48v to 12 v buck converter to run 12 v inverter to reduce high standby power consumption of all-in-one

[james1]

Hi. I want to use an all-in-one solar charger/inverter for a 48 volt battery. However, the standby power consumption of its inverter is 65 watts. So my plan is to only turn on the all-in-one inverter when I run a large device like an air conditioner (the only reason I am upgrading my system). But for other times, like winter when I experience 4 or 5 days or more extreme overcast skies, I want to connect a 48 v to 12 v buck converter to the 48 volt battery and connect the buck converter to a low consumption 12 v 400 watt inverter(will usually just run aprox 30 watts).
(It seems 48 volt small wattage inverters are extremely rare)
So my battery power should last much longer.
Can a buck converter be used to power a small inverter in this manner? Does buck converter have a high standby consumption which would negate the power saved? Thanks for your input.

 

[BentleyJ]

Does buck converter have a high standby consumption which would negate the power saved?

You have answered your own question. Buck converters have finned aluminum enclosures or large heat sinks to dissipate heat losses. Why not take the price of the 12V inverter and buck converter, roll that into a higher quality 48V inverter with lower stand by losses.

 

[chilly2]

A company called Daygreen sell one that'll handle 60A (720W). There may well be others.

36V 48V to 12V 13.8V 60A 828W DC DC STEP DOWN CONVERTER VOLTAGE REGULATOR

Wide input voltage from 30 to 60V Work for appliances from 0AMP to 60AMP automatically 100% full rated power 100% full stable output current 100% burn-in test High-efficiency up to 95% Waterproof sealed Cooling by free air convection Surface mountable 3-year warranty Over-current, over-voltage...

daygreen.com

 

[sunshine_eggo]

Victron Phoenix line has a variety of 48V low power inverters:

https://www.victronenergy.com/upload/documents/Datasheet-Inverter-VE.Direct-250VA-1200VA-EN.pdf

Price list:

https://www.victronenergy.com/media/pricelist/Pricelist_Victron_EURO_C_2024-Q1.pdf

Models on page 4:



Very low idle consumption

Inverters are most efficient at around 30% rated output, so it's a balance of sizing for the loads vs. idle consumption.

I also agree that you should invest in higher quality equipment rather than cobbling together a frankensystem.

My 2X Victron 48/5kVA Quattros use 54W idle combined.

The Multiplus-II line is further optimized for lower consumption. IIRC, their 48/3kVA unit is 11W.

 

[james1]

You have answered your own question. Buck converters have finned aluminum enclosures or large heat sinks to dissipate heat losses. Why not take the price of the 12V inverter and buck converter, roll that into a higher quality 48V inverter with lower stand by losses.

Thank you. Sounds like the correct approach.

 

[james1]

A company called Daygreen sell one that'll handle 60A (720W). There may well be others.

36V 48V to 12V 13.8V 60A 828W DC DC STEP DOWN CONVERTER VOLTAGE REGULATOR

Wide input voltage from 30 to 60V Work for appliances from 0AMP to 60AMP automatically 100% full rated power 100% full stable output current 100% burn-in test High-efficiency up to 95% Waterproof sealed Cooling by free air convection Surface mountable 3-year warranty Over-current, over-voltage...

daygreen.com

Thank you. I'll check it out.

 

[james1]

Victron Phoenix line has a variety of 48V low power inverters:

https://www.victronenergy.com/upload/documents/Datasheet-Inverter-VE.Direct-250VA-1200VA-EN.pdf

Price list:

https://www.victronenergy.com/media/pricelist/Pricelist_Victron_EURO_C_2024-Q1.pdf

Models on page 4:

View attachment 193893

Very low idle consumption

Inverters are most efficient at around 30% rated output, so it's a balance of sizing for the loads vs. idle consumption.

I also agree that you should invest in higher quality equipment rather than cobbling together a frankensystem.

My 2X Victron 48/5kVA Quattros use 54W idle combined.

The Multiplus-II line is further optimized for lower consumption. IIRC, their 48/3kVA unit is 11W.

Wow. Just what I was looking for. Thank you.
And thanks to all of you for helping people out.

 

[Lt.Dan]

I too recommend just investing in a higher quality 48v inverter, the Victron lineup is really amazing with their low idle consumption.

 

[xy74]

Morningstar SureSine 150W Inverter With Hard-Wired Output

Morningstar SureSine 150W Pure Sine Wave Inverter With Hard-Wired Output. Available In 12V, 24V, And 48V Models.

www.solar-electric.com

Uses 2.6W with the AC output on.

 

[Lt.Dan]

Morningstar SureSine 150W Inverter With Hard-Wired Output

Morningstar SureSine 150W Pure Sine Wave Inverter With Hard-Wired Output. Available In 12V, 24V, And 48V Models.

www.solar-electric.com

Uses 2.6W with the AC output on.

Looking at the spec sheet, even the 300w model is only 3.9w.

 

[sunshine_eggo]

It's a rare day when I get to say Victron is the cheaper option...

(but the zero load is notably higher... but still low)