amps confusion for synology ds218+ ?

[the_doc735]

On the synology website it says for accessing the data files that it requires 17.23W (Access)  ...but they supply a 12v/5a PSU = 60W!

 

So, would I really need a 60W LPSU for this device*, OR would a 12v/1.5a = 18W - lpsu be powerful enough?

 

NB: requires only 5.4W (HDD Hibernation)!

*(or was it a 'costing' decision/exercise?)

 

Cheers!

[DuckToller]

Salut,

you may take into account the requirement for the hard disks, when active ...
https://us.hardware.info/reviews/7265/13/nas-hdd-review-18-models-compared-power-consumption
cheers, DT

[the_doc735]

17 hours ago, DuckToller said:

Salut,

you may take into account the requirement for the hard disks, when active ...
https://us.hardware.info/reviews/7265/13/nas-hdd-review-18-models-compared-power-consumption
cheers, DT

these are: Kingston A400 240GB SSD (2x) ....

 

[the_doc735]

even if I double that for 'headroom' (17.23W (Access) about 1.5 amps, it's still only 3 amps = 36 watts!

That's what makes me think the psu of 5 amps by synology is a costing measure rather than a technical one? i.e. they simply supplied that as it was the best value (£) item for them in the production run and made better economic sense?

If that's the case(?) I would have thought a 3 amps psu would be sufficient?

[the_bat]

Presumably the power supply is sized to cover the maximum load if the NAS is fully loaded with high capacity hard disks, with a safety factor, and some economies from only using one size across multiple devices. 

 

Your use case case might (but might not) allow the use of a lower rated power supply but you couldn’t expect any support in the event of problems. 

[the_doc735]

1 hour ago, the_bat said:

Presumably the power supply is sized to cover the maximum load if the NAS is fully loaded with high capacity hard disks, with a safety factor, and some economies from only using one size across multiple devices. 

 

Your use case case might (but might not) allow the use of a lower rated power supply but you couldn’t expect any support in the event of problems. 

I've just heard from them and they have said that the decision to include a 12v / 5a PSU WAS NOT based on anything technical and could be lower, but that they had other priorities for choosing that PSU, they didn't say what those priorities were.

[Dan Gravell]

Bear in mind the PSU can modulate, so you're not drawing a constant 60W.

 

Typically in desktop computers you spec a PSU which is in excess of the demands of the system. Then, ideally, purchase a high quality PSU which is able to modulate the best. There are various certifications for this.

[bobfa]

On 1/14/2019 at 12:42 PM, the_doc735 said:

I've just heard from them and they have said that the decision to include a 12v / 5a PSU WAS NOT based on anything technical and could be lower, but that they had other priorities for choosing that PSU, they didn't say what those priorities were.

Priority may just cost of inventory.  Buy the same PS for all the models that can use it.  KISS inventory. 

[the_doc735]

22 minutes ago, bobfa said:

Priority may just cost of inventory.  Buy the same PS for all the models that can use it.  KISS inventory. 

+1