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Advice much appreciated - Small Grid System battery expansion

herold

New Member
Joined
Jan 24, 2025
Messages
2
Location
Denmark
Good evening.
I have a small grid tied +10years old Solar system in my house, consisting of 21Panels with 4.1kWp, and a Sunny Boy SB3600TL-21 Inverter.
I live in Denmark, and my system currently delivers power to my house if i use any, if not it is send back to the grid and sold.
The power i sell yields me next to absolutely nothing in money, and i currently buy the same amount of kWh every year as i am overproducing and selling.
My house runs at about 100w idle, and in Denmark when its Winter/Spring/Autumn the Sun is there when im at work, explaining why im "selling" more or less all the power i generate in Weekdays. I get home, fire up a lot of stuff and pay the price :) Common situation i guess.

Long story short.
Im looking to add a battery solution to my house, say a EG4 Wall mounted 14,3 kWh battery for instance.
I would like to be able to tie the battery into a setup where i use the battery (charged by solar) if battery power is available, and buy power from the grid if not.

I know these questions have been answered before, and do apologize if this is redundant but i sure do need guidance when it comes to the following.
Ive been reading, but wont propose what i think is a solution because my knowledge is next to none, and i get things mixed up - so heres the basics.

- Is it possible to add a battery and have my current setup manage it - that is charge the battery if solar is available, and have the house use battery power if available?
- If not, should i look at exchanging my current inverter, or add a extra inverter or other hardware to my system ?
- Last but not least, i would idealy love to have a system that i could build out in battery capacity to also charge a EV with (Not necessarily fully charging it).
Again with power from battery if available, if not from the grid.

Thanks in advance, and have a nice weekend :)
 
- Is it possible to add a battery and have my current setup manage it - that is charge the battery if solar is available, and have the house use battery power if available?
- If not, should i look at exchanging my current inverter, or add a extra inverter or other hardware to my system ?
- Last but not least, i would idealy love to have a system that i could build out in battery capacity to also charge a EV with (Not necessarily fully charging it).
Again with power from battery if available, if not from the grid.

Thanks in advance, and have a nice weekend :)
Assuming you were in the USA (don't know if the EG4's work in your country), the easy solution is to use an EG4 12kPV, 18kPV, or Gridboss/Flexboss21.
The Sunnyboy would be AC PV into the EG4.
Grid goes into the EG4
Main panel is connected to Load port of the EG4.

The system would allow you store power produced during the day, and use the power over night.

You still would have the problem of overproducing in the summer, and underproducing in the winter.
 
Assuming you were in the USA (don't know if the EG4's work in your country), the easy solution is to use an EG4 12kPV, 18kPV, or Gridboss/Flexboss21.
The Sunnyboy would be AC PV into the EG4.
Grid goes into the EG4
Main panel is connected to Load port of the EG4.

The system would allow you store power produced during the day, and use the power over night.

You still would have the problem of overproducing in the summer, and underproducing in the winter.
Thank you very much
 

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