Using 3 MP2’s, and only 1 battery, what cable size should I use from battery to the distributor?
Manual says 35mm² for the MP2 3000 48v. But what about before the distribution point?
Cable size should be the same or greater, depending on total length and any other loads on the busbar.
It is always good to have fallback information to check conductor sizes for your system.
I found this one:
https://www.victronenergy.com/upload/documents/The_Wiring_Unlimited_book/43562-Wiring_Unlimited-pdf-en.pdf
It’s not in the wiring guide.
Yes, but by how much? No other loads, just 1 battery and 3 MP2’s.
OK, so your Battery cable max current is the total of the three MP2’s. Generally this would mean that the cable is 3 times the size.
For instance, 3kW@ 48V is 62.5A, x3 is 187.5A, so your battery cable needs a ~200A rating.
This is 70mm^2, which has 194A in free space. There are cable ampacity charts on line.