Dull Men's Club

I don't know where you life and what your rules are. But here in EU(NL) is now also possible for renters to put a solar panel on their balcony.

Or avoid all the rules, and use an camping off-grid power system

Nice!

Back atcha. 19.2 KW would be amazing and probably way more than I need, but I don't have near enough south-facing roof (sadly, I have plenty of north-facing roof. With these 200W panels I have, my back of the napkin measurements seem to make my limit about 6 KW on the roof. I may check the measurements of the 320W ones and see what that gives me, but I'm thinking it'll be close enough that it's not worth the extra cost.

I do have plenty of back yard, though, so after I get this up and running, I may do another string or two as a ground mount setup.

Grid-tie was my original plan, but power company has too many hoops, restrictions, and red-tape to make it worthwhile. Plus, I still need a backup power solution (e.g. a Generac) so I went ahead and got some big batteries right at the start since I was already planning on spending about that same amount for the generator + installation.

It's been pretty great even with this little setup I have now.

I've been wanting to do this for years, so I finally justified the cost of the big system I just bought by combining it with my need for a backup generator. I could stretch 30 KWh of battery to about 2-3 days even with no sunshine to top them up. I may still get a small generator as a backup backup just to charge the batteries, but I won't have to spring for a Generac and having that plumbed into the gas and wired in. Plus those don't seem super reliable as both neighbors who have those always seem to have service techs coming and going.

Maybe fridge/freezer?

That I'm not sure, but likely various misc/intermittent loads that aren't running from the power station (bathroom lights/fan, electric range, etc). The one right before 8am is probably the coffee machine, and the bump around 1pm is when I made lunch.

The graph is also confusing. Like, I know my homelab runs at about 0.25 KWh continuously but the graph is in half hour increments so shows it as half that.

The main things I run from it are all downstairs in the basement and within reach of extension cords: homelab, WFH office, washing machine, etc. Those are lazily run through the drop ceiling to not be trip hazards. I did install a second outlet behind the fridge upstairs and ran romex down to the basement for it. That was from an earlier plan to have a subset of outlets that were on a backup circuit, but I changed my mind and opted for a whole house solution. So I just put a plug on the end of that (basically turning it into a sort of heavy duty extension cord) and hook it into the power station during the day.

To transfer them back and forth, I just switch where they're plugged in. They're all on UPSs (including the fridge - long story) so there's no power interruption. For other stuff (like charging the lawnmower and power tool batteries, etc) I'll just either run an extension cord out of the basement or plug the tool chargers into it (it's got 4 outlets and can put out 2,000 W).

The graph depicts the utility usage, and the bit in the middle where it's low/negligible throughout the day is just those "base" loads missing / not using power.

The small setup I have now is based on this so I currently have to manually move where things are plugged in, but the 10 KW inverter I just bought is a hybrid one.

It'll charge, invert, and load balance automatically and there's configuration you can program to set the cutover levels, charge/discharge limits, whether it should prioritize power the loads or charging the battery, and such. It can also mix utility and inverter power and switch between the two pretty seamlessly (10ms switchover which is comparable to a UPS).*

*According to the data sheets, anyway. I ordered it today and wont' have it until probably close to end of the month.

I think its common to think about these min-max scenarios about squeezing every bit of efficiency out of a solar system deployment. I encourage others to go down this through process, but don't get too discouraged at the end when you start looking about why this gets really complicated really quickly.

In your example of trying to bypass the PC power supply and feed DC power directly to the PC, I can think of a number of challenges to that working (or being reliable).

• Even if you're avoiding the switch from DC to AC and then back to DC inside the computer, that does nothing to step down the voltage produced by the panels. In a PC you need the following voltages 3.3V, 5V, 5Vsb, -12V, and +12V. On a PV solar system, you'd get anywhere from 18v on a single small panel, to 60v on a large panel, to 400v on a whole residential array.

• Just because the panels are producing DC doesn't mean its necessarily clean. DC just means the current flow never switches direction. Lets say you set up a whole bunch of buck converters to produce all the right voltages to feed an ATX power supply. What happens when you get a cloud shadow moving across the array and the power produced drops for a few seconds? PCs are expecting very clean, very predictable power. That voltage sag would likely be enough to interrupt the operation of the PC.

Would it be possible to engineer a high quality power supply with enough capacitance and batteries to provide clean power from solar? Sure, but that's a pretty complicated engineering exercise. You've already go two very well designed power systems: the inverter(s) from your array and your PC power supply. The only cost is 3% DC to AC conversion loss.

Unless you constantly want to be messing with your solar deployment, you quickly realize that reliability is usually the state to optimize for. Get your system working at a decent expected state that will stay working without intervention for a long long time. Optimize elsewhere.

I have three potential service goals: essential power, whole house, and finally whole house and shop. I’d rather start on the small side, but want to be able to reuse gear, if at all possible, as I go up in capacity.

There's a downside to that approach. Thats essentially two different scenarios (partial and full). Unless you get into complicated load shedding, you'll potentially have to get some pretty monstrous batteries which can get expensive quickly. You might even have to size up inverters to offer the instantaneous power demand that you might get with running the house and some large power tools simultaneously. If you don't you'll trip breakers and then have no power anywhere until you manually shed some loads.

How many kWh a month do you use?

Depends on the month as everything except my furnace and hot water heater are electric. In March, when the furnace barely ran and didn't need any ceiling fans, etc, I used 391 KWh and my bill was $105 for the privilege. In July when I have to run the A/C almost constantly, I use close to 1,300 KWh and don't even want to say what that costs me. I work from home, so I kind of need to keep it comfortable all day as well as run my WFH office gear. (Otherwise, I'd bump the thermostat up until I get home in the evenings)

I've also got a homelab, but I've downsized it enough over the years that it's down to ~250W continuous (yay USFF PCs! I used to use old rack servers that were 200W each).

Any youtube channels you'd recommend? Other resources? Advice?

I'm more of a hands-on learner, so mostly I've just played with it in different forms for 6 or 7 years and started small or Googled specific questions i had. The main thing I learned is that on a good sunny day, PV is like a waterfall and you often only need a glass of water from it. Unless you're going grid-tie to absorb the excess, storage (batteries) is important otherwise it's just wasted. The rest I guess I'll figure out as I get this one up and running. As far as the electrical work, I grew up helping my grandfather on jobs (he was an electrician) so other than referring to NEC for some specifics, I'm pretty comfortable/confident with that kind of work (doesn't make it any less of a pain in the ass though haha).