Solar switching options for separate 12v and 48v lithium banks

[Atomvoyager]

I came across an article in Good Old Boat magazine on setting up 12v solar to charge both 48v lithium electric motor bank and 12v lithium house bank. He used a simple system with the panels connected in parallel and linked to a two-way switch. One mode charges the house bank with a 12-volt Victron 100/30 charge controller and the other charges the engine bank with a 48-volt Renogy Rover Boost controller.

I'd been told by my ePropulsion supplier that I need to isolate the grounds on the 12v and 48v chargers to avoid problems. Apparently I need a switch with one input circuit of two conductors and two conductors each for two output circuits. Can someone provide a name or link to a switch for this? The single switch avoids the problem of two separate switches that could allow the solar to try to go to both banks at the same time if they were both accidentally left in the on position. Also, are the Renogy Rover Boost and Victron 100/30 good choices here?

Because I'm installing an ePropulsion E170 48v lithium battery that requires it to be powered on to accept a charge and we don't want it on all the time with it's power drain, and for some redundancy in case anything fails on the 48v system, we can't just run the solar only to it and then rely on a convertor to charge the 12v house bank. But we will have a 48v to 12v converter to charge the 12v bank when the motor is in regen mode.
Thanks.

 

[Atomvoyager]

Here's an 8 terminal multi-pole transfer switch that looks like it could work.

https://www.amazon.com/dp/B088PC4QVC?

These transfer switches are often used to select generator or shore power to supply the boats 120v circuits. I'm still not sure if this is the way to go since I haven't seen this discussed on other threads yet.