House DC bus stays energised by Victron chargers when main battery isolator is switched OFF

DIY
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1

I’m pretty much at the end of my marine lithium build but am confused with one aspect and would really appreciate some advice.

My set up is:

Victron Lithium 300ah > Main isolator switch > T-Class fuse > Lynx BMS > Lynx Distributor > feed to secondary busbar which has all my house loads on it.

On my Lynx Distributor, I have:

  • Orion XS DC-DC output;
  • Phoenix IP43 shore charger output; and
  • Feed to secondary house busbar.

When my main isolator is OFF, I would expect my house system to be dead (which I assume is best practice and how it’s intended to behave i.e. isolator OFF = house bus goes completely dead). Is this right in terms of best practice/standards?

However, as it stands now, even with the main isolator OFF, the Lynx Distributor is being energised/backfed by charging sources (the Phoenix when shore power is connected, or the Orion DC-DC charger when the engines are running). So I don’t have true isolation which I feel is incorrect.

I understand this is happening because my charger outputs and house loads are sharing the same busbar inside the Lynx Distributor. When I turn off the battery isolator, the chargers still stay active and keep powering the entire busbar and therefore my house loads.

To fix this, I think I need to install a second manual isolator between the Lynx Distributor output and the secondary house busbar.

So when I have the second isolator OFF, the house loads are completely dead/isolated, but the chargers can still safely charge the battery in the background.

Am I on the right track? Is this how you’d setup to achieve true isolation or would you do it another way? Or have I got my setup completely wrong?

Thanks in advance

2

Usually if there is space being able to fully isolate all components input and output should be there if you want to be thorough.

In short and more technically correct label this is the main battery isolator. (Isolating the specific component)

Then this is just a load isolator cutting off power to the consumers.

Depends on what you are aiming for and how it is already being used, it is possible to use remotes to switch off the orion and phoenix (which would be off if it was not plugged into power)
True isolation is different. And the orion would have to have disconnects on both sides.

3

Since you have a Lynx BMS, all your charge sources should be controlled by that. Either through communication over the Cerbo, or if a charger is not compatible with that, then through the physical ATC contact.

So by switching the lynx BMS off, all your chargers should either power down through communication or ATC. If not then somethings wired or setup wrong.

While you can still use the main battery switch, also switching the lynx BMS off should solve your issue.

4

True, the safest system to work on is the one that is switched off.

To be able to remove components or sections do require isolation of wiring to allow the system to be re energised without live ends flapping in the wind.

So i depends on (regulations) and what the aim is of the isolation.