Solar connection question

The solar module doesn't care if you disconnect it or not. The charge controller shouldnt be damaged by that either so theyre probably are just saying that so you don't draw a spark when you disconnect. If you're really worried about it just turn the solar module so there's no sun on it and then disconnect. No sun no current will be flowing in that line.

My breaker recommendation was only if you were disconnecting the bolted wire(s) going to the converter and you were charging from 120Vac at the same time. If not then you don't need to turn off the converter or any other breakers.

Either set of battery posts are fine, they are connected.

You can disconnect the solar charger when you need to.

I would shut off the on board converter and any 12V loads before disconnecting if you use those posts, so that there is no current flowing in the wires your working on other than what's coming from the solar charger.

The converter can be shut off using it's circuit breaker. If you forget it's not really a big deal, you'll just get a spark which won't hurt you, more annoying than anything else.

If you use the bolted terminals just be careful never to short the battery + terminal to either the - terminal or to the trailer frame, that will short out the battery. The typical way that might happen is through the wrench when you turn it. That's why it's better to disconnect the negative first when working on a battery. When you disconnect the negative you are isolating the battery from the frame, but you still need to be sure your wrench doesn't directly short between the battery posts. I tape up the wrench I use on battery terminals so it won't accidentally short.

Do make sure you have a fuse on the battery positive for your solar connection. Not sure if your kit comes with one or not. If not then add one. A 15 amp inline fuse will work.