Any Electrikery whisperers? who can work out what the heckedy heck is going on here - I keep blowing fuses.. but don't think that's the end of my woes

[G00seman]

Any help would be greatly appreciated..
So these are the back of the blade fuses that are in the van and a relay. It all seems a bit 'Amateur/Heath Robinson' and a bit of a buggers muddle.
I'm assuming once the relay is activated the power comes from the starter battery and the leisure battery is not charged as part of this setup.
The sockets are 3x 12v/USB sockets and the lights are 4x interior LED. The 'battery' is a leisure battery - 75AH (650A).
The 10A fuse for the 'top' socket blows, seemingly randomly (i.e. without load) but when it does this the lights stop working (until I replace the fuse). I've checked the wiring at the sockets for dodgy conx - all seems ok.
Can anyone spot a reason for this?

otherwise I guess I have 3 options.
1, Sell the van
2, Buy a bulk load of fuses.
3, Do it properly and label everything, (and add a full suite - hookup and solar and inverter)

I think I've answered my own question

 

[Loz]

I think I get it.
As the leisure battery is one of the circuits the 10A fuse blows when the leisure battery gets low and the inrush of current when connected to the starter battery, can be many amps up to whatever the cable will carry.
So yes, needs a bigger cable/fuse and a bigger more appropriate relay, the factory relay is rated at 100A so a DC-DC charger and bigger supply cable fused appropriately would be better.

 

[G00seman]

I think I get it.
As the leisure battery is one of the circuits the 10A fuse blows when the leisure battery gets low and the inrush of current when connected to the starter battery, can be many amps up to whatever the cable will carry.
So yes, needs a bigger cable/fuse and a bigger more appropriate relay, the factory relay is rated at 100A so a DC-DC charger and bigger supply cable fused appropriately would be better.

Thanks for the reply