Hi!
I’d suggest looking into the documentation for modern inverter systems, because things have changed a lot in the last 15 years. I’m an electronics engineer, and even I have had to admit that the market and the technology have moved on quite a bit. These days, inverter systems can do much more than just convert DC into AC. Depending on how the system is built, they can work together with solar charging, use the available solar energy first, draw from the battery when needed, and even lean on the grid if the demand goes beyond what your solar and battery setup can provide. They can also top the battery up gently from the grid after several cloudy days if that is how you choose to configure it.
I use Victron myself, and one of the things I like is that they have built a whole ecosystem around the hardware. You can monitor the installation from your phone, have the information on a dedicated screen, and tune the system so it behaves in a way that makes sense for your real daily consumption instead of some theoretical perfect scenario. A lot of the early progress in this area came from boats and campers, because those systems spend most of their time fully or partly off grid, so they had to become smarter earlier than domestic systems. But now the same ideas are becoming much more common in houses too, especially where people want a bit more resilience or flexibility.
If you already have a breaker panel with circuits separated in a sensible way, it is not especially complicated in principle to move some predictable loads onto the inverter backed system while leaving the rest on the grid. Lighting is often a simple place to start, and other steady and easy to predict loads can also make sense. The more demanding loads need a bit more thought, especially anything with motors, pumps or high starting surges, because sometimes the challenge is not the normal running power but the moment they first kick in. That is where people can get caught out if they only look at the label and not at how the equipment really behaves.
I would still say it is important to be careful and to follow the local rules and standards wherever you are, because once you start mixing batteries, solar, inverters and existing household wiring, you want to be sure everything is properly protected and done in a safe way. Cable sizing, fuses, breakers, connections and isolation all matter, not just for performance but to avoid damage or fire. That is one reason I often prefer smaller or more self contained systems rather than trying to rework an entire house in one go. Starting with a more isolated setup lets you learn a lot without having to interfere too much with the main installation. And yes, there is still a very good reason why so many people move toward 48 volt systems. For the same amount of power, the current is lower, so the cables between batteries and inverter do not need to be so heavy, losses are reduced, and everything generally behaves better. Cable runs matter too, of course. The longer the distance, the more loss and heating you get, so keeping the panels, batteries and inverter laid out sensibly makes a real difference.
I’d also be careful about building lithium batteries yourself, especially if we are talking about LiPo. Personally, I do not think that is a very prudent place to start unless someone already has real experience and understands exactly what they are doing. With that kind of battery, a proper BMS is not optional, it is essential, because it has to manage charging, discharging, balancing and temperature, and those things are exactly what stop a battery pack from becoming dangerous. When lithium batteries go wrong, the fire is not just a small technical problem, it is serious, very hard to control, and nasty both in terms of toxic fumes and sheer fire intensity. That is why I would rather use something that comes with real guarantees and a proper safety design, even if you begin with a fairly small amount of storage. If you find that you are actually using it and it makes sense in daily life, you can always add more later and duplicate the capacity in a safer and more controlled way.
I do not know if that helps move the idea forward, but I think you are looking at it in the right way. It takes a bit of patience, but honestly that is part of the fun !