New victron install - a couple of questions

[psychiatrist]

Hi everyone, I am soon going to be installing my home ESS setup, comprising of:
-Cerbo GX-S
-Multiplus 48/8000
-RS450/100
-MPPT 250/70
-25 x 440w panels (10 pointing west, 15 pointing east).
-Lynx
-3 x Pylontech pelio

My first question, more advice, is what is the maximum recommended dc battery cable length? I am hoping to site the batteries about a 12m cable run from the rest of the kit, and feed the dc battery cables through some purpose installed drain pipe so that it is hidden.

I also have a victron ev charger already installed, standalone, which will be brought in to the new ess setup.

I have previous experience with victron after a small motorhome install I did. I look after a 3-phase system for a sports facility and helped out where I could with the install.

[lxonline (LX)]

@psychiatrist

maximum recommended dc battery cable length

As short as possible.

If you have to make long lengths you loose efficiency and have the most awful voltage drop which will result in undercharged and over discharged batteries. (Amongst other things like dc ripple = bad).

One ‘work around’ is oversizing the DC cable, but at 24m ( return length since that is how battery bank length is used) even 120mm² cable will have 3% volt drop. You would need to double up to reduce that to an acceptable level.

Volt drop

A good read on some basics is wiring unlimited.