Lithium banks, service batteries, and Oceanvolt.

[Lasivian]

So, long story short I want to go with an Oceanvolt system. And I am going to have a power-hungry boat. So it seems logical to have the drive and other systems run from the same large lithium bank. However Oceanvolt suggests the "service battery" be AGM

Now I understand the value of having one non-lithium battery as an overcharge sink. But i'm curious if that's what they're talking about, or if they want the service battery system totally seperate of the drive battery system.

I messaged them but they did not go into detail about this.

Anyone have a similar setup?

Thanks.