Increase PV self consumption with AC300

Hi. I just purchased an AC300 B300 package… I live in Germany and while searching for a backup generator I found this system. I was not really keen on a diesel or propane powered generator and the Bluetii solar generator seems ideal. Time will tell. I hope for a small payback through increased self consumption of my rooftop PV system and critical power during blackouts.

I have a 3KW solar system already installed and plan on using the PV Inverter (SMA Sunny Boy SB3000 TLST) generated AC output to charge the AC300 during daylight hours via Time Control UPS mode. In winter it will need to charge from the grid for the most part. Another option to charge is to use the SMA Sunny Home Manager 2.0 to control a Fritzdect 201 smart AC outlet so only excess PV current would be used to charge the AC300 – except in Winter of course. Still waiting for a Sunny Home Manager though.

Direct PV DC connection during blackouts using a D300S dropdown and a relay/switch between the AC300 and Sunny Boy is theoretically possible, but complicated and expensive. I will see if I can fool the SMA inverter that grid power is available using AC300 output. The SMA inverter shutdowns in blackout to prevent grid feeding. I would need to insure isolation (island) from the grid with simultaneous AC300 and SMA operations. SMA sells a solution with new hybrid inverter and BYD batteries, but they are not available and expensive.

Average daily PV production is 8.5 KwH. Maximum 18 KwH. I sell about 5.2 KwH daily back to the grid @ $0.16. I purchase almost 8KwH daily at double the price.

I want to increase my self use from the current 32%. I plan on using the AC300 to power two or three critical circuits in the house continuously. Currently planned are the refrigerators on one circuit and the living room (TV, Internet) on another. I am measuring the average watts they consume now. Battery draw would only be in the evening and at night. I can shut off power to the refrigerators at night via Smart Outlet switch if needed for a couple hours.

The accessories from Bluetii -like the Sub Panel- are not available in Europe, so I will integrate three 15 amp circuits via a On – Off - Emer switch (40 amp) installed in the existing CB Panel for my critical circuits. I over-specced the switch in case I wanted to use it later to to switch between 3 phase grid and 3 x 1 phase generator for the entire house.

Any comments welcome.

Hi Wuastr,

I would not recommend to use the AC300 as a Grid-Simulator to get the SMA Solar Inverter to think the grid is available and beginn to deliver energy. This will probably damage the AC300.
Only some Backup inverters will “talk” with the solar inverter by slightly changing the frequency depending on the charge state of the battery and the load present due to the appliances in the house. This will tell the solar inverter to deliver more or less power depending on the needs.
Again, to my knowledge, this is something the AC300 does not support. Both, the backup inverter and the solar inverter need to support this feature of load modulation via frequency variation.
If you still want to try it out, I would recommend to do it when the SMA is delivering less than 3kW of power (low solar radiation) to make sure the AC300 can compete against the SMA. …and film the test so you can upload an interesting video for the community!
Hope this helps!

Thanks Sebastian. Good tip.
I do NOT want to return a defective unit. I will not try and trick the SMA inverter. Special case anyway.
I just had to return the AC300 and B300 due to 17 error code 0800 in 8 days with 300 watt load. Twice a day.
Don’t want to go through that Horror again with Bluetti service in Germany. Actually I ordered from a third party so everything was relayed with delays and misunderstandings. Add the overwhelmed customer service today in Germany with anything related to PV. Apparently Bluetti EU didn’t get the 0800 error code memo and upgrade existing inventory. They delayed a week with requests for **Videos ** of an error code. At least I think that is what they wanted. They just said send a video to my store without expanding on what they wanted to see.To get an explanation would have cost another week.

If it wasn’t for the better AC300 features ( two MPPT inputs, priority choice of charging input, no loud fan running with minimal load, no chattering relays at low light PV input) I would have turned to EcoFlow Delta Plus.

In the meantime I installed two dedicated 370 watt modules oriented east west on my flat carport roof with 10% angle. I ran two cables to take advantage of the two tracker inputs. Should result in a 400 to 500 watt input most of the day to recharge.

5 days after I ordered the first units (that failed) they went on Sale here with 10% discount. In Germany you have 14 days to return without question. I did and will now reorder. See what happens.

I‘m in Germany as well, had no issues so far… knocking on wood!
Sounds like you had some trouble already…
I also have a Grid connected PV at home. I just used mc4 connectors on the DC cables coming from the panels to be able to connect them to the D300S (BLUETTI PV drop down module) and then to the AC300. Works pretty good with high efficiency, but my testing is still ongoing.

Just ordered a replacement system again AC300 B300. Couldn’t find anything that does what it does except maybe the EP500Pro which is not readily available. I like the modular system and easier to return if needed.
I started by looking for a backup gas generator and liked the lack of gas and ability to actually increase my self consumption. It may be possible that my first plug in which tripped the CB for the charging circuit may have affected the A300 negatively. Who knows.
I am curious if with my east west panels it would be better to use one or two MPPT trackers. With two panels in series you have a higher input voltage for longer time.

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