How to: Run EP600 or similar parallel to balcony solar?!

Product Discussion BLUETTI EP Series
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Hello everyone!

Im thinking now for a long time to install the EP600 or a similar System into house. One of the things that need to be solved befoure i can install such a system is: What does my on-grid balcony Solarsystem do, when the grid is failing and i have a EP600 installed?

You might think this is not a big deal right? But there are some things where no one thing about it. In this article i wanna show you quick the problem that is present and how i think im gonna solve it.

So whats the problem? - First you need to understand how “balcony solar” works. Mostly theese tiny Solar Systems have one or two panels which are connected to a grid inverter. It converts the DC from the Solarpanels to AC for the main house circuit, so every device can in my household can use this energy.

The output is capped at 600W. It doesnt matter how much energy i consume at this moment. When the panels deliever full 600W, i also have 600W “free” energy that i can use in the house. Everything i dont use at the time will be exported to the public grid.

The Inverter works as long it has 230V 50Hz, when one of the values doesnt match, it shut down. So far so great.

If im now install a EP600 System and the public frid fails, the EP600 will power the whole house. For the Grid inverter nothing changes in this case because EP600 still deliever the 230V 50Hz thats needed to run the Grid inverter. Since there is no public grid, the energy i dont consume cant be exported. The overflow of energy may find his way into an Output of the EP600 and destroy the unit.

Like the same a AC Inverter would die if you dont consume energy from DC to AC and instead try to charge a battery from AC to DC.

So we need a value that indicates that the public grid is faling. The solution i would build is simple but effective. I do have a lot of theese tasmota wifi plugs here, where you can turn on and off theese plugs via HomeAssistant if a condition is meet. So just buy one of theese plugs and when grid is not 230V 50Hz anymore, turn it off.

I have installed a sensor on my power meter which reads it values every 2 seconds. So as soon the grid fails, the plug will turn off after 2 seconds.

What do you guys think of this solution? Do you ever think about something like this? Would love to hear other opinions from the Community!

Also feel free to ask any question related to this :slight_smile:

greetings

Erik

PS: Thats the plugs im talking about: https://amzn.to/3Pdoft9

1 Like
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Hmm, an interesting question, to combine a balcony PV with EP600.
I think, the main question should be, how robust is the backup inverter in the EP600? If it is constructed in the same way as the grid inverter, it should not matter whether we load to grid, or get the power from grid.

But we do not know if it is the same inverter on backup side, that could also handle overloading in home energy because we generate more power via PV, than we consume ourselves.
Some micro inverters for balcony PV are able to work in “Zero Export Control”. In this mode, we have a minimum of power from the PV-inverter, near to Zero. Maybe this would be more “confortable” to the backup-inverter in the EP600?

Same question would be, what if we use an electric motor that works as a generator when switched off and thus feeds electricity into the grid? Would this also be danger to the EP600 inverter or can it handle this “reverse” direction of power INTO the inverter?
What will happen with the inverter? Would it itself switch of, or work like the grid inverter and push this extra power back to batery?

An additional mention to this question. If I remember me right, BLUETTI asked me, before installing the EP600, if I would use it in “island operation”. What about this mode? In island operation we use only the backup inverter and for thus, the inverter should also handle a reverse power. Maybe I’m wrong, but I do not know it better …

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Hi @SigiKa

Thanks for your comment on this!

The real problem you facing, when run in the same circuit is that the EP600 Output is not designed to take input. If you have more PV production than you can consume, this is a problem. Inout is only connected to PV or Grid. The House Circuit “Backup” is only a output, it cant charge via Backup.

The same for island operation. When the grid fails your EP600 works as a island system because it dont have any connection to the grid.

And sure, you can throttle the output of the balcony inverter, but i dont want to have this all the time. right?. With a on-grid EP600 i doesnt even notice when the grid fails, so i cant take any actions by myself and within seconds.

Maybe i get something wrong too, but as i see it right know, working together in the same circuit is really difficult.

greetings
Erik