Solar Charging dual 12 volt and 48 volt lithium batteries

[atomvoyager]

Here is a diagram of the way I set up the solar charging system on a Cape Dory 36 with a 48 volt battery for electric propulsion and 12 volt house bank. The columns numbered 1-8 refer to the corresponding labeled terminals on the transfer switches. For more info refer to this video:

https://www.youtube.com/watch?v=F5ZbSMy96K4

[Redwood1957]

This switch has got me thinking. That could be dangerous.
I looked at link looks like it's rated for 32 amps. Does anyone know the voltage rating. I'm hoping 120vac. I think I could use this as a manual transfer switch between shore and onboard inverter.
Also where would one purchase the black plastic you use for your panel faces. It is great looking.
Thanks mike

[atomvoyager]

Thanks for raising this switch issue. When you say you want to use the switch between shore power and inverter are you looking for a switch to transfer your AC receptacles between shore power and inverter?
On a small boat I sometimes put a male extension cord plug on the input side of the receptacle feed line and plug it into the inverter output when needed. Then when on shore power I unplug it and plug into a female connector on the line from the panel AC breaker.

These switches are rated for 32A at 220v/380v. In our case each switch only handles one 200w solar panel. I believe your concern is not about the load itself but that an AC rated switch used for this amount of DC load can have arcing and pitting and increased resistance over time if the switch has not been built to handle faster connection requirements of DC. Since they don't give a DC rating I assumed that there won't be much difference in how it will perform because solar is a low arcing resistive load rather than the higher arcing inductive loads of say an electric motor. They also sell on the same listing page an 8 terminal switch rated 63A. Do you think we should swap ours for those higher rated ones?

The switch panel faces are black 1/4" HDPE plastic board from the link below. They are somewhat flexible though so they might sag on larger panels that aren't supported well. If you need something more rigid then you might use plywood faced with black matte formica.

https://www.amazon.com/gp/product/B08M6FKPHB/

[pmnfernando]

Admittedly, electrics is my achilles heel, so far.

From research ive come te see that there are 2 big areas. The switched and unswitched one.
The unswitched one deals with all power coming into the vessel, ie, anything that charges the batteries.

Solar panels fall onto this area.
Usually batteries and charge controler come with smart management systems that shut off once they see the battery/devide is fed.

I think you might be putting an extra step onto the system. might be more straightforward to wire the panels onto a busbar which then sends the juice to either voltage system.