Small battery inverter for on-grid AC home solution

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Simon2021

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Feb 7, 2021
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Hi there,

I am running just a small solar panel installation on my terrace and would like to add a battery pack. The idea is that I am measuring the total home consumption/production. This number I want to feed to the charger, which is plugged in a normal electrical plug (AC). The charger loads/unloads the battery witht the feeded data. It would be sufficient if the charger is just able to load/unload with a specific power load, p.ex. with 100 W. It does not have to adapt always to the exact current power.

Are there any charger/decharcher for 230V grid voltage and 48 V LiIon voltage on the market?
 
Simon2021 said:
Hi there,

I am running just a small solar panel installation on my terrace and would like to add a battery pack. The idea is that I am measuring the total home consumption/production. This number I want to feed to the charger, which is plugged in a normal electrical plug (AC). The charger loads/unloads the battery witht the feeded data. It would be sufficient if the charger is just able to load/unload with a specific power load, p.ex. with 100 W. It does not have to adapt always to the exact current power.

Are there any charger/decharcher for 230V grid voltage and 48 V LiIon voltage on the market?
Click to expand...

I am doing exactly that in my AC (coupled) - Powerwall project. Chargers for 48V are on the market in masses (low to high power outputs). You need to look for e-bike chargers or small vehicle chargers. As inverter it will be then the Sun1000GTIL with zero-export feature for a small system.
For export power measurement on 1 phase only, I would recommend to use the SDM120 meter, read out via ModBus...

 
Many thanks! I found some info about the inverter on aliexpress. I am not quite sure how to limit it. How does the data interface work?
An do you now what the inverter itself consumes?
 
Simon2021 said:
Many thanks! I found some info about the inverter on aliexpress. I am not quite sure how to limit it. How does the data interface work?
An do you now what the inverter itself consumes?
Click to expand...

Just went to check the idle consumption of my Sun2000GTIL (1000GTIL will be similar), and A-meter showed 0.31A AC which equals to 70W. DC side disconnected. This inverter is powered from the AC side, means from your grid, whenever you are not generating.
Limiting is easy and automatic. You put the CT over your incoming line, and it will zero out the import up to its maximum power output, or to a smaller value if you have set so. UI is the screen with a few buttons. Relatively easy to set, else not much to do. Just feed it with DC from your panels or battery...
 
Puh so for small setups like I planned to, this is not reasonable. The idle consumption is much too high with 70 W. Something like 10 W or less would be reasonable to think about it. 70 W is even more than my parents hybrid inverter with 5.5 kW uses.
 
Simon2021 said:
Puh so for small setups like I planned to, this is not reasonable. The idle consumption is much too high with 70 W. Something like 10 W or less would be reasonable to think about it. 70 W is even more than my parents hybrid inverter with 5.5 kW uses.
Click to expand...

I agree that 70W is a lot. How much power are you planning to inject to your AC? I do not think there is any inverters with 10W standby power, and you would as well have efficiency losses during inverting (typically 3%). And then the round trip efficiency from the battery side. The smaller the system in general, the bigger the inefficiencies.
 
Correct. I think 100 W injection would be sufficient. I also do not need to have it variable between 0-1000W. So if I am able to tell the inverter to inject 100 W fixed in specific scenarios, that would be ok. So not always 100 W, but when I tell it to start, it could do it until I say stop.
 
Roland W said:
Something like this maybe:

THB 2,290.56 20%OFF | 500W Micro Grid tie inverter for 12V 24V 36V 48V battery discharge adjustable output power solar panel grid tie inverter
a.aliexpress.com

70.4US $ 20% OFF|500W Micro Grid tie inverter for 12V 24V 36V 48V battery discharge adjustable output power solar panel grid tie inverter|Inverters & Converters| - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
a.aliexpress.com a.aliexpress.com

Output can be adjusted and runs from a battery (up to 350W/89% efficient) as well...
Click to expand...

Interessantes Teil, aber nicht für LiIon geeignet.
 
Roland: What is your opinion of the reliability of the AC chargers you are using? I have seen those for sale, and was considering buying one. Thank you for any input.
 
prepared1 said:
Roland: What is your opinion of the reliability of the AC chargers you are using? I have seen those for sale, and was considering buying one. Thank you for any input.
Click to expand...
Am very satisfied with them. Very simple to use, just power them on by plugging into a socket (if you don't cut them up as I did :) ). But there is nothing to set. Charging voltage and current is fixed as by your choice. Over all a solid build quality. My chargers have already pumped almost 4 MWhs into the pack, running up to 6 hrs a day. No issues or whatsoever...
 
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