H2 Power Supply question

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jkarlmen
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H2 Power Supply question

Unread post by jkarlmen » Wed Jun 26, 2019 1:57 pm

Hi,

I'm considering purchasing the H2 as a mini home server (less power hungry than running my desktop 24/7). I know it doesn't come with a power supply but I've found a15V/5A and a 19V/3.95A (both 75W) laptop power supply that should work in theory. I know the specs say that it can handle 14 - 20V and supposedly up to 60W and their own power supply is a 60W 15V/4A unit.

1) Does the wattage matter? As long as it's more than it needs and the correct voltage, the H2 should just take what it needs, right? Kind of like how if I charge my Bluetooth headphones with my iPad charger, the headphones will take the .5Amps they need out of the 2.1A.

2) Based on that, does it matter that the 15V charger is a higher current?

3) Is there an advantage to using a higher voltage? i.e. 15V vs 19V? or is lower better/does not matter.

Here is an example of what I am looking at:

15V Power supply: https://www.ebay.com/itm/75W-15V-5A-AC- ... SwEARbF4M3

19V Power Supply: https://www.ebay.com/itm/19V-3-95A-75W- ... SwSOlcwqXF

Thanks

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mad_ady
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Re: H2 Power Supply question

Unread post by mad_ady » Wed Jun 26, 2019 2:54 pm

1. You are correct, the load draws what it needs.
2. Simple physics: Power = Voltage * Current. Lower the voltage and you need to increase the current to provide the same power.
3. It shouldn't matter. Internally the H2 has a step-down convertor that lowers and stabilizes input voltage to 12V. You'd need to know efficiencies figures for your supplies to see which one wastes less power. Also the dc-dc convertor has an efficiency curve which I don't know - maybe @odroid can tell you which input is more efficient,
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jkarlmen (Thu Jun 27, 2019 3:04 am)

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Re: H2 Power Supply question

Unread post by odroid » Wed Jun 26, 2019 4:03 pm

There is no significant difference between 15V and 19V.
Just use a well-regulated power source.
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jkarlmen (Thu Jun 27, 2019 3:04 am)

jkarlmen
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Re: H2 Power Supply question

Unread post by jkarlmen » Thu Jun 27, 2019 2:14 am

Thanks for the help!

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