FWIW, all of my electrical and electronic loads, except engines, come off of the house bank. Dedicated engine start batteries and the ability to parallel to start the engines in a pinch. This sounds like what you have now - and is most common.
2 issues I've had with this setup:
- when the house bank ran down I could not start the generator
- when I put heavy loads on the winch
I sometimes get "Low Battery Alarm" from the GPS
So yes - any / all equipment
fed off the main bank will see the voltage transient spikes / under-voltages. How risky that is - well, that's an entirely different question. Even some 'modern' systems are affected by what I'll call 'dirty' input voltage. Everything from Splendide Washer/Dryers (need pure sine wave) to LED lighting
(if not current-limited).
I would prefer to have a dedicated bank for the windlass
/ furlers. That way if one 'function' drains its power source, you still have options. I would want the ability to cross-connect all sources of course. You never know when you'll need to start the genset using the windlass bank, ya know?
Since you've already started your upgrade project
, now might be the time to design a 3-tier system. I'd consider it to be worth the effort.
Good luck with the project
whichever course you steer.