Nerdishness and Solar power
- Thread starter Pfitzy
- Start date
boyo
Mark Ella (57)
AFAIK solar panels work by converting light into electricity. That is why they still work on cloudy days, but not as well.
blindsider
Billy Sheehan (19)
Have you got an e-gauge @pfitzy
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Sent from my iPhone using Tapatalk
terry j
Ron Walden (29)
that was great oz. I'll watch the rest of the series for kicks.
So pfitzy, leaving aside cost of the powerwalls, what is the max size powerwall you could realistically charge with your array? I assume you fully charge your battery array atm, ie the amount of charge you get in your batteries is limited (due to cost of the powerwall/s) by battery size rather than charging capacity?
So pfitzy, leaving aside cost of the powerwalls, what is the max size powerwall you could realistically charge with your array? I assume you fully charge your battery array atm, ie the amount of charge you get in your batteries is limited (due to cost of the powerwall/s) by battery size rather than charging capacity?
Pfitzy
George Gregan (70)
There are a few factors in this, not all of them technical:
1) Some areas of the power network have limits on the size of the grid-connected system you can attach. For example I believe in NSW less than 10kW is the maximum domestic system allowed (twice the size of mine), and then network distributors have a limit per phase (e.g. 5kW for a single-phase).
2) Physically the Powerwall can only accept a maximum input of 3.3kW peak - and it generally won't sustain that for long in practical terms. Standard flow is 2kW, and if I had multiple Powerwalls chained together, I'd still only be able to push about 2kW through to the whole array because they're in series, not parallel
3) To get around this, I could install a second system that ONLY charges batteries - the way around the limits in Point 1 is to install a system that ONLY pushes DC into the battery. Because that limit only applies to on-grid systems, I could have one whole 5kW array (or bigger) just feeding the batteries all day, without any grid connection, and leave my existing system powering the house and pushing into the grid.
4) That takes away a little from the warranty of the Powerwall (10 years grid, 4 years off-grid) so I would look at another battery to do that. Check out http://redflow.com/ for the primary manufacturer of Zinc-Bromine power cells. Already heavily used in industry for remote sites, there are pros and cons over lithium. Downside of the zinc-bromine solution is that the liquid needs cycling once the unit is drained, which takes 30-60 minutes I'm told. Also has a service limit between 10-50C (because its fluid) which isn't great in Australia unless you've got decent insulation.
With all that in mind, my dream scenario is this when I win a shitload of cash:
- Build an earth-sheltered house with a room full of Zinc-Bromine batteries in the cellar (accessed by tunnel) to a sleepy 18C
- Stick a massive solar array on top of all that with appropriate inverter technology and enough juice available to power up my Tesla Model S or X
- Water tanks and suitable filters stored in the hill I build into for drinking, cleaning, and fire prevention.
Basically a luxurious bunker with a gorgeous outlook over a valley somewhere, and no real danger of bushfire. The Zinc-Bromine cycling issue is taken care of with multiple batteries in parallel, and with low-use appliances and a crapload of available panel generation, I'm all good.
Pfitzy
George Gregan (70)
spam
Mate of mine is doing some renovations, including excavating a big-arse hole in the ground for a 3-4 car underground garage. Being built with Tesla charger and Powerwall set-up ready to go. Now I just gotta see which Tesla he gets!
Dismal Pillock
Simon Poidevin (60)
41 degrees? Thats damn near 60 DEGREES CELSIUS hotter than where i am here! wft.
No wonder Pfitzy's so clued up about all this sun shit, he lives right on the fucker.
Have you locked yourself in the fridge again? You know it shrinks your nuts PERMANENTLY! Permafrost fucking raisins for you, my man. The Pillock line ends with you.
Dismal Pillock
Simon Poidevin (60)
ha, reminds me of an old comic strip i once ruined. So that homestay guest who stayed in the fridge was Pfitzy? shit i had no idea!
Teh Other Dave
Alan Cameron (40)
Orthopod, or radiologist?
terry j
Ron Walden (29)
now having removed it the drawback is revealed, I have to scroll right up the top to see what you wrote!
Thanks, as always, for the detailed reply. I must confess that the blog post I suspected was not you, till you clarified all by admitting you were watching your language, and the heavens were restored to their normal orbit.
Ain't life always complicated?? You obviously gleaned the question i was alluding to (ie offset the cost of the commercial powerwall, prob the single largest individual component cost) by the diy linked to (and what's the bet you would find it hard to source the batteries as described) and build in a much higher battery reserve.
I wonder how soon, and by how much, things like the powerwall will come down in price. I remember even only (five years say) a short time ago I idly pondered making my own solar panels, plenty of tutorials back then how to do it, vacuum your own weather protection, source the individual cells and solder them together etc etc.
you simply would not bother just these few years later, the prices have come down so dramatically it is not worth your time (and get a better result commercially anyway). Such is the speed of change.
Anyways, off to read a little about elon musk!
Neither. Most of mates are NOT medicos.
Dismal Pillock
Simon Poidevin (60)
personally i would have gone with.......http://whitepowerwall.com
goddamn i wish solar energy was known euphemistically / scientifically as "white power." There's white noise, white power makes sense! That could be one of the logo's I'd run with for the thousands upon thousands of homepgaes I7d gladly spend the rest of my days cobbling together under the narrative
"It's not white noise, white power makes sense!"
"White Power, let it shine like the sun!
"Only WHITE POWER can save mankind!"
Teh Other Dave
Alan Cameron (40)
Neither are orthopods or radiologists.
Runner
Nev Cottrell (35)
For more consumer information on the Tesla Powerwall, check out the Choice website.
Pfitzy
George Gregan (70)
I found Choice's calculations to be somewhat pessimistic, because they're really looking at the micro-level finance of it. They came out with a best-case scenario of 14 years, but the focus of their article is "to pay off the powerwall" when in fact it is paying off the entire system.
This "exceeds the warranty" talk is oblique to the actual point: you're not just getting a battery. And while the battery comes with a 10-year warranty, the panels and workmanship often come with something far better (25 and 12 years respectively for me). The only downside is a 5 year inverter warranty (edit: methinks, but know not precisely), but then that affects everyone who gets solar, pretty much.
I assume the guy in the case study couldn't install a bigger system (i.e. 5kW) which would take advantage of the cheaper panels to generate more kWh per diem and change that equation.
So I don't know what Choice's agenda is, but their methodology is flawed. They don't even list the guy's average daily use or what other measures he's going to take to reduce their power use - once you get access to the data, you start to look at your electricity far more critically.
Approaching it from the macro end for a minute, if my system ($15,990) wipes out my usage costs per annum ($1930) then ROI is 8.28 years. That becomes the absolute best case, and looking at the current position, maybe unrealistic on my part at today's prices.0
If it wipes out 90%, then ROI is 9.2 years
At 80%, ROI is 10.3 years - only at this point do I exceed battery warranty.
That is not counting any feed-in tariffs, Reposit GridCredits, or calculating for either system efficiency degradation over time or electricity price rises (both of which I accept are inevitable, and one may offset the other).
Yet, in about 4 years' time, when the technology has taken another leap forward, I'd have no issues looking at another battery storage to help reduce my reliance on the grid, even if I don't want to disconnect forever.