Will try not to bore you all with this but I researched fuses for 4 x pylontech US5000 batteries (Lithium in general) and it seems like Class-T fuses (or equiv.) are the preffered choice due to high short circuit current and the possibility of Mega fuses not being suitable.
So I purchased Lynx Class-T and then come to realise that the minimum fuse size is 225a which is too big for Pylontech's cables (rated @ 100a?). Recommended discharge/charge rate is 80a with a max of 100a (can be more for short periods)
Anyway I am stuck deciding now which will be the optimum setup/wiring.
Option 1.
Use the Lynx Class-T fuse with a 225a fuse for each battery (limiting current on multiplus) Fuse wont protect the cable from over-current apart from in a short circuit situation maybe?
Option 2.
Double up the dc cables so there's 2x25mm from each battery to the 225a class-t fuse which then should bring the fuse in line with the current carrying capacity. I just need to see if I can fit 2 lugs in the lynx on each terminal. I would also need to cut off the existing 8-25 lug and replace with a 10-25 for each cable (16 in total)
Option 3.
Create 2 banks of 2 US5000C using the intemediary dc cables and thereby creating a current more inline with the fuse rating but still only 1 set of dc cables to the class-t lynx. I still have reservations about the cable current being only 1x25mm still as this will limit what i can charge/discharge.
Option 4.
As option 3. but double up the cables so the current carrying capactity is better suited for the expected charge/discharge current and the 225a fuse. Still need to cut and reterminate the pylontech cables but only half as much as option 2.
Option 5.
Forget the class-t and go back to the distributor/power with 125a mega fuses. Dont feel comfortable with this though due to the high current under fault conditions.
Option 6.
Go with a NH00 fuse carrier with a 100-160a fuse per battery (I need to check curves etc..) then from the carrier to a combined bus bar (600a/70v) or to the lynx distributor/power in (no fuses) to save money buying new busbars as victrons are £200 each.
I had issues uploading images and embedding so if you can't see images, the link to all options is here: https://drive.google.com/file/d/13xG9NOGmaDa0Cfbbcxv-v8ii_SCjgQ8M/view?usp=sharing
If it makes any difference, its then going to e multiplus 2 48/5000 with a couple of MPPT's added in. And I might be adding a couple of US3000 down the line.
Thanks in advance for all your help and suggestions.