage condition (bms with balance will do this for each series cell), protects against some more cases but it doesn't replace a charger.

Proper lithium charging is cc-cv method which you can't get with dc-dc regulator, only the cc (constant current) part.
 
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timginter

Cable-Tie Ninja
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ups-0528-11 from AliExpress
Thanks for the full name - I was looking for a "UPS board" or something similar earlier and couldn't find anything, that's why I thought of going OpenUPS or BMS route. Once you have the proper name, Google is indeed your friend 😉

Proper lithium charging is cc-cv method which you can't get with dc-dc regulator, only the cc (constant current) part.
Thanks for the explanation - really helps to visualise how it all works.

If I understand it correctly there are 2 rough ways of doing it, then:
  1. Code:
    AC-DC -- UPS -- ATX
     PSU      |     PSU
             BMS
              |
        5S BATTERY PACK
  2. Code:
    AC-DC -------------------- ATX
     PSU      |            |   PSU
           CONSTANT        |
           CURRENT         |
           ADJUSTABLE      |
           BUCK            |
           CONVERTER       |
           TO 1A           |
              |------?------
             BMS
              |
        5S BATTERY PACK

Second option more complicated + diodes preventing current going from the batteries back to the adjustable buck. Potentially more magic to prevent the bucked 1A current going along with unbucked current when AC-DC PSU is plugged in, if that's even an issue (marked with "?" above)? All in all, the UPS route seems to be much easier.

Realistically, all I need the battery for at this stage is to unplug the AC-DC PSU and plug in somewhere else without turning the PC off, so probably 150W max, definitely less if no heavy tasks are running while I unplug.

ups-0528-11 board is 15A max discharge - no problem even with 15v worse-case-scenario from 5S. Any high capacity cell with 15A+ max discharge should work, e.g. Samsung 30Q cells (high capacity, mid price), assuming 90% advertised capacity they should still have 2700mAh.

Discharge is a bigger problem with 5S1P:
  • recommended is 1C = 2.7A at 2700mAh,
  • 15A max = around 5.5C max discharge,
  • 1C discharge = 2.7A * 15-21V = 40-56.7W,
  • 150W discharge for 5S1P is around 3-4C - not ideal but still below max.
I'll just accept that cells will deteriorate - building a 5S4P would probably add more costs than savings over time. I can swap them if they lose too much capacity.

This turned into a really interesting project. With all the banggood / aliexpress / ebay reading I'm getting fluent in Chinglish - bonus!
 
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timginter

Cable-Tie Ninja
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Temp Ryzen 5 3500x CPU finally came! Time to test hardware!

Had to connect my GPU with some awkward cabling through eGPU adapter, but all worked in the end

Now waiting for GST220A24-R7B power brick, the UPS and BMS boards and a few connectors and cables - 4pin PCIe extension and DC jack to solder together for powering the monitor, some PCIe 8pin to 6+2pin extensions and PCIe 6pin to 6pin extensions to solder with 4 Pin DIN male and female plugs for easier connecting, a PCIe x16 extension/riser and probably some more stuff - I honestly lost count with the deliveries. I'll just update the parts list as I'm assembling/soldering stuff
 

ignsvn

By Toutatis!
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Apr 4, 2016
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Temp Ryzen 5 3500x CPU finally came! Time to test hardware!

Had to connect my GPU with some awkward cabling through eGPU adapter, but all worked in the end

Now waiting for GST220A24-R7B power brick, the UPS and BMS boards and a few connectors and cables - 4pin PCIe extension and DC jack to solder together for powering the monitor, some PCIe 8pin to 6+2pin extensions and PCIe 6pin to 6pin extensions to solder with 4 Pin DIN male and female plugs for easier connecting, a PCIe x16 extension/riser and probably some more stuff - I honestly lost count with the deliveries. I'll just update the parts list as I'm assembling/soldering stuff

I assume the PCB next to the LCD panel is the controller.

But what is that one next to the keyboard?
 

timginter

Cable-Tie Ninja
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Apr 21, 2019
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I assume the PCB next to the LCD panel is the controller.

But what is that one next to the keyboard?
Exactly, I had to connect the power to the GPU via the eGPU adapter to test everything, when I tried just the HDPLEX, 200W wasn't enough - fans would spin, but a few seconds later everything would restart.

I'm waiting for a 6-pin to 8pin PCIe cable to connect the DELL DA-2 directly to the GPU as per this nando4's thread - should be more tidy
 

REVOCCASES

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REVOCCASES
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Just in case nando4's solution doesn't work for you, maybe this could help to solve the power problem:


If you are good with DIY and want to keep the HDplex, this could also help instead:


I'm using this to run a simple eGPU with my NUC.
 
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timginter

Cable-Tie Ninja
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Apr 21, 2019
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Just in case nando4's solution doesn't work for you, maybe this could help to solve the power problem:


If you are good with DIY and want to keep the HDplex, this could also help instead:


I'm using this to run a simple eGPU with my NUC.
Nice, thanks. I'm planning to power the motherboard from a battery - I need a regulated ATX power supply for the battery voltage drop. That's a really neat solution, though, 200W mobo + 400W GPU is a perfect combination
 
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timginter

Cable-Tie Ninja
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Apr 21, 2019
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Checked today if I can squeeze in my GPU behind the screen, next to the motherboard - fits quite nicely:

The aluminium plates I ordered (on the photo above) are 15mm too short. When the prototype is done I'll order 400mm wide ones (as per list of parts) and everything will fit behind the plates.

All battery/UPS stuff later on will go in the bottom box, separate from the expensive hardware.

I updated the parts list and prices. Now more waiting... mainly for the PSU, connectors and extension cable for the GPU

EDIT:
Updated the TinkerCAD drawings for a rough layout. UPS, BMS and battery pack need moving, but waiting for delivery to see how best place them in the bottom box
 
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timginter

Cable-Tie Ninja
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Apr 21, 2019
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6pin to 8pin PCIe cables came! Couldn't wait and tested the rig with Dell DA-2 connected directly to the GPU - works like a charm.
I will use the prototype with the dGPU since the processor I'm using now doesn't have integrated graphics. When Cezanne desktop APUs come out I'll test performance in games - if the integrated graphics are powerful enough to only occasionally need a dGPU, I may change the final design to use an eGPU like a dock on my desk and make the rig much lighter. Modularity was the whole point so there's the option for either.
 
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ruleh

Trash Compacter
Jan 19, 2021
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Here is what I have for the battery configuration on a similar project.
Code:
AC-DC ----------------------->|------------------------DC-ATX
12.6V          |                             |
               |                             | (out: 12.3V)
             BOOST                         BUCK
             CONVERTER                     CONVERTER
               | (out: 25.3V 2-4A)           | (in: 18-35V)
               |                             |
               -------------------------------
               |
          MOSFET SWITCH
               |
              BMS
               |
           6S BATTERY

It switches automatically between ac and battery and charges the battery while ac is connected.
I have only tested this up to 70-80W since that is the max the system draws right now.
I should be able to test higher loads once new parts arrive.
low quality pictures following shortly, hopefully...
 

ruleh

Trash Compacter
Jan 19, 2021
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Since I can't edit my previous post, the pictures are here instead.
ac on:

battery power only: