Short:
PV: 30kW, Aurora PowerOne inverters (12.5; 10; 3; 3)
Battery: 15kWh netto, 3x 12s VW ID Block
Inverter: MultiPlus II 48/5000/70
I own an old Farmhouse with a PV installation from 2012. For a longer time i was looking for a environmental friendly solution to store my power to increase my self-sufficiency and to be more independent on a grid loss.
I like innovative systems like the hydrogen storage “Picea” from HPS or the Redox-Flow-Batteries. But at the end the efforts and costs where to high for my budget. So i concentrated on 2nd use.
First I started with used 7.2Ah lead acid block, that I got for free and connected 48 blocks to an array. But in the winter i could only use 20% of the capacity and it was very dangerous because regularly a block broke down and started to heat up so even one started to boil when i was not at home. So i was looking again for a more save system.
Now luckily i found one, who was selling used 44V Li-Ion blocks from VW ID cars. So i took 3 blocks and integrated them in my system. And it is nicely running since Feb. 2024.
Yes 44V is a bit low for the Multiplus 48V series but it is working fine.
My System:
AC-coupled to 30kW PV Aurora Inverters (PowerOne/ABB/Fimer)
1x MPII- 48V/5000
1x Cerbo-GX
3x LG-Chem 44V 6.85kWh 12S 6.85kWh 48V VW ID (MEB) Batteriemodul
3x JK-BMS
and a lot of connecting parts.
Bird view of my home:
First try, 12V 7.2Ah Array
The installation is moved in the barn.
You can see there is some place for additional MPII’s, maybe I will extend it to an 3P-system at some point. (The price of the multies crashed really down now!) But only my 9kW Sauna and my 21kW water heater are not covered right now and my 3P oven i can substitute with gas in case of a long time grid loss.
As main battery switch, I use an NH00 Holder with 100A fuse for each MPII.
Each battery block is fused with 70A on plus to the busbar.
For easy maintain I have connected an automatic transfer switch on the AC-Out-1.
Sight now I have an EM24 as grid meter but I would like to use the HAN interface of the PPS smart grid meter, but there for I need to have the interface available to my cerbo.
For battery monitor I chose the JK-BMS’s. They have an independent monitoring and can easily connected to the cerbo. A big benefit is that they have two temperature inputs that are compatible to the built-in sensors of the battery blocks. So, I have a redundant internal temperature of each block.
!CAUTION: The cell leads of the battery are fused with 700mA!
If you connect a balancer, you have to care for the maximum balance current.
The solar data I monitor with SolarView and in FHEM I have an EM24 bridge to feed the cerbo.
To also have enough energy in winter times I would like to install a 2.5kW wind turbine to compensate my 300-500W power gap. Maybe I will build my own Piggott turbine, at some point.
