Hi guys,
I am wondering what you would choose between these 2 options :
Option 1 : 2 multiplus 5000/48
Option 2 : 1 multiplus 8000/48
What would drive your choice ?
Context: ESS installation with 1 PV array 8kWc, Pylontech Force L1 14.21kWh that will be extended to 2 x 14,21 kWh in a few month (linked to budget ).
Thanks a lot.
Do you have a single phase or three phase system/home in general?
If you have a 3P system/home I'd go with the dual 5000s. In that way you could add a third and split them across each phase in the future. If your system/home relies on a single big phase the 8000 is the way to go in my opinion.
What do you mean with redundancy? How likely are you going to push the max power output of the 8000? If a lot then maybe a 10K model is better? Keep in mind Pylontech recommends pulling around 60A from the L1 14.2kWh model to ensure batterylife. 2x14.2 equals 120A. At 48v this equals around 6000W.... Did you think about that? (source: Low Voltage energy storage system- 20LV030904未转曲 (cloudinary.com) )
While it may look like two units in parallel would provide redundancy, there's a huge cost associated with the design of such a system. Switches would need to be installed to isolate each unit and connect to the AC in and out, the DC and the control connections. Plus you'd need to reprogram the working unit to function as a single unit (not as part of a paralleled set). There is nothing you can design that would permit automatic failover to a single unit.
As others have said, wiring a single unit is much simpler.
I'd always go with a single unit over paralleled units.
I would always prefer a single big unit over parallel smaller units that rely on data communication to work properly.
There is a 10kVA 48V Quattro too btw. if you want go bigger, I think 15kVA is the current upper end for the Quattros.
See Victron info on parallel systems, also need to make sure all wiring is symmetrical. https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems
I would choose one bigger unit.
Reason: significantly less wiring and less space needed.
Thanks a lot guys !
I understand your answers, all good points.
But what about redundancy ? How do you manage high availability ?
A parallel setup will fail when one unit fails, so no redundancy, more problems (totalReliability = relability1 * reliability2) if you have 95% reliability for a single unit (0.95), you end up with 0.90 for the whole system (90%), what means the system is more likely to fail when using parallel mode.
What do you mean with high availability? You mean power wise of productwise in case of failure?
5000W per phase is enough for us, I can power my entire home from my three units. And still have power to spare. The only time when my L2 is used entirely is when my oven and induction stove are both at high setting (2500+3500W) In that case I might use 1000W import from the grid on L2 (which is compensated via L1 or L3 so the total = 0w). This will change in the future when I remodel the kitchen and connect the stove and dishwasher on the other side of the kitchen on L3 (my less used phase at the moment). This way the loads are balanced.
In case of SHTF I won't enjoy all the luxerious options of the system and only use it for our essential needs (and maybe some of the neighbors too). In that case 5000W is more than enough :).
Thanks again for your wise answers. And Thank you Patrick : I indeed didn't think about the battery limit.
So, I'll go for one bigger Multiplus... And instead of redundancy, I will think of having a spare one in stock ;)
The same goes for the charge current.
A large 8kVa Multiplus/Quattro can charge/discharge above these limits...
