Efficiency gain going from Gold rated 120V to 240V?

[Archaea]

If a PSU is rated Gold at 120V will it increase several percent efficiency if plugged into 240V?

The question stems from some server power supplies I was reviewing that said 87% efficiency at 120V and 93% efficiency at 240V.

I tried to web search this question, but have come up empty. Does anyone know of a website that tests efficiency at both standards?

 

[Brian_B]

I don't know of a web site with specs

In general, for a given amount of power the higher the voltage, the lower the amps. Amps are what cause heat, and all heat is efficiency loss.

But that only applies to the AC side, once it's be stepped down and recitified, your stuck at ATX rail line voltage (12/5 VDC). Rectifiers also tend to be more efficient the higher the voltage difference between input and output, but, that has a lot to do with design and such.

So a higher voltage unit ~should~ be more efficient, but I couldn't say how much.

Mostly, I see people jumping to higher voltages when they need to pull more power out of a single socket - most wall outlets are limited to 15 or 20 amps. At 120V, that's roughly 1500W before you will trip the circuit, but at 220V that's closer to 3kW.

 

[Tsumi]

If 80+ ratings are any indicator, it is at minimum 3% more efficient.

 

[Speedeu4ia]

If a PSU is rated Gold at 120V will it increase several percent efficiency if plugged into 240V?

The question stems from some server power supplies I was reviewing that said 87% efficiency at 120V and 93% efficiency at 240V.

I tried to web search this question, but have come up empty. Does anyone know of a website that tests efficiency at both standards?

Jo

If 80+ ratings are any indicator, it is at minimum 3% more efficient.

This is exactly what I found posted elsewhere. I did see a graph somewhere maybe jonnyguru showing it also

 

[RedDwarf]

I read it was around a 2% increase. However the bigger the improvement the better for us in 220-240V countries. A 6 point improvement seems a lot.

 

[bigblueshock]

Yes, 240v generally will generally increase (even if its slight) over 120v.

Newer power supplies lessen this gap, but still 240v is more efficient.

Give thanks to the US of A for rebuilding all the European countries from the ground up after WW2 with 240V and leaving us with shitty 120V