Lynx Distributor blown 60A fuse from Orion Tr smart Isolated 12 | 12 30

[CauseLessHarm (D McRae)]

Hello, I’m looking to troubleshoot why the 60A fuse in my Lynx Distributor is blowing every time I try to connect the Isolated dc dc battery charger.

A bit about my setup.
I have created a separate system in my classic hymer to charge devices, run starlink and power my espresso machine (very important).

I currently have a 280ah LifePo4 battery connected to a Lynx distributor, with a Phoenix 12 | 1200, charged by a 400w solar system run through a MPPT 100 | 30. These all work flawlessly, and powered us through a 10 week trip through France earlier in the year.

The trouble is charging the LifePo4 battery from the starter battery. My “victron setup” is all in the back of the van. I’ve run two <8m 35mm2 cables from the starter battery to the back. The positive is stepped down to < .25m 10 mm2 cable through a 60A mega fuse (not blown). The negative is stepped down to a < .25m 10 mm2 cable through a bus bar. The Orion is then connected to the Lynx distributor with <1.5m of 10 mm2 cable, where the 60A mega fuse constantly blows when connecting the charger.

Further, the 280ah LifePo4 is connected to the Lynx Distributor via monster <2m 95mm2 cables.

I ran through 2 fuses before running out, more on order, but wondering where I should start in troubleshooting where I’ve gone wrong.

I have shunts and monitors that I haven’t even attempted to install, as I’m wanting to get the charging system working first. I am an admitted novice in all of this, but have done a considerable amount of research to determine what products I needed, cable requirements etc. I feel like the false confidence in having a little knowledge is probably dangerous here.

Any pointers on where to start troubleshooting are greatly appreciated.

[CauseLessHarm (D McRae)]

Ok, new fuses arrived.

One thought I had. Is it recommended to geound the leisure battery to the chassis?

It’s currently not, and working fine with solar, but I wondered if that could be an issue.

[pwfarnell]

I would start by checking if you have a short on your cables somewhere. On the orion terminals have you got some loose strands between terminals, have you got the input and output cables correct and the polarity correct, note the cables go in order + - - +.
If the wiring is correct then the only reason for blowing the fuse is a faulty unit, contact your dealer for support.
The two systems do not need to share a common ground as the unit is isolated per your title. My experience with boats is house and starter batteries share a common negative.

[CauseLessHarm (D McRae)]

Thanks so much for your suggestions. Whilst I can’t confirm that there were any stray strands, I did pull each of the cables out and “re-seat” them, and I now have a functioning dc - dc charger. Very much appreciate your help. Now on to the battery monitor.