Advice on electric system

[pablodnb]

Hello, Thank you for all the information on this forum.
I am a T4 owner in France, so no T6 but this place is really full of advice and knowledge, that's why I am posting here today.
I made a schematics for my van with a very simple setup and I would like to have to feedback, specially on fuse and wire size.
Thank you very much!
Here is the schematics.
Best,
Pablo

 

[roadtripper]

From a quick glance:

You need a master fuse in the battery +12v (not just an isolator) as close to the battery terminal as possible.

60A fuse on the supply to the DC-DC seems very low for a 50A rated charger.

I wouldn't recommend breakers over fuses but if you do want to use them ensure they are the high quality marine type ones not unbranded generic items from Amazon/eBay.

 

[t0mb0]

Whilst we're on fuses - that 150A fuse between the bus bar and the fuse block is likely way too high, the fuse block itself won't be rated that high and the cable almost certainly won't be. Your fuse always needs to be the first thing to blow, not the cable/box/equipment/etc.

 

[pablodnb]

Thank you for your input!
-The manual from Renogy DC DC charger says this:

So it needs to be at least 75A and not 60A ?
- you said I need a fuse before the isolator, but I put a fuse before the fuse-box. If I understand right I need both ?
- Also for the fuse before the fuse box, the Blue Sea Fuse box is rated 100A, so I need to put a 100A fuse, is that right ?

Thank you !
Best.
Pablo

 

[t0mb0]

Thank you for your input!
-The manual from Renogy DC DC charger says this:
View attachment 249259
So it needs to be at least 75A and not 60A ?
- you said I need a fuse before the isolator, but I put a fuse before the fuse-box. If I understand right I need both ?
- Also for the fuse before the fuse box, the Blue Sea Fuse box is rated 100A, so I need to put a 100A fuse, is that right ?

Thank you !
Best.
Pablo

I think 100A between the fuse box and busbar is still much too high, you're never going to want to pull 100A there and you'd have to run 16mm cable at least (which is massive) for the cable to cope with that current. I think the equivalent fuse in my system is about 20 or 30A from memory.

 

[roadtripper]

Remember that the fuse is there to protect the cable not the device at the end of the cable - so size it to the cable and place it as close to the voltage source as possible.

So, in general,
1. Work out peak load on the circuit
2. Size cable for peak load (keeping in mind most documented rating is for the cable at 70 Centigrade which may be too high in a van)
3. Size fuse to protect the cable