Hybrid Inverter

Costs

• $800 for 6kW [1].
• 10kW is $1400 [2]

But That is Ridiculous

If grid goes down, so does your solar power! That's not acceptable for critical operations during the day. There is a complex solution: essentially set up another off-grid inverter system that powers your on-grid inverter without grid. Ridiculous and expensive. [3] and [4]

Solution - OSE Hybrid Inverter System. No batteris, up when sun is up, no grid needed.

Disadvantage: up only when sun is out.

Advantage: no batteries needed. Switch back to grid as needed.

Key: have enough PV to run everything that you need, and to shut off loads via a smart controller. Using cheapo 63A automatic transfer switches with Arduino will work. Get out the CNC circuit mill and build circuits as needed.

Hybrid Inverters

• Have a small bat bank and can operate without grid. [5]
• Not clear how the solar mode operates - does it put out the full power of the panels?
• $1600 - hybrid 6kW solar inverter (450VDC input max)- does it work at full PV output without batteries? Does it work at full PV output when grid is down, and sun is available, on a small battery? [6]? Does it work at full PV output when grid is down and there is no battery? If this thing can work full PV output - with grid signal (not using grid) - then this meets our needs. Or, does it switch 100% to grid whenever it's overloaded
  • On-grid - it's not pass-through - max grid power it puts through is 6kW - [7].
    • This would be impractical for most homes if they are not energy-efficient smart homes. Does not leave chance of higher power use, such as heavy power tools
  • Hybrid inverter allows battery-only, grid-only, and solar only modes, but limit in all modes is 6kW:
• This inverter appears to be stackable, but requires grid + PV connections to make this happen - up to 9 inverters, 54kW. Each inverter connects to the same battery. For single unit use- battery can be avoided all together. This means that small buffer battery should also work for up to 54kW?

• There is a cheaper $1350 model, not split phase, but 2-stackable to split phase 240, and 3-stackable to 3 phase, and stackable up to 6 units - but input voltage is a bit lower at 250V [8]
• There are cheapo hybrid inverters on Ebay - $700 6kW - not stackable? Are they also PV-only capable without battery? [9]
• $700 6.2kW - no battery capable? Yes. Stackable?. Only 230 AC not split phase? [10]

Mode of Interest: As Much Solar as Possible, Tapping Grid Only to Top Off What is Needed

• This is called Inner Limiter, or Double Conversion. Inner limiter - say 3kW solar + 1 kW grid. Double conversion - same, but inverter transforms grid to DC first, before sending it out as AC. [https://diysolarforum.com/threads/hybrid-inverter-output-priority.25954/