Hello there folks!
Apologies in advance if this type of question has been asked to death here, I have searched the previous posts, but I couldn't find an exact answer.
I'm building a DC-coupled ESS system with a Multiplus-ii 48/5000 and am slightly confused by the battery requirement part.
Some notes, I am aware SOK isn't officially supported and that the guidelines say 200Ah as a minimum, so this is all at my own risk.
Based on what I've read, the minimum battery requirement is due to the inverter's current draw, and I should be able to limit the current draw via GX.
Question 1 - is the above right?
If yes, then the next part that confuses me is the actual current draw of the inverter. Normally, to get the current draw I'd use voltage/watts, traditionally that would be 48/5000 = 104.167A. However, as I'm technically going out of spec here, I'd like to be extra careful, even pedantically so and I get a bit confused about what voltage to use.
Battery specs:
- 16S configuration so the voltage is 51.2V
- 1C discharge rate is 100A
- The peak discharge is 200A for 3 seconds
Question 2 - For the current calculation, should I use 48 volts or 51.2 volts?
Question 3 - Does anyone know how long the Peak Power output lasts? I can only find references to a "short time" and for my less-than-optimal setup, would I need to put any consideration into it?
Just a note, while I am using the multiplus-ii 5kva, my actual power consumption would be around 3kw peak. However, in the future, I will be using more power, so the headroom is needed, but when that happens I'm defo getting a second (or third, fourth, etc) battery. In the further future, the plan is to expand this to a 3-phase system with 3x 5kva inverters. Essentially, I'm building the start of a much larger system, but it will be expanded over time - honestly, I love that this is an option!
