Which is best for off-grid: LF versus 2xHF vs single-phase HF + AT ???

[fafrd]

For pure off-grid use (no connection to grid), I’m evaluating the different inverter architectures I am seeing and interested in any insights as to pros and cons of each and reasons to prefer one architecture over another:

LF: Conext SW is a good example of this architecture

2xHF (Split-phase): I’m sure there are a bunch of these but will choose the new EG4 6000EX as a good example of this architecture

Single-phase HF + AT: for a true off-grid setup, the AT would always be connected to no screwing around with switching it in and out or switching neutral-ground bond. There are too many 230/240VAC single-phase inverters to name but one of the many options from Growatt is probably as good as an example as any.

For simplicity, cost, and weight, the 2xHF split-phase inverters are very appealing so I’m interested to understand what drawbacks they may have versus the other two architectures…

 

[Ampster]

I’m interested to understand what drawbacks they may have versus the other two architectures

The only drawback from a HF inverter which I can think of is the issue of unbalanced loads. That is not an issue to me, since my 120 volt loads are not significant and easily balanced. My big loads are 240 volts. Also, I am on grid close to 100 percent of the time so my experience may not be relevant to the question in the title.

 

[SparkyJJO]

HF vs LF in one sense comes down to what your loads are. Heavy surge loads and that sort of thing is easier for LF inverters to handle than HF, generally speaking. Well designed HF can do it too but my preference is just the brute force capability of LF.

 

[fafrd]

The only drawback from a HF inverter which I can think of is the issue of unbalanced loads. That is not an issue to me, since my 120 volt loads are not significant and easily balanced. My big loads are 240 volts. Also, I am on grid close to 100 percent of the time so my experience may not be relevant to the question in the title.

Thanks. I should have clarified that the 2xHF inverters I am considering have double the output power of the LF options.

So for example, a 10kW 2x5kW HFx2 inverter versus a 4kW or 6kW LF inverter…

Cost-wise and weight-wise, the 2xLF options seem more than competitive with the LG options, so it’s secondary aspects such as surge capacity and/or unstable power / flickering LED lighting that I’m trying to understand more about…

 

[fafrd]

HF vs LF in one sense comes down to what your loads are. Heavy surge loads and that sort of thing is easier for LF inverters to handle than HF, generally speaking. Well designed HF can do it too but my preference is just the brute force capability of LF.

I’ve got several fridges / freezers that have some startup surge, but I’m looking at HF options that should have plenty of capacity to deliver that (5kW per leg).

I have no plans to run larger motors or power tools off of the off-grid power, so I don’t believe surge capacity is something I need to be concerned about (at least at the 5kW + 5kW level).