Why an ESS?
With 4 PV systems installed, we feed back to the grid around 5500kWh in a year. We like to use this ourselves.
What did we build?
The main used components are:
- 3x Multiplus-II 48/5000/70-50
- Cerbo GX MK2
- GX Touch 50 flush
- SmartShunt 500A/50mV
- Energy Meter ET340
- Katko switch (1-0-2)
- 10x Fuse disconnector NH00 125AGg (3 spare for expantion with battery pack)
- 64x LFP cell 313Ah (4 battery packs of 64 kWh)
- BMS: JK-PB1A16S15P + 4.3 inch touch screen display
Control part in detail.
with touch (IP2x) protection
without touch protection
temperature after 4 hours charging at 200A
Why knive fuses instead of megafuse?
- Victron advises to use “megafuse of 200A” with the “Multiplus-II 48/5000/70-50”.
- The limitation of a megafuse is the breaking capacity of 2kA.
- The used cells have an internal resistance of 0,2mΩ which leads to a max current of 16kA.
- The nh00 125AGg fuse has breaking capacity of 50kA which suits the requirements better.
Advandces of the knife fuse:
- Inexpensive.
- No need to tighten to torque the connection after exchange of fuse.
- Easy to get.
Determine of fuse value.
The 125A has de best fit to 200A megafuse.
Battery pack in detail.
without touch protection
temperature after 4 hours charging at 200A
Control panel for 4 battery packs
Control and emergency stop
Adjustments of the house distribution board
Made adjustments:
- Separation of critical and non-critical loads
- non-critical (EV charger, PV-systems, airco (heating and cooling), hot water)
- critical (all other loads) after AC-0ut
- adding energy meter
- adding bypass swith of ESS