No kidding. I've been wanting to do something similar. I would have to sub it out because I don't have a big old giant brain like you do. Cost benefit analysis wise, how long until it pays for itself?
The ROI on the gridtie system will happen between 9 and 10 years if electricity stays the same price.
Most solar panels have a 20 year warranty so it should be good for a while after it pays for itself.
I went with all commercial grade NEW components on that system so paid a premium price for them.
Hard to say on the battery backup system.
The single most expensive part was the batteries themselves.
They are CALB LiFePO4 prismatic cells with 20-30 year life, 3000+ cycle life, wide usable voltage range and are much safer than Li-Ion and standard lead/acid batteries.
The down side of these cells is they are 3.2VDC nominal so you have to string them together in series of 4 for 12V or 8 for 24V.
When the batteries are in series, the charge comes in at each end and starts filling cells.
They may or may not charge at same rate due to internal resistance of each cell so you have to manage the batteries.
The ElectroDacus SBMS120 (Solar Battery Management System 120A) charge controller was designed from the ground up as a battery management system specifically for these batteries.
The designer lives in Canada and is entirely self sufficient and even heats his house with solar so he's pretty good at wringing watts out of solar panels in less than perfect conditions - I've seen my 2450 watt system make 2580 watts under ideal conditions and even managed to take a picture of the screen.
The BMS part monitors individual 3.2V cells in the string as they charge and can add additional amps to batteries that are slower to charge due to higher resistance and cut back on quicker less resistant cells to keep them in balance.
It can also control your inverters and generator auto start if you want it to.
The second most expensive part was the Hybrid Inverter due to the requirements I had and it produces really clean 120/240V Pure Sine wave output so clocks, computers, and other sensitive stuff runs perfectly.
It does lots of magic stuff and I am very careful with it and want to keep that magic smoke INSIDE.
It does excellent job as simple inverter and has charger built in but it's not optimized for these batteries so I have the charger turned off.
It can act like a UPS with grid feed thru that picks up off of batteries if grid goes down.
It also does lots of other tricks but the main one is AC Coupling.
If the grid goes down, AC Coupling allows me to use the battery back up system to "trick" the grid tie system into thinking the grid is back up and allows it to turn on so I can use that electricity.
That's a very simplified explanation of AC coupling as there are considerable safety interlocks involved to make sure I don't accidentally send power to the grid while linemen are working on it.
For this project, I bought used 24V 245watt solar panels to complement the 24V battery bank.
The panels are 2 year old premium panels that cost $810 for a pallet of 10 delivered or .33 a watt.
Buying used panels over new saved about $1600 and I will probably buy used panels from now on.
At this point in time using data I have so far, it looks like it will take 11-12 years to pay for itself.
On the flip side, if we have a power outtage that lasts more than a couple of days, saving my freezer full of hand raised grass fed beef and refrigerator full of food would be priceless.
Unfortunately, our grid will be taxed more and more as folks shift from fossil fuels to electric.
And it's only a good hacker/bad security guy away from being held hostage.