Will an undersized garage power feed plus an off grid inverter power a bigger load?

[woodythegr8]

Here is my issue. I have a detached garage that solar was installed on years ago. My issue is the solar company didn't install a 100amp service as they were supposed to, it only has a 30 amp main breaker. This is not enough power to run things like a dust collector (3HP motor) and table saw at the same time. As it will be very expensive to have a new feed wire run to the garage, and I have plenty or unused room on the flat roof for more solar, I was considering an off grid system to power the garage and charge my car. Based on what I have read, two - EG4 6000XPs and a couple batteries would support the load. My question is: Where I have a 30 amp feed that I can also bring into the off grid inverter, will a single inverter likely be enough when combined with the existing feed? Or does "Passthrough" just mean if external power is available it uses just that?

 

[SparkyJJO]

Depends on the inverter. Some can supplement inverter output with grid input (mix them together to power a load larger than the inverter can do). Others simply pass through, which means exactly as it sounds - no inverter use, just passes whatever grid connection it has through to the load.

 

[Brucey]

Here is my issue. I have a detached garage that solar was installed on years ago. My issue is the solar company didn't install a 100amp service as they were supposed to, it only has a 30 amp main breaker. This is not enough power to run things like a dust collector (3HP motor) and table saw at the same time. As it will be very expensive to have a new feed wire run to the garage, and I have plenty or unused room on the flat roof for more solar, I was considering an off grid system to power the garage and charge my car. Based on what I have read, two - EG4 6000XPs and a couple batteries would support the load. My question is: Where I have a 30 amp feed that I can also bring into the off grid inverter, will a single inverter likely be enough when combined with the existing feed? Or does "Passthrough" just mean if external power is available it uses just that?

A Victron multiplus or Quattro will do what you are looking for with their power assist function

Victron Multiplus II Assisting

I installed the Multiplus II 2x120 in my Class A back in the fall and am coming off the first big trip with it. Couple comments: Super nice to be able to run a anything off the inverter. We even ran one AC unit at a marina for a couple hours. Inverter provided good power while Solar was...

diysolarforum.com

 

[BentleyJ]

Yes, passthrough with an off-grid inverter means exactly that. Either utility power is passing through OR the Inverter is producing power from the batteries and solar but not both at the same time.

Something like a Sol-Ark or Schnider inverter, both are UL1741SB compliant, will sync to the grid and can blend power. For example a Schneider XW Pro has a peak load shave feature where utility current could be limited to 24A and the inverter would supply the remainder up to the limit of the inverter.

 

[Brucey]

The 48/5000 should be good for 5kW of assist from the battery in addition to your AC input.

 

[BentleyJ]

Seems like the Victron is not a split phase USA inverter, only 1 Hot leg. Or did I miss something?

 

[Brucey]

Seems like the Victron is not a split phase USA inverter, only 1 Hot leg. Or did I miss something?

That's correct would need two paired up to get 120/240V.

 

[woodythegr8]

The 48/5000 should be good for 5kW of assist from the battery in addition to your AC input.

View attachment 199008View attachment 199009

Thanks for the help, I read more about the MultiPlus 120x2 and it seems like the version that supports 120/240 in the single unit would be perfect!

 

[Brucey]

Thanks for the help, I read more about the MultiPlus 120x2 and it seems like the version that supports 120/240 in the single unit would be perfect!

No that 120x2 doesn't do what you are thinking. It's designed for RVs using 30A/50A connections. It can pass thru 240V however without grid/generator input it will supply 120V to both legs of an RV panel for example.

Quattro-II 2x 120V - Victron Energy

Similar to the MultiPlus-II 2x120V, the Quattro-II 2x120V is a combined inverter and charger specifically designed for standard North American 50A...

www.victronenergy.com

 

[ricardocello]

the MultiPlus 120x2

The MultiPlus 120x2 passes through split phase 120/240V, but when inverting it still only does 120V.
It simply combines L1 and L2 when inverting, meaning 0V instead of 240V!
Victron really doesn’t do split phase well unless you buy two units.

 

[DIYrich]

I belive the 3kw eg4 inverter can supplement grid, whereas the 6k can't.

 

[Q-Dog]

Your "undersized" garage feed could charge about 3000 watts per hour into some batteries. If the inverter/batteries are big enough to run the loads, is passthrough really that important? Build a truly "off grid" system for the garage and use the 30 amp connection to charge batteries when the sun takes a vacation.