Small, “balcony solar” units hold particular appeal for renters who cannot install rooftop panels and could take portable units with them should they move.
does that even work in a split-phase system?
https://en.wikipedia.org/wiki/Split-phase_electric_power ?
Solar microinverters are usually for single phase (sync to 230 VAC 50 Hz) and the balkonkraftwerk ones are plugged in into wall sockets. Of course, if there are multiple phases in a household you can plug in an solar microinverter output into a socket that’s on a different phase. They turn off within some 20 ms or less, so this is safe if mains losing power.
There are regular solar inverters that can deal with three phases, and also some which can deal with battery charging and can operate in insular mode and are black start capable.
i’m mostly thinking of how it works when production is larger than demand in the local circuit. phase imbalances are a bigger deal when the phases are 180° out of sync.
When production is larger than local demand you’re feeding in into the power grid. If your meter can ran backwards, then you’re saving even more money.
in a normal three-phase system, yes. you just slightly imbalance one phase. but in a split-phase system, backfeeding can move the neutral point.
Just install one on each split phase!
But realistically I’m sure I read you guys have 220v hook ups of certain stuff
i’m not american, but the way their 220v outlets work is by literally bridging two phases.
Most states are limiting balcony solar to 600-1200W, which is only 5-10A at 120V. Not enough to cause problems with imbalanced loads in a home, and most peoples homes aren’t terribly well balanced anyways. It all more or less evens out by the time you have 10-20 (or however many - idk, I’m not a lineman) homes on a tranformer.
how is plug in solar safe with a male plug? strikes me as a “suicide cord” type situation (male to male extension cords people want if they accidentally string christmas lights backwards).
does the system wait for electricity to flow in before it flows out? do you only connect a small amount of panels per plug so the voltage isnt dangerous? do you just have to be very careful with the plugs? do you plug in the inverter to the wall before connecting the panels?
im not trying to imply that they are dangerous, im genuinely curious how this works.
Each unit has its own inverter that uses the line frequently to sync. Current won’t flow from the panels without the line already being active.
The panels are basically inert by design without companion home current, which is also why they are safe for lineman during outages. This makes them useless as backup power however, but that isn’t their intended use case.
thank you for the clarification!
does the system wait for electricity to flow in before it flows out?
Basically, yes!
If you unplug the micro inverter, it’ll cut the power within milliseconds of it detecting no electric signal. AC alternates around 50hz in the UK which the inverter detects and starts generating. Once it losses the hz signal it stops.
I think it’s great to invest in solar but I really question the ROI on this sort of thing. The panels aren’t optimally aligned and there’s not enough to do more than take a few cents off the bill every day.
I really question the ROI on this sort of thing
Depends if you do it right.
In the UK, you can buy 2 ~400w for about 140, then £100 for the micro inverter. I have 4 295w panels mounted on a flat, raised frame on the side of a shed and they cut my bill from £150 down to around £70 last month. So yes, they can pay for themselves pretty quickly.
And once they’re paid for, it’s all free electric! And we’re now seeing batteries with plugin style so you can store the electric to run white goods, saving even more, etc.
Also, unless you get a solar tracker, “optimally aligned” isn’t really possible. The sun moves inclination every day depending on where you live. Here in summer you’d want a more horizontal position, in winter a more vertical position which is why solar fencing is actually becoming a thing because they generate more in winter.
I’m thinking of the balcony solar, which seems to mostly be a couple small 200w kit panels vertically mounted. Even with south facing i don’t think it would run a refrigerator. It depends on the cost per kWh, no doubt.
What kind of refrigerator are you running? Around 100 Watt should be enough to run a decently sized refrigerator. Solar panels are somewhat forgiving when it comes to the proper angles, 100 Watt peak should be easily achievable with an 800 Watt setup, even if they are very badly angled. Sure, not 24/7, and maybe not all year round, but that’s not the goal.
Also, since you focused on ROI, that’s the nice thing about small installations - basically all the energy generated is directly used by you, meaning it directly replaces energy you would have had to buy otherwise. This is the more expensive kind of energy, and you “make” more money with that as if you sold the electricity. The ROI of solar power (for everyday people) goes down the bigger the system gets, as you won’t be able to use all the peak power when it is generated.
For context, I’ve got experience with midsized solar and currently have a balcony-esque 500w array mounted for the correct angle for my latitude. My panels are free but the battery and inverter were about $600. I save 10-15 cents a day in summer. That’s a ridiculously long payback and it doesn’t give me enough for a backup. If I had 2-3kw solar it would be different, spreading the inverter cost more thinly.
It depends what your consumption is I suppose. If I am able to generate 20% of my consumption that’s a help, maybe I’m wrong, I feel the 500kw balcony vertical install won’t cover 20% of a household.
I’m really wondering what your situation is then. That sounds like a worst-case scenario. Do you have a tree in front of your panels? Are you only running electrical equipment at night? 10-15 cents a day in summer either means your electricity is damn cheap, the panels don’t generate much for whatever reason, or you are not using it when it is being generated.
Also for 500 Watt peak a battery does not make much sense, if at all it should be a small battery to buffer peak demand (the refrigerator compressor turning on or other similar high-power short duration load, but that’s definitely not worth it unless you are trying to go off-grid, but that’s a completely different topic.). That’s obviously gonna decrease your ROI.
But just straight up saying that you doubt whether balcony solar is making its money back is detrimental to the whole cause, especially since there are enough people out there using it that are easily getting their money’s worth.
I feel the 500kw balcony vertical install won’t cover 20% of a household.
That depends on your household, but again - since you were emphasizing ROI - the balcony solar not being able to cover a lot of your consumption means their ROI is better! This does not mean, that one shouldn’t install bigger systems, I’m just trying to convince you, that balcony solar does have a very reasonable ROI in most cases.
