Let's build a laptop

#1

I don’t have Rock 5 yet, but going to buy one for my next custom keyboard project. However, I’m not experienced in electricity stuff, read a lot of comments about powering Rock 5B, but still have concerns.

What I try to achieve:
Put Rock 5B/A inside custom made keyboard, add power bank, LCD and I have a laptop. If I connect usb-c monitor - I would have second display, plus it would charge power bank (Same as it works with most usb-c laptops).

However I cannot think what powering options/adapter/etc to use, at least theoretically. Closest what I can think are these two options:

Option 1:
Rock 5B + good 60-100W usb-c PD power bank.
I connect power bank to usb-c port on Rock5B. To charge I connect charger to the power bank. If I want second display - HDMI is the only option (as usb-c is in use for power bank).
This option is simple and I bet it would work. However I won’t be able to connect usb-c monitor directly (without disconnecting powerbank cables).
Few question about this option:

  1. maybe I can workaround this option by putting some usb-c adapter in front, some female usb-c port to the case? I mean I connect usb-c monitor to “some adapter”, it splits my monitor signal to hdmi cable and one more usb-c to power my power bank?

Option 2:
If I connect power bank to GPIO power input (5V 3-4A as I read from comments) and leave usb-c for external monitor. Questions:
2) would this setup power my power bank once usb-c monitor is connected?
3) do you guys have any example of such UPS/battery/powerbank to connect to GPIO with 5V 3-4A? Anything like this would work?

Any other ideas welcome. And thanks for your time!

#3

What does it mean?..

#4

In other words, Rock 5B has only one USB-C port, that’s the problem. If I use it for my laptop battery (by using usb-c power bank) - I lose the port for external usb-c monitor. If I keep the usb-c port free for external monitor, then my only option for built-in battery is GPIO pins, where I have additional questions - will usb-c monitor re-charge battery on GPIO once connected? Also I guess GPIO is not enough to power Rock 5B with NVME…

#7

It seems like the 5V GPIO is on the VCC5V0_SYS net.

An alternative way would be look for the TYPEC_VIN net, i dont know whether there is a pin or pad exposed on the rock 5B on this net, if there is one, we might be able to solder a cable so that we can input <20V power.

#8

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I don’t see a pin/pad that expose that net, but i found that u might be able to solder a power source VIN between the two 1206 caps.

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I measured 20V Power In (when PD is connected) on this two caps, I think it might be possible to solder a wire at the middle of both cap as they are both VIN to the middle. (and your GND cable may goes to a GPIO GND Pin)

In that case you can supply anything from 5V upto 24V, u might be able to direct power the board with a few 18650s (as long as the output voltage is within 5-24V, that should be 2-5 pcs of 18650 in series)

Note: if u direct power it with 18650, you can not supply more than the total voltage of the 18650 to the usb-c port, to charge the 18650s via the usb-c port, you might want to see if there’s a module that will handle charging and power output on the same pin.

USB-C Power / 5 Volt
#9

maybe using an usb-c breakout would be possible instead of directly soldering the board?

#10

that should works, but what @smala wants seems to be having a fully functional usb-c port with dp and pd working, in that case the breakout board should also contains a usb-c female port that still connects to everything from the usb-c port to keep all functionality.

#11

yeah ideally that would be getting breakout board with both usb-c input and output connection that passthrough usb-c signal, and plug UPS in between on exposed power pins

I have some which expose all usb-c connections, but has only one usb-c port, which isn’t handy in that case

#12

Yeah, but directly soldering means only the plug UPS part is needed. which is a handy and low cost way as we dont need a breakout board.

#13

Well depends if you mind soldering things on board directly or not. In my case I would feel safer using breakout (even if you can also fry things if you don’t pay attention)
They are usually very cheap, just not sure if the right version exists

edit: seems like there is male to female:

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#14

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A cable like this might be useful, but not sure whether this cable expose all pins to work with DP.

And in my case, i prefer not exposing something externally since if the board is fitted into a case / enclosure it might not be a good idea to have to plug something outside the enclosure. I would prefer to have everything inside the enclosure.

#15

Not sure either, might give a try to see if it works
I’m also looking for a way to upgrade my board with UPS. I’m thinking leaving it in its original case (when i receive one) and plug custom UPS outside the case through usb-c

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#16

What UPS / Power module are you planning to use? Since i am also looking for a ups / module for my rock 5B as an NAS + Router.

#17

Haven’t looked that much yet, (so many things to look for that board: case, wifi card, 4G module, powering), but bit by bit getting there …
Probably something similar to what the author posted with 18650 cells.
First I thought plugin it on GPIO but seems like we can’t go up 5V and power might be limited that way… So might go for the usb-c hack we discussed.

Also looking to make it a router with 4G, plus all purpose server :slight_smile:

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#18

That one actually looks pretty good to me especially the 12V model as that UPS support automatic charging and powering seamlessly on the same port without requiring an external power source. However, if it can only handle 15W, it would not be sufficient for our rock 5B especially if u have an nvme ssd, or other pcie devices. And worth noting that the module seems to be a boost module, the 18650s are in parallel (3.7-4.2V).

I think that if there is a module which use a buck converter, it would usually handle more power, and this will allow the use of more cells in series.

Since our rock 5B is a larger form factor board than a raspberry pi, it might also be worth considering using 21700 cells for larger capacity.

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#19

The module mentioned on the first post seems only support 5V input for charging, but the usb-c pd will most likely activate the max voltage on the rock 5B which means the module will not be suitable.

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I found a module that output the battery voltage instead of using a buck or boost module, it can output upto 50W, it runs 3S battery. However, it seems only support input upto 15V. If the rock 5B negotiates a PD 20V, it might be possible that it can break the ups module.

#20

Using buck would decrease output voltage meaning you’ll need to put cells in series and you’ll also need to have BMS to balance charge.
In PD power bank, they usually put 2 big batteries in parallel, though they are often limited to 18W.

The module mentioned on the first post seems only support 5V input for charging, .

I guess this is expected voltage to charge 1S li-on batteries.

but the usb-c pd will most likely activate the max voltage on the rock 5B which means the module will not be suitable

quoting product page:

When the power supply is powered, the power supply directly supplies power to the load through the boost circuit, while charging the lithium battery. Once the power supply is cut off, the battery path is automatically started to supply power to the load through the boost circuit.

In both cases boost is used to scale voltage either from 5v ( if powered) or batterie voltage (around 3.7V), why do you see it as an issue?

The only downside I see is somewhat limited 15W output power but it shouldn’t be hard to find something delivering more power through boost converter. In e-cig it can go above 80W on single cell.

I found a module that output the battery voltage instead of using a buck or boost module, it can output upto 50W, it runs 3S battery. However, it seems only support input upto 15V. If the rock 5B negotiates a PD 20V, it might be possible that it can break the ups module.

That will be for sure more efficient not to use buck/boost, but voltage would be more around 9V at low charge and 12V a full charge? Usually PD only allows certain voltage to be negotiated, in that case I would presume it won"'t allow rock5B to negotiate 20V?

#21

When charging the battery, a buck module is needed to step down the PD’s 5-20V into 5V, the module only accepts 5V input max

#22

you mean at the input of UPS? my understanding is that it would work as follow:

  • plugged in:
    5V DC input => TP4056 Lithium Battery Charger Module => Lion battery => Boost converter => 12V PD output
  • unplugged:
    Lion battery => Boost converter => 12V PD output

I don’t think there is any PD involved in input, just regular DC voltage as per description:

USB port and standard 5V+and 5V - are external power supply ports. You can choose one of them

You can either plug regular usb cable (no PD) which is 5V by default, or plug 5V DC on + - terminal.
My guess is that 15W limitations either comes from USB power supply input not able to deliver more than 3A and/or boost converter not able to handle higher current

#23

Wow, great community! Thanks! Sad I’m not good enough to understand everything, but I got new ideas from the replies. I don’t feel confident to solder on the chip yet.

So if I buy:

One female (for usb-c monitor/power), and three male connector.

Also:

Power bank with two usb-c ports (both bi-direction).

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And make magic usb-c cable with power bank in between (I guess that’s what you suggested, but trying to make sure I understand correctly):
1 ) Usb-c female, to connect external power, usb-c monitor, or anything else
2-3) Most of the wires go straight to Rock 5, as it would with regular cable.
4) In between I put power bank with two usb-c PD ports, one port from female/monitor, another port to Rock5
5-6) only “power-related” wires go to power bank.

I’m not familiar with usb-c pd powering protocol yet and how all those wires work, but if someone can agree that theoretically it would work, I will study it.

Thank you all for your help!