> the transfer switch variety switches your house between the inverter and the grid whereas the disconnect just physically disconnects the inverters output
> That simply is a transfer switch that is built in.
Then in this comment:
> but both a transfer switch and a disconnect are the same thing
These statements are false, and the fact that the second one was written even after being corrected once makes me think they still do not understand.
This user appears to blast paragraphs upon paragraphs of irrelevant noise at anyone who responds to them so that either the comment has internal conflicts (as you noticed) or any criticism seems nitpicky.
If you can design and build your own inverter I would take it as read that you know how to read code and know how an actual inverter should function:
If you're grid connected and see valid phase on the input for a certain amount of time of matching phase and measuring voltage you can provisionally connect at exactly that phase and voltage but without injecting power. After that you are allowed to slowly ramp up your output by leading the phase (while raising the voltage within certain limits) as long as you observe the effect that you have on the grid. If the grid phase drops away or there is any other anomaly (such as a voltage drop or rise of more than x V/s you are required to immediately disconnect, there are many other disconnect requirements but that's the main one with respect to line worker safety.
Three disconnects within a short period of time = no reconnect attempts for a much longer time. If the situation persists that's a failure and you are no longer allowed to connect to the grid until there has been an intervention and an inverter reset.
If your inverter is of the islanding variety then the rules are slightly different, then the transfer switch only gets energized when you match voltage and frequency but in the meantime the (usually battery backed up) inverter can supply local consumers.
By the time you come up with the idea of rolling your own inverter you have either become familiar with the requirements (which differ from region to region, and which in a properly designed inverter are mostly a matter of tweaking firmware parameters) or you will have to do so because you realize your responsibilities.
Anybody up for this kind of project will with a high degree of likelihood have the required knowledge because that knowledge is a lot simpler to acquire than the knowledge to build an inverter that isn't going to result in you being laughed out of the room when your EE buddies come look at your creation.
I would expect you to do a better job than 95% of the imported ones that I've taken apart and which all had massive shortcuts taken, good enough to pass first inspection and a year into warranty, not good enough for long term safe deployment. This ranges from unsuitable connectors, low quality inductors, even lower quality relays, undersized FET boards, insufficient cooling, bad cast aluminum housings, in general bad housings (not rodent and/or insect proof) and so on.
Thanks, and I agree that a DIY-inverter designer should be able to meet grid-interconnection requirements (e.g. IEEE 1547-2018). With that said, I think case-by-base evaluation from the AHJ would be prudent without a UL listing... something that AHJs don't want to do.
I'd prefer to just put the DIY inverter behind a transfer switch (with an adequate battery bank and maybe a small propane generator)... with the grid as emergency fallback.
That's exactly the setup that I had in Canada with a windmill thrown in for good measure (which really helped in the winter, after we got the windmill up we never ran the generator again).
Not that this is accepted by insurers or AHJs ("authorities having jurisdiction"), but one can use UL-certified components in an (open-source) _assembly_ that itself isn't UL certified. This at least supports the argument that the overall product is safe if thoughtfully designed and assembled. An example is the OpenEVSE level-2 car charger (which I had a really good experience with).
The creator of OpenClaw, for example, has come to appreciate grammatical / spelling errors in human writing (as he said in a recent Lex Fridman interview).
Loosely related: This Lex Fridman discussion with a nuclear-fusion engineer, about 1-million-amp 100-million-degree electrical systems... blew my mind: https://lexfridman.com/david-kirtley
pretty sure it's an established rule now that drywall cannot be discussed w/o linking to vancouver carpenter.
but, yeah, his videos are great. i've done more than my share of everything from sound abatement channels/glues/etc, hanging rock on vaulted ceilings, to level 5 finishes, but I still like to flip though his videos every now and then and pick up logistical / speed tips.
For me, there's a sharp binary:
If I ask AI to "own" a coding-problem solution — with me passing back the failure responses until resolved — my mind gets numb and I learn nothing.
If I insist on owning the solution — using AI in my effort to better understand the problem space — my mind is active and I get better at coding.
Sometimes I'm lazy and fall into the former. But mostly, so far, the latter.
hydro can win if all the stars align. Electrochemical is the real winner though.
This is just a grift. I doubt this thing will ever materialize. It seems like every month a new gravity storage company emerges and none of them go anywhere with their promises.
As I posted elsewhere, my power company is installing 200MWh of storage on 10 acres. It will take them about 6 months to build it out (they've not started construction yet, they project they'll be finished by june. They just finished getting all the approval they need to start work).
That sort of land efficiency and deployment speed won't be matched by any gravity storage system.
Costwise, it'll probably be in the range of $24,000,000 to install (maybe more like 30M with power electronics requirements).
Complexity is a big part of it along with a lot of required materials.
It takes either a lot of heavy weight or a very long decent regardless the storage system in order to store a significant amount of energy. Further, you need some very beefy generators/motors to work with that weight along with some complex equipment to ultimately convert the AC output into what the grid expects.
It requires 20 acres, a mining pit, 30 employees. And how much energy does it store? 12.5 MWh (15 minutes of runtime, 50MW of output). And do notice the date, 2020. From what I can find, this thing hasn't even started operating yet.
That's a VERY expensive battery which hasn't even been built yet.
All of these very special requirements for such a low storage amount is why these things are grifts.
The comparison is my electric company, which is going to install 200MWh of batteries on 10 acres of available land (it's right next to one of their big substations). It'll take them 6 months to do and the main hurdle they had was getting city approval to start work.
The reason pumped hydro is about the only appealing form of a gravity battery is because you can store just massive amounts of water conveniently which gives those systems pretty nice storage levels. Further, the equipment is near the same of any hydro dam. But even those suffer from very specific geography needs before they can get off the ground and massive amounts of hurdles with local regulations in order to even start work. There is, no joke, a proposed pumped hydro system that I know about which has been in the planning stage for the last 20 years as they've been going back and forth with the local county and community.
That's why it's a grift. The competition is chemical battery storage which has stupidly high energy density and almost instant deployment. Any gravity system that is going to be competitive needs both those things before it'd actually be a contender. I've yet to see any of these systems actually get built beyond just tiny prototypes.
The parent comment's point is that we _should_ care because cheap frontier-model access (that many of us have quickly become hopelessly dependent on) might be temporary.
It's amazing that anyone that has seen anything in technology in the last 30 years can say, "better be careful. They might stop subsidizing this and then it's gunna get expensive!" is ridiculous. I can buy a 1Tb flash drive for $100. Please, even with every reason to amortize the hardware over the longest horizon possible are only going out 6 years. 64K should be enough for anyone right?
Yeah, I can't wait to buy some RAM for my PC! Oh, wait, the AI companies are buying up all the RAM sticks on the planet and driving up their prices to comical highs, surely these beacons of ethics and morality won't do the same with their services that are actively hemorrhaging Billions of dollars, they're providing these services to us out of the goodness of their black hearts and not any kind of monetary incentive after all!
> the transfer switch variety switches your house between the inverter and the grid whereas the disconnect just physically disconnects the inverters output
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