I'm trying to understand how the EG4 12kpv and 18kpv hybrid inverters work when connecting to both the solar panels and the grid. When the sun is shining and the solar panels are generating, say, 5000 watts, but my house is using 8000 watts continuously, can the inverter take 5000 watts from solar and make up the remaining 3000 watts from the grid at the same time? If that's possible, doesn't that undermine the purpose of a transfer switch, which is supposed to let only one power source through at a time? Also, how does this system prevent back feeding, or is that a given since it's grid-tied and sending power back to the utility company?
4 Answers
Just to add to that, the way the system senses the load is via CT connectors (current transformers). When everything is connected, the inverter tries to meet the demand using solar power first, and if that's not enough, it gets the rest from the grid. So in cases where there's a heavy load, like 18kw, the inverter will kick in with 12kw of solar and pull in 6kw from the grid. But when the grid goes down, it isolates itself automatically thanks to that transfer switch.
The 18kpv model has an interesting setup. When connected to the grid, it operates like a T joint where power can flow from either source depending on what's needed. So, if your load is higher than what the solar can provide, the inverter kicks in and pulls the difference from the grid. As for the transfer switch, it actually only activates during a grid outage, so during regular use, everything is interconnected just like you would expect from a hybrid system.
Yes, that's how the EG4 works! It can blend solar power and grid electricity seamlessly. Basically, if your solar panels are producing 5000 watts and your house is pulling 8000 watts, the inverter will use the solar energy first and pull the extra 3000 watts from the grid to keep everything powered up. It's designed that way so you don’t just rely on the grid. However, concerning the transfer switch, it's a bit misunderstood here—many people think they need it, but it’s really not required for hybrid setups like the EG4. Your inverter manages the power flow, so it keeps everything within safe limits without back feeding into the grid when it's not supposed to.
So, just to clarify, does that mean the inverter never lets excess power flow back to the grid unless it's set explicitly to export?
Exactly! It only exports if it's set up to do so and if you're generating more than you need.
I've had the 18kpv unit for a while now, and it's quite powerful! It has a 200amp pass-through from the grid. I originally had a smaller solar setup that I connected with the 18kpv. Now, I run my entire house mostly on solar with very little from the grid. It's flexible enough that I can charge my electric vehicles using solar energy without much hassle, and the control interface is pretty straightforward.
Got it! So during normal operation, the inverter just manages power without needing to switch things manually, right?