A setup that will be of interest to those with an EV with V2L capability, that are looking to be able to use their EV as a backup power source.
Some photos of an off-grid house system, 3-phase 30kVA, with AC-In wired for a backup Genset (future if needed), AC-Out 1 for general loads and AC-Out 2 configured as a smart Aux Dump load for water heating using Assistants.
Solar PV installed via Multi RS 200A MPPT Controller.
Pylontech battery bank.
Now the interesting bit. As a backup source a separate MPII GX 5kva installed primarily as a charger enabling V2X.
Power can be downloaded from the EVs onboard 230Vac 3.6kW V2L. Installed and tested at 2.2kw, but now tuned up and works well at 3kw continuous (about 60A charging power) from EVs onboard Aux socket.
The question is will a backup Genset (Petrol, Diesel or Gas) be needed in the winter months!
The AC Charger icon on the new UI is power via the EVs V2L.
Note. Essential to install a 230Vac/230Vac isolation transformer between EVs V2L and system to keep earthing arrangements segregated. EVs V2L supply not designed to have a N-E bond applied.
Most EVs V2L outputs whilst 230Vac are protected floating supplies and centre tapped 115-0-115
Works perfectly.
On a practicality front, time will tell if this capability negates the need for a backup Generator in off-grid applications.
Hey @PeakShaving could I ask you a couple of questions? I’m in Australia, and I would like to achieve V2L from my BYD Seal into my system. I’m leaving fully off-grid, and I would prefer to use my car as a backup power source, rather than having a noisy diesel generator.
Hi Carlos, sorry for delay in responding. Yes certainly. Still learning from the Pilot system we done, certainly works. The comming winter months will determine if V2L negates the need for a Genset
The solution is to install a separate Smart Shunt between the separate Multiplus acting as the charger and the common DC Busbar. It’s connected to the main system Cerbo via VE.Direct and you can chose type as AC Charger in the settings instead of battery monitor.
How is the system behaving after these months? Now that winter is in, is it still looking like the V2L could effectively replace the generator?
Regarding your observation on being essential to install a 230Vac/230Vac isolation transformer, I think I understand why you do this (not very different from what we do on yachts when we plug into marinas) but the bit that escapes my understanding is why do you need this isolator when you are extracting power from the car´s battery and you don´t need it when the installation is sending power into the car´s battery?
Yes the V2L MPII Charging setup is working very well. EV is able to discharge at around 3.4kW continuous, which after efficiency losses in the MPII outputs around 3.1kw to the common DC Busbar / Battery Bank.
It’s likely a backup generator will still be added at some point for practicality and reliability, however what I can conclude is it’s size can be kept small, if there is a big enough battery storage capacity buffer, and a single phase 230V Genset will be adequate even though the system is 3-phase 400V off-grid. Definably do not need a big 400V 3 phase generator.
On the isolation transformer application, this ensures the AC entering the MPII is 230Vac between L-N and L-E with nill voltage between neutral and earth, whereas the output from the EV V2L I have measured as high as 135V N-E floating.
The difference is the the supply arrangement. If supplying power to an EV from grid or a correctly setup off-grid system, N-E is bonded, whereas the V2L output is a floating protected supply.
