Finding highest efficiency ac to dc and dc to dc converters

[Scph9002]

Do you guys have any charts/numbers real world test of the efficiencies of isolated dc to dc, ac to dc and dc to ac converters with efficiencies above 95%?


During winter with close to no sun I recharge my battery bank at night when electricity sometimes can be 5x cheaper and use it during day.
Mostly for fun, saving some money is ofc a plus.

Therefor having chargers and inverters with highest possible efficiency is paramount.

I find it really hard getting real non inflated efficiency numbers from product pages and sometimes no numbers are given at all.

Right now I use this charger

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It has a claimed efficiency of 93% from manufacturer in china and from American resellers like signaturesolar 95%.
I asked signaturesolar about their chargers efficiency and if they actually tested it. They said yes and linked a video showing it working submerged (it is ip67 rated) in water and measured the dc wire with an clamp meter... only. *facepalm*

Real tested efficiency is 89.5% converting 230v ac to 54v dc 40 amp

I use an smaller 30amp epever ssc as a dc to dc converter between my 48v bank to another 12v bank.
Claimed 98% efficiency but real efficiency is 94% converting 52v dc to 13v dc 30 amp

 

[newbostonconst]

Need to list exact thing you need...Like a need to convert 48vdc to 240vac at this many kW.....

 

[Dzl]

I believe Victron has a couple DC-DC converters that touch 95% or a bit higher on paper. And they tend to be a somewhat conservative company when it comes to spec's.

I have not seen any off-grid inverters above 95% to the best of my recollection, not sure exactly what you are looking for in terms of an inverter.

AC to DC conversion (not something I've paid much attention to) seems like its usually less efficient from what I've observerved inverter-charger efficiency is usually lower for charging.

And as Newboston said, the voltages you are converting to/from and the size of the load matter.

 

[Scph9002]

Need to list exact thing you need...Like a need to convert 48vdc to 240vac at this many kW.....

If you know any product you have tested or you know have been properly tested by others just list them here. Chances are the manufacturer make different variations of same product that suits me (and others) specific needs

 

[Dzl]

If you know any product you have tested or you know have been properly tested by others just list them here. Chances are the manufacturer make different variations of same product that suits me (and others) specific needs

I think the point of their comment about listing specifics was not to provide a perfect match for you, it was recognition that specific efficiencies depend on the voltage in/out and the load. The same company can produce a bunch of similar devices but the efficiency of 12 to 48 conversion would differ from 48 to 24 conversion, and the same device could differ at low load vs high load.

 

[Dzl]

As an example, the Victron Multiplus-II 3000
has a maximum efficiency of:
93.9% @ 24V and 800W
95.5% @ 48V and 400W

But at both 24V and 48V drops down into the mid 80's at 3000W and falls off sharply below 200W

https://community.victronenergy.com/storage/attachments/21928-output-rating-operating-temperature-and-efficiency.pdf

Similarly a solar charge controller will be most efficient when difference between Voltage in and Voltage out are close.

 

[MattiFin]

AC to DC conversion (not something I've paid much attention to) seems like its usually less efficient from what I've observerved inverter-charger efficiency is usually lower for charging.

And as Newboston said, the voltages you are converting to/from and the size of the load matter.

manufacturers usually don’t pay that much attention to AC-DC efficiency as AC power is typically more abundant than battery power.

there is some really high efficiency telecom ac-dc supplies but they are not the cheapest option.
Eltek comes to my mind first, flatpak super-HE series with up to 97,8% efficiency:

https://www.eltek.com/globalassets/imported-documents/open/datasheet-flatpack2-48v-she-rectifiersv01.pdf