We don't have solar, and only sometimes do we use one or the other of our two generators for sunless battery charging.
I have found that what works well for quiet and fairly fast charging of our 230 AH AGM coach battery bank is to merely idle the main Ford engine a bit and let it's alternator do the charging. There's no vibration in the coach during V10 engine idling and it can barely be heard just outside the coach.
This works very well, and from what I'm reading in the forums, seems similar in principle to certain modern Class B/C RVs using autostart idling of the main engine for non-solar fast charging of the coach batteries -> except in my approach with our 2005 Class C I have to manually start the engine to do it.
If necessary, we can maintain a slight air pressure inside the coach interior so as to keep any tail pipe fumes from entering.