question

Typically, the DC-to-DC Orion is connected between two battery banks.

Connect the output from each ...

1) Centaur

2) Orion

3) Solar MPPT

Directly to the LiFePO4 battery bank

Connect the Orion Input to the Port Battery

Now, why do you need the Battery Isolator?

The isolator exists because of the manufacturer and their electrical design. The house batteries (bank 3) need to be isolated from the engine batteries so that the house loads don't drain the cranks. Starting the engines is the priority.

The problem that I have with attaching the Centaur to the LiFePo is it does not have a setting for the Lithium, only Lead Acid, Gel and AGM. Battery selection also cannot be set per bank, so if I change it to Other then it messes up the charging of the other banks.

If I connect the Orion to the port battery I risk running the port battery down if I am not connected to shore power, am not running the engine and the solar is not generating enough output. I can't risk running it down.

What I could do is install a small Lead before the Orion, attach the solar to the lead and then have all house loads come of the LiFePo. That would simulate the starting battery and could be run down without impacting my ability to start. The reason to have the solar on the Lead battery side is so that both the Lead and the LifePo are charged when the solar is active.

Something like this:

Thoughts?

The Orion should work as you wish. But guesswork on my part.

Suggest you download the manual and read up on the configuration options. Also if you don't have it already, install Victron Connect on your phone, go to the demo library and find an Orion charger. Then play around with the settings to ensure that the options fit your system.

I've a feeling that the centaur output terminals are connected internally. If that's the case make sure the Orion input/engine detection is high enough to only switch on if the centaur is charging or in float mode, otherwise you risk charging the lithium from the lead batteries if there is an internal connection between the Centaur outputs.