Power an eGPU, Screen, and Lattepanda Delta via battery power??

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WIFI Darth Maul
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Sat Apr 04, 2020 6:40 am

I've been wanting to make a Lattepanda handheld gaming pc for quite a while now, and i was wondering if there was anyway that i could power an eGPU (i was going to use a gt 1030 low profile) via the lattepanda delta's motherboard by battery power using the 10 pin connector via LiPo cells. I was wondering if 6 LiPo cells would be sufficient for atleast 4hrs, or would i need a step up (boost) converter to power both the lattepanda delta, the gpu, and the screen (5 inch 800x480)?

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ccs_hello
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Sat Apr 04, 2020 5:06 pm

I doubt any of such configuration is possible.
The key issue is the "desktop GPU board" is typically 70W (a slightly higher end 150W) or so.
You'll have to find a power source that can supply such power for a period of your chosen time.

For example, a laptop LiPo pack may be rated at 74 Watt-Hour. Just to power a 70W GPU itself (not anything else), the battery will be completely drain in one hour.

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WIFI Darth Maul
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Sun Apr 05, 2020 12:03 am

It says that the GT 1030 uses between 32 to 34 Watts when gaming, do you think that will be enough power from the 6x 18650 cells to supply that even if it doesn't go the 4hr battery life i would want? Would i need a step up converter? Sorry I'm a complete noob when it comes to battery info

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ccs_hello
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Sun Apr 05, 2020 2:35 am

18650, on average, can offer about 8 Watt-hour each, from 100% full-charge to completely depleted.
6 pieces of 18650 will be 48 Watt-hour which can power a 34 Watt GPU board for a little bit more than one hour.
<-- this is not counting the LattePanda Alpha/Delta's own power consumption as well as other components.

If it is still what you want to do, you'll need a special synchronous step-up/step-down converter direct-hookup to the LiPo battery pack (after its battery protection circuit <-- must have it, no exceptions!!! ) to convert the 3S2P Li-Po pack
(12.6V when full and drain/battery protected mode at 10.8V) into 12V stable power to supply juice into into eGPU.

Also, I kind of do not like such design since the eGPU will always be powered while the LP Alpha/Delta might be shutdown. That is not optimal.

If I sound like Speaking Greek, this is not a project for you.

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WIFI Darth Maul
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Tue Apr 07, 2020 4:25 am

Nah i understand what you're saying, it's just room, heat, and money that's the problem. I'm not too familiar with step up converters, since I've never needed to use one. I was hoping the project would be under $500, but with the parts required it way be wayy over. The case for the device i was going to 3d print then polish with acetone. I also wanted it somewhat thin, atleast an inch or so. I was planning on having the eGPU run as a "plugged in" solution to be mainly used when plugged into an outlet, and the normal Lattepanda would run on the 6 cells when in battery mode, on the go. Would i have to get both a step up and step down converter, or would just a step up converter like this be suffice: https://www.ebay.com/itm/223548590990

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ccs_hello
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Tue Apr 07, 2020 3:07 pm

No, you'll need a 12V stabilizer such as this
https://www.amazon.com/dp/B07X9Y5MXT/re ... B06Y5JHZG2
or this one (even better efficiency)
LTC3780 Synchronous Buck-Boost module (search eBay, Amazon, etc.)
E.g., https://www.ebay.com/itm/LTC3780-DC5-32 ... 3944907334

It seems to me you are looking into battery as a power reservoir (i.e., poorman's UPS),
the required expertise is well beyond the scope of this forum.

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ccs_hello
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Wed Apr 08, 2020 1:21 am

I've thought it over again and felt rather uncomfortable set any design that is using
the 10-pin battery connector powered battery to power a power-hungry device such as eGPU.

Key is that the LP Alpha board is never designed to supply a lot of juice into the battery pack in the first place. It's charging capability is just for 3S Li-Po at no more than 2A (or 1.5A) charging current.

I.e., unless you charge the battery pack elsewhere (or charge w/ LP Alpha while no eGPU is plugged in)
and get it fully charged, and later get it ready to supply power to eGPU.
Such battery arrangement will drain very fast and LP Alpha's battery charging circuit will never catch up.

In analogy, it's like getting a Prius Prime (battery got wall AC charged overnight) to tow a 10,000 Lb trailer load. It does not make sense.

You can try other way, but using the battery pack on that 10-pin connector does not make sense.

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WIFI Darth Maul
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Wed Apr 08, 2020 6:55 am

Would using the usb-c port using a step up converter setup to power it make more sense?

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WIFI Darth Maul
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Wed Apr 08, 2020 6:58 am

I was planning on 3d printing a compartment to easy disconnect/reconnect the M.2 adapter for the eGPU, when needed anyways.

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ccs_hello
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Wed Apr 08, 2020 1:37 pm

Re: Would using the usb-c port using a step up converter setup to power it make more sense?

No, can't do. USB-C needs PD capability negotiation and it's just 15V 3A (45W) which barely can supply enough for LP Alpha's normal operations, not eGPU at all.

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