I have not seen switches used in any Victron example between the controller and the battery. I have seen a PV isolator used between the panels and the Victron controller in the Victron examples but not a switch, although I see no reason one cannot be put there instead of an isolator.
Note: the Victron schematic diagram link above is for a large boat installation (BTW: I don't understand the need for the 40 A resettable breaker between the MPPT solar controller and the battery bank. The bank is fused for protection as is the controller itself).
BTW: In your 12v (or 24 V) system be sure to use DC rated fuses not AC fuses. For example, your battery should be fused at or near the positive battery terminal
Below is a link to a system using Victron components that employs a switch between the panels and the MPPT controller. This is not necessary but may be useful as an always on switch unless you need switch it off to add or trouble shoot the panels or the battery bank, as has been discussed above.
If you decide to add a switch read this (it seems a switch between the battery and the controller may not damage the controller - but you decide after reading):
https://community.vi...n-port-b-1.html
https://amsolar.com/...ategory/Trailer
Edited by ckent323, 06 May 2020 - 05:57 PM.