4.6 kW Goodwe with backed up and non-backed up circuits.
Now, this morning the grid is on, the sun is shining, demand is currently 3.17 kW and everything sails along nicely. The bulk of that demand is on the non-backed up circuits.
When does the 4.6 kW limit kick in? Does that apply to total load, or to demand on the backed up circuits?
My guess is that it’s total load, and when the grid goes down then the inverter sheds the non-backed up circuits which will reduce the load.
Which means I can only ever draw 4.6 kW in my house. Which means the guest geyser (which I am testing today) is only useable as long as nobody wants to use the kettle or the microwave.
20A on the backup side. The non-essentials don’t go through the inverter, so they are unlimited. (But the inverter can only assist them up to 4600W for the total backup+non-essential)
If your panels can max out the inverter, and your non-backup side goes lets say up to 10kW. The inverter will send as much as it can to the non-backup side.
eg.
Panels can max out the 4.6kW on panels, backup use lets say 1kW, and non-backup is at 10kW, so total should be 11kW. The inverter will send 1kW to backup and 3.6kW to non-backup, and the non-backup will then get the remaining 6.4kW from the grid.
Nothing will be sent to battery for charging, theoretically, because the load is taking up all the generation. However, in practice, the mppt can generate a bit more than 4.6kW. 4.6kW is the invertion limit. Then a bit more can be used from panels to do some battery charging. So it is not uncommon to see panel/generation going over 4.6kW. I have personally seen it go just over 5.5kW if there is max invertion used and battery can take a charge.
Yes, the MPPTs can go up to 6.4kW. In that case only 4.6kW can go to AC, the rest will go to the battery (if it can take charge). But it can only do that if the backup+non-essentials use less than 4.6kW. If the total load goes over 4.6kW, it won’t charge the battery and will again cap at 4.6kW.
Not really (it’s the geyser that gets it from the grid)
A better way of thinking about it is that everything on the non-essential side is only connected to the grid. What the inverter does is to export all the excess it has. This offsets what is used from the grid. It can do this because it knows what you are using from the grid because there is a CT to measure.
In your case it’s slightly different because you can export, so the inverter will always export all the excess (up to the limit if there is a limit set). But when solar is unavailable it will export from the battery to try and match your use on non-essentials.
Without reading this in too much detail, the inverters most commonly used by people here are grid-interactive. While connected to the grid, all loads (whether on the input or output) essentially run from grid power, and the inverter itself acts like a grid-tied PV-inverter which just offsets the load by as much as it can, using either solar or battery. If you have more loads, nothing trips, nothing switches off… the remainder just comes from the grid.
If the grid fails, then the picture changes. If the output loads exceed the maximum capacity, it overloads and switches off.
Most of that is true, but the backup side is connected to the grid via a relay or something else that would have a limit too. So I dont think the backup side can use unlimited amounts of power even while connected to the grid.
Pretty certain, my goodwe es 4.6kW inverter reboot (basically trip the backup side) if the backup side exceed 4.6kW for longer than 10 seconds, regardless of whether the grid is available or not.
True. In my experience this relay is sized larger than the inverter though, so that for many people it will translate into “as much as you want as long as the grid is up”. For the most popular Victron unit (the 5kVA), the transfer switch is 50A, and most single-phase houses have a 63A breaker. That’s close enough
I would expect it to only report such overload warnings when the grid is disconnected. Perhaps there should be a severity level below “warning”, under which such notifications should fall.
