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movax posted:I have a smaller than I’d like Enphase system (on install day, they discovered the roof was measured wider than it was, RIP 3 panels for fire setback) to offset my consumption. It was not a smart financial decision as it’s something like 20+ years to break even, but I work in clean technology, am a nerd and it felt like a tiny way to help offset my impact (even though Seattle is something like 95%+ hydro, IIRC). iq7's are kind of wonky with the batteries. they do work but those 8's play real nice. they're literally the same hardware except for the processor which lets it react to grid conditions appropriately. wait for 3 things: iq8's on the roof, the r3 model of the Enpower transfer switch and the higher capacity batteries which might even be floor mounted. did i mention the enphase batteries are 95lb's each? and that you really want 6 of them for significant backup? oh, 4th thing to wait for: your state to do Connected Solutions so you can get thousands shaved off the cost over the life of it. they discharge the battery and pay you for it e: interesting thing about iq8's: they will not island unless you buy that same Enpower transfer switch for the batteries, at least 2000 for material alone and most of the labor of a battery install for a system that turns off with clouds. madness. Extant Artiodactyl fucked around with this message at 21:12 on May 28, 2022 |
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May 28, 2022 21:10
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I hope this is the right thread for this kind of thing since I see some recent posting about solar systems, but I'm curious if anyone can point out any red flags in my DIY solar project. I'm looking to make a solar system for my parent's cabin. This is a 100% off the grid place, no running water, will never have electrical hookups, etc. At the moment there is power from 1x 100w panel going into a PWM controller and 2x 12v 100ah batteries which I put together and installed for them. This gives all the power ever needed to run the lights at night, and charge people's phones, run small fans, etc (there are 12v USB outlets, and circular car outlets inside). They also have a small 2200w generator which goes into a completely separate circuit (theres no chance at all of cross connecting things between the 12v wiring inside, and the 120v wiring), split into 2x 15a ones in a little breaker box. This powers a small AC unit on really hot summer days, coffee machine, a TV, vacuum etc when needed. I've had the idea for a while and finally want to act on it, to add a solar system that can mostly replace the generator, as I hate the idea of consumable fuels, and they would have 120v power available without having to go start the generator. To simplify things I'm not going to touch the cabin wiring, so all the lights, phone chargers, etc will still run on the isolated 12v circuit, the solar system will just plug into the 30a RV plug the generator now plugs into to do the 120v activities. This will also let them plug in and use the generator if there isn't power available in the solar system. This is a real rinky dink DIY log cabin, thats been added onto and onto for decades, and no one is looking to do some extravagant build, BUT I have a very very healthy fear of electricity and how much it wants to kill you. This wasn't as much of a big deal with the one little 100w panel at ~20v and 5amp or so, but with this bigger build, that can scale up higher, I want to make sure I've crossed every T, dotted every i, and that I don't have any red flags. I've been doing months of research on all this, solar systems configurations, controllers, wire sizing, etc. On that note a lot of the wiring is over designed for what It could probably get away with (at least i think so...), but I'd prefer to err on the side of caution and have margins for any future expansion. This is a diagram I did of how I envision the system, though I plan to only start with 2x series of 4 panels for 800w total, but I wanted space to expand it in the future if it proves successful:  If anyone has any opinions on red flags I'm missing here, please call me a loving dumbass for dancing with the electricity gods and let me know, or even just any advice/suggestions for things I'm looking at wrong.
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May 28, 2022 23:51
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Tom Guycot posted:I hope this is the right thread for this kind of thing since I see some recent posting about solar systems, but I'm curious if anyone can point out any red flags in my DIY solar project. I'm looking to make a solar system for my parent's cabin. This is a 100% off the grid place, no running water, will never have electrical hookups, etc. This seems OK. I would ensure that you're breaking both legs on your circuit protection devices, and not just the + all the time. Fuse both the + and - of the panels, definitely both the + and - of the batteries, and use a breaker that's DC-rated for the maximum current your system can supply before your inverter. Rest of it seems solid; good job.
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May 29, 2022 04:18
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Tom Guycot posted:If anyone has any opinions on red flags I'm missing here, please call me a loving dumbass for dancing with the electricity gods and let me know, or even just any advice/suggestions for things I'm looking at wrong. Just tips and tricks since an actual person who knows what they are doing has commented on your picture - have you ever wired up a high voltage/current DC system? You're going to want to keep some blankets around to cover your panels while doing the hookups so they aren't producing while you are messing around - remember it's a chemical reaction. I think they make specific things, but soft moving/furniture blankets should be fine. Once you have your strings hooked up you should be fine. Remember not to become a path to ground. How are you planning on racking and mounting this stuff? I would just love to see this setup in general. I would get the batteries up off the ground in a rack of some sort, and strap them down. If they're going to be inside or at least directly accessible/attached to the primary building consider a polypropylene tray and acid neutralizing pads, or a BIG box of baking soda. PIG pads seem to be pretty spendy, and you definitely don't need a 50 pack. If it's in an outbuilding I would store a couple of the like 10lb boxes of baking soda. It's a couple of bucks, and if a battery decides to boil over you will be glad you have it as a way to turn a big pool of acid into neutralized slurry. Heck I bet those pig pads are just doggy piddle pads impregnated with baking soda.  I only suggest spill control stuff because you're _so_ remote. Don't breathe the H2S they let off it's very bad for you.Remember you need to ventilate this room. I don't care how sealed the batteries are, slap a low vent on the door and a high vent on the opposite side of the room, you just need a basic convection draft. If they have vent tubes, which are just a few mm OD, loosely zip tie them together and extend them out away from your living space. If it gets hot where you are putting these you might need a little fan just to pull the draft, but try to make passive convection your friend. Set a calendar reminder in your phone to annually isolate the batteries (turn off both disconnects) and unstring them, test their voltage, clean their terminals, and generally inspect them for premature wear. They shouldn't be bulging, warmer than the rest, or showing excessive (or really any) corrosion. Buy a tube of dielectric terminal grease and leave it on site. At 5 years you need to be considering replacement, at 7 years just do it. Or at least test fire your generator. If you want to do a load test, string them back up, hook up your meter, and turn on the load (house), and then turn on a space heater or something to max, maybe two. If your voltage drops more than it did the year prior you might have a cell starting to go in one of your batteries. Note this down in a notebook you leave on the rack with your equipment. You will thank me if one day your usual 26V nominal string that goes to 25.5V dips to 23.5V under the same load. I'm just making those numbers up, but it can help you get ahead of problems before they ruin a weekend. https://www.autozone.com/greases-and-gear-oil/dielectric-grease/p/permatex-dielectric-tune-up-grease-3oz/34495_0_0 (I think this is right, you want the tube not the little "so you're changing your car battery" packet.) https://www.amazon.com/HAMMER-Baking-Soda-13-5-Pound/dp/B002SKVZIQ (Get this at a bulk discount store in the laundry section. If a battery _goes_ you will be using the whole box don't be shy.) Overkill? Probably. I just like people to be prepared with their dumb ideas.
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May 29, 2022 05:19
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IOwnCalculus posted:I have zero experience with Challenger breakers but all the hits I found on Google pointed at the bankruptcy as being largely the result of poor breakers, though apparently the issue is limited to just the breakers and the main panel itself is serviceable. So I had my AC breaker trip at my apt today (power issues - power went off/on rapidly a few times, then tripped out at the poco level.. then you could tell an auto recloser was trying to do its job when it finally tripped, but failed, killing it for a bit - AC obviously didn't like the rapid cycling/fluctuation before the initial trip). Either someone was sitting on a stack of NOS Challenger panels, or they didn't go bankrupt as early as I thought (this place was built in 1998). It's a mix of Challenger and Cutler-Hammer breakers that look identical except for the name on them, right down to the font and drywall mud overspray on the breakers. The Mikeholt forums say 94+ Challenger stuff is all Bryant or CH stuff and safe?  I live next door to city hall, and their lights go out at the same time - we've had random power issues for a few days since a storm rolled through. I'm a bit surprised it's not fixed yet, esp since our 911 dispatch center is a stone's throw from my driveway. If my ceiling fan shutting off doesn't wake me up, city hall's generator firing up definitely will. My proximity is also probably why I only lost power for a few minutes here and there during last February's ERCOTolypse<tm>, instead of rolling blackouts (like my entire suburb, save for roughly a mile on my side of the street) or just out for a week (most of Austin and much of Texas).
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May 29, 2022 08:51
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General question for anyone - What's happening in this setup to require larger and larger gauge wire? An MPPT doesn't put out more power than it's fed, right? How much power do the batteries put out at once? I have no background in any of this, so if the questions are dumb, sorry.
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May 29, 2022 12:59
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Slugworth posted:General question for anyone - What's happening in this setup to require larger and larger gauge wire? An MPPT doesn't put out more power than it's fed, right? How much power do the batteries put out at once? I have no background in any of this, so if the questions are dumb, sorry. Wire size is rated for the capacity the system can provide until the means of overcurrent protection. The panels are physically incapable of providing more current than they're rated for, due to physics. The batteries, however, will have a short-circuit capability in the hundreds to thousands of amps, so the wire is sized for that until the breaker.
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May 29, 2022 13:44
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Slugworth posted:General question for anyone - What's happening in this setup to require larger and larger gauge wire? An MPPT doesn't put out more power than it's fed, right? How much power do the batteries put out at once? I have no background in any of this, so if the questions are dumb, sorry. I'm not sure why the wire gauge is getting larger on the DC side, but the voltage from solar panel strings can be surprisingly high, which means the amperage is lower doesn't require as large of a gauge.
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May 29, 2022 14:55
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Danhenge posted:I'm not sure why the wire gauge is getting larger on the DC side, but the voltage from solar panel strings can be surprisingly high, which means the amperage is lower doesn't require as large of a gauge. Fundamentally, wire acts as a resistive heater, so the thing you're "sizing the wire for" is the total dissipated power, which is based on the wire's resistance. However, power dissipated goes up with the square of the current. P= I2*R. Say your wire has a reistance of 1 ohm. That's roughly 1000 feet of 10awg, so a 500' run. Say you're pushing 1200W through that wire. At 120V, you need 10A; so you get 100 watts dissipated in the wire. You put 1300W in at one end to get 1200W out at the other. The rest heats your wire. At 12V, you need 100A, so there's 10,000W dissipated in the wire, so you put 11200W in at one end and got 1200 out at the other (briefly, until the wire evaporates). So you make the wire bigger so you only have .01 ohm of resistance. Now your 100A at 12V still puts 1300W in at one end and gets 1200W out at the other. .01 ohms on 1000 total feet is roughly 1" diameter wire, weighing roughly 1.5 tons. Example exaggerated for effect, but it's why low-voltage wire needs to be much bigger: to get the same power out, more current is required, so the resistive losses in the wire scale geometrically. In this specific case, the 2/0 (00AWG) wire is only for the shortest possible distance where the current involved could evaporate the wire and cause a fire. Once you pass a fuse, the "maximum available current" is the rating of the fuse, so you can use smaller wire sized to your actual load. Once past the inverter, the current is much lower, so the power lost in the wire is much2 smaller, so a smaller-diameter (higher gauge) is usable. It's why i recommended breaking both legs in the battery circuit. With a 60A fuse on each leg, the 2/0 only has to go to the battery cutoff fusible disconnect, instead of all the way to the inverter. At the risk of making this too long or belaboring the point: 1000AH lead-acid batteries will provide 1000A for 1hour. They can probably do 10x that in a short-circuit (maybe 100x). Therefore, 3x in parallel is 30,000A at 24V which is 720kW. That's 70 watts per foot dissipated inside the 2/0 until the fuse can blow. Doesn't take long. babyeatingpsychopath fucked around with this message at 19:26 on May 29, 2022 |
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May 29, 2022 15:52
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babyeatingpsychopath posted:Once past the inverter, the voltage is much lower Voltage past the inverter is 5x higher not lower. (And AC.) To the second point: Large scale energy storage holds FAR more power than you sort of comprehend in your head. Ever see someone tap together jumper cables and a shower of sparks come out? This is someone hooking it up wrong (correct: + dead, + jump, - jump, - dead) they should never be holding two leads that spark. They are literally risking the thick copper clamps in their hands welding together and burning through the wire in a few seconds. However jumper wire generally won't actually evaporate, just become a red hot (bye bye jacket) car torching wire. In a dead short the chemical reaction inside the battery can go extremely fast so you can yank out enough amps (600+a @12vdc) to turn over the crank, flywheel, pistons, and push against the compression of the cylinder to start your car. It is also heating up when this happens. If you do it too long the liquid battery acid will boil and explode out of the battery. This is somewhere above 100C and below 300C (it's mixed with water). Then you have 100C 0.8ph solution boiling on the floor and every surface between the battery and the floor. High capacity DC systems are nutso. Our friendly solar poster is stringing together a 24vdc system with 3000 amp-hours of juice.  This is why storage is hard.
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May 29, 2022 16:29
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H110Hawk posted:Voltage past the inverter is 5x higher not lower. (And AC.) Meant Current, not Voltage. Good catch (edited). Also worth pointing out that lead-acid batteries are positively subtle and sedate when it comes to dead-short conditions. The battery boils and pops, spraying hot, pressurized acid everywhere, and perhaps there's a bit of a hydrogen explosion. Then it's done with its drama. Lithium batteries just catch fire in a way that makes the fire hot enough that spraying water on it breaks the water apart, which immediately recombines in a hydrogen-oxygen flame, making everything so much worse. Cover the whole thing in a few feet of sand bad. Bad enough that, if it were a car, the easiest way to extinguish is to drop the car into a dumpster full of water and just let it soak for HOURS. If those are dirt-quality cheap-rear end batteries, then you will be able to pull out 3000A for an entire hour without any component of the system being stressed. If they're good batteries, then you can probably do 8000A for half an hour, or 100A for 100 hours. A hundred amps, continuously, for four straight days. And that's within limits: that's what they're DESIGNED to do. Storage is hard.
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May 29, 2022 19:34
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Worth mentioning that when messing with lead-acid batteries (even just charging, dis(connecting) clamps), you should always be wearing safety glasses. Just a small amount of hydrogen trapped in the battery catching a spark can blast pieces of the battery plastic everywhere. It's not going to kill you, but that plastic flying into your eye can easily take it out. The vents are designed to, but don't always prevent a backdraft into the cell's headspace, which might contain an explosive mixture.
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May 30, 2022 02:44
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Thanks for all the responses! I really appreciate all the advice.babyeatingpsychopath posted:This seems OK. I would ensure that you're breaking both legs on your circuit protection devices, and not just the + all the time. Fuse both the + and - of the panels, definitely both the + and - of the batteries, and use a breaker that's DC-rated for the maximum current your system can supply before your inverter. So, to make sure i'm understanding correctly, all the places I have fuses or a breaker just on the positive line, i should put another fuse/breaker of the same capacity on the negative side as well? So for example I have in my spreadsheet of all the parts i'm looking to get the 200a DC breaker to go on the positive line between the batteries and the inverter, I should buy a second identical breaker to go on the negative line? and do the same for the other spots? Also, when you say 'a breaker thats dc-rated for the maximum current to the inverter' I'm a bit confused, as I was understanding it, the breaker between the batteries and the inverter sizing should be based on the inverters watts/batt voltage, with a 1.25 safety factor, so 3000w/24v * 1.25 puts that at a 156amp breaker, and rounding that up getting a 200a breaker there. Is that not correct? What should I be sizing that one on then? H110Hawk posted:Just tips and tricks since an actual person who knows what they are doing has commented on your picture - have you ever wired up a high voltage/current DC system? You're going to want to keep some blankets around to cover your panels while doing the hookups so they aren't producing while you are messing around - remember it's a chemical reaction. I think they make specific things, but soft moving/furniture blankets should be fine. Once you have your strings hooked up you should be fine. Remember not to become a path to ground. Thanks! Thats some super helpful advice on the batteries and their maintenance, and I added those links to my spreatsheet to look at later. I already planned to put all the batteries and inverter, and well... everything, out in a shed thats next to where the panels would go as I wanted to at the very least physically isolate everything away from the cabin. I know theres vents up near the ceiling, but thats a good idea to make sure its vented down below too, and I was looking at doing a little hood with a fan over the charge controller and inverter to take away heat if it needs it, so it sounds like I may want to do that too over the batteries. My original idea was I wanted to sort of build a shallow insulated tub around where the batteries would go to insulate them in the winter, and it sounds like I need to make that tub idea a lot more robust. Thanks! As far as the mounting for the panels, they're going to go on a treated wooden A frame stand of sorts, like the one I built for the existing panel, but lengthened, anchored into the ground, and with a heavy beam across the top to try and mitigate any trees that might fall over on it. Nothing fancy there. babyeatingpsychopath posted:Meant Current, not Voltage. Good catch (edited). I haven't decided on what type of batteries to use yet, though with as cold as it gets there in the winter i've been thinking li-on is pretty much out. Some kind of battery warmer idea was getting things too complicated. I'm still not sure on if those sealed, or gel, or just traditional lead acid will be better and which to go with, let alone which brand. I've seen some of those big all in one high capacity units and stuff but they really just seem to get way too expensive compared to just putting together a bank. On your last point, I'm a bit confused on what that means, does that mean the batteries will fail if under a load of 100A after those 4 days? What, I guess is what i'm trying to come up with the words for, what is the "safe" continuous draw you could pull from the batteries of a 300ah*24v system with good batteries? At what point does it become a ticking bomb?
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May 30, 2022 03:47
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Tom Guycot posted:
Bigger LiFePo4 batteries now can handle below freezing operation down to like, -10°C, 14°F. As far as heating them, just a regular 120v heating pad for plants and a controller. They typically draw about 20w/hr, a controller will kick them on/off at temps you can set. They're around $50 with a controller on amazon, very unlikely to catch fire, make sure they're UL listed. The problem with freezing temps now is a lot of MPPT controller/inverters don't like working below that. At some point my friend will be installing all of his lithium poo poo to replace his SLAs. He has 10 SLAs the previous owner left behind, varying amperages. The trouble with SLA is you can't use the full capacity without hitting undervoltage cutoffs. Something like half the amperage can't be tapped because of the voltage drop during use. These batteries are about $1800/ea after delivery:  They're available in 24v (200a) and 48v (100a) so approximately 5kw of storage each, at Signature Solar (google). You don't need the rack, it's just helps make it look nice. That combined with a Growatt MPPT (and all the fun switches, combiner boxes, conduit, panels, wire, etc) is becoming a very basic LiFePo4 setup. I'll probably be posting questions for my friend whenever he gets off his rear end and tells me we're hooking everything up. His batteries are in the shed, but he wants to set up the Growatt in the house (it hit -30°F~ a couple times this past winter), so we have to run 40~ feet of DC wire for 48v (anyone know what gauge that is off hand?) and he gets to learn first hand what voltage drop is. I know we're digging the trench and running the conduit this week, wiring maybe next week. Also there's a guy on youtube named Will Prowse that covers this poo poo a lot, but he occasionally butts in a word or two about his Tesla or whatever he's driving that week. You should check out his channel. Here's a video: https://www.youtube.com/watch?v=adFGmOlDM-Y E: also you'll want an MPPT because of the sine wave. Cheap inverters put out a modulated sine wave and it can gently caress up sensitive electronics over time. So don't go buying a Harbor Freight inverter. CRUSTY MINGE fucked around with this message at 04:19 on May 30, 2022 |
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May 30, 2022 04:14
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CRUSTY MINGE posted:These batteries are about $1800/ea after delivery: It’s crazy how cheap commercial electricity is and how expensive storage is. Eighteen hundred dollars worth of batteries storing less than one dollar worth of electricity.
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May 30, 2022 06:07
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babyeatingpsychopath posted:OK. So, this is fantastic, and touches many things I want to know. At this point, I sort of feel like I'm ready to window-shop some of the actual hardware. My goal is more like your first example: switch to demand-based billing, build maybe 12kwh of storage, fed via solar, cheap grid, and maybe tiny little wind-turbine (*). I want my system to prioritize feeding my house during peak loads, charge itself when it's cheap to do so, and run maybe 2-3kw of loads scattered about the house during power outages (meaning, putting all those loads on a subpanel is likely infeasible). I understand I'll have to load-shed, either manually or with smart devices, if I'm transferred to myself. I plan to get an EV within the next 1-4 years, so being able to tap a few kWh of juice out if I need to charge mid-day would be nice too. If it makes it easier: I don't care about backfeeding the grid, just offsetting my draw down to $0 when possible. If backfeeding is something I can toggle on or off, why not, but I don't care to build my system to support that. I'm totally comfortable with the battery side, I understand the chemistries, balancing, and BMSes. I understand the wire gauges, proper crimping, breakers, etc. If it's <= 48v, I'm good. My understanding is that an MPPT charge controller is fed by solar panels and finds the optimum load for them. It then charges my rack of batteries, and inverter-powers the house, which through electro-wizardry somehow makes the house preferentially run from my inverter instead of the grid. I'm totally lost on how to blend multiple generation sources -- can I just daisy-chain different MPPTs with their own batteries and use my house's electrical as "the grid"? Can I put a 500w wind turbine on a 600w wind MPPT with some 12v lithiums, and have that work in tandem with a 5kw MPPT running off of 24 solar panels, and a 12kWh lifepo4 stack? My installation plan is a 50-80A subpanel in the garage to tie the inverters into, and feed an L2 EV charger. This panel would be installed by a professional. The ATS would go between my meter and main panel, so the whole house is isolated during grid outages not just that subpanel. The subpanel is intended entirely to give me a safer place to mount the inverters and keep the L2 charger near the car. I've been following a lot of Will Prowse too, but most of his products revolve around off-grid applications, and I don't know how much they apply to what I want to do. * I don't understand what I need to do to get 240v split-phase power. * I don't understand how to let the inverter supplement grid power, unless it does that on its own. * I don't understand how to tell the inverter it's OK to run without grid-tie, unless it does that on its own. * I don't understand how the inverter knows it's OK to go back to grid-tie, unless it does that on its own. If you have any product recommendations that I should look at, I am all ears! 
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May 30, 2022 11:34
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Platystemon posted:It’s crazy how cheap commercial electricity is and how expensive storage is. Yeah, but when the nearest power pole is a mile and a half away, and the power company wants drat near $3k per pole to get to you, an $1800 battery and $900 inverter is a lot cheaper than slapping poles in the ground. I don't know exactly what Xcel quoted my friend at, but my apprentice neighbor said it's probably 20-30 poles to my friend's house from the current nearest pole. I'd shell out the money for batteries too, if that was the option. Those batteries have 10+ year warranties. E: electric is cheap here too, which is an extra kick in the balls to my friend. I use about 7-8kw a day at my apartment, bill is $30~/mo. CRUSTY MINGE fucked around with this message at 13:37 on May 30, 2022 |
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May 30, 2022 13:31
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CRUSTY MINGE posted:Yeah, but when the nearest power pole is a mile and a half away, and the power company wants drat near $3k per pole to get to you, an $1800 battery and $900 inverter is a lot cheaper than slapping poles in the ground. At that rate it might be a lot cheaper to put the wire in the ground instead of on poles, or is there something preventing that? Super rocky ground/swamp etc?
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May 30, 2022 14:49
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Rakeris posted:At that rate it might be a lot cheaper to put the wire in the ground instead of on poles, or is there something preventing that? Super rocky ground/swamp etc? Nah, it's mostly sand. There just aren't enough people that live down his road to justify the cost to the county (his road is also dirt), and everyone out there has panels. (E: maybe a little swampy, the water plate is around 20 feet down and there are wetlands in the region). Even burying cable, it would still be more costly than doing an off grid setup. His house is 750ft~ from the road, too. There are no phone lines out there either, they stop where power stops. He's got about $6k in solar stuff between the batteries, Growatt, and all the poo poo he had shipped to my apartment (conduit, switches, combiner box) and that sets him up at 10kw. He plans to add one more battery this year and probably spend another $1k on more panels, then 3 more batteries when he's ready to put on his addition. Even if he dumps another $10k into his solar, it'd still be a fraction of what it would cost to have Xcel set him up with a grid connection, so why pay more to pay a monthly bill when you can just go off grid?
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May 30, 2022 15:01
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I have been starting to think about pricing out a solar roof installation for my house, and had a question. I might be needing/getting a new roof installed in the near future. Is there any savings in trying to get the solar installed at the same time as a new roof? I have two layers on my current roof, so it would definitely be a tear off. And knowing that my roof did not have the life left of payback on a solar installation is what kept me from looking in to it until now. I figured I didn’t want to deal with the cost/hassle of disassembling the whole system in 1-5 years from install. I am also guessing that the solar installers getting in the way and holding up the roofers is more of a headache than it is worth. But I will probably be getting roof and siding from the same company (siding is the main driver of the project), so there might be some wiggle room on timing if weather plays nice in Northern Illinois (lol, no chance).
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May 30, 2022 15:59
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There is no way to parrallelize the work - it's serial. Have a roof put on and then have solar put on the new roof. There is a chance that your roofer will be a solar installer as well, but you should be evaluating those thing separately. I wouldn't double up unless you can get some really great reviews and go look at their work (from the street.)
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May 30, 2022 16:36
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Tom Guycot posted:Thanks for all the responses! I really appreciate all the advice. Note that, like with all electricity, you must have a complete circuit, and current flows in all conductors of that circuit. It's possible to have the - wire be the faulted one, and you'll still get massive current -- except that current must now go through all the devices in order to blow the fuse on the + wire. There's no reason NOT to fuse both lines. Use 2-pole fuseholders on everything, and 2 fuses. DC fuses can be very small even at extremely high current ratings, so it's not much space. A single-pole fuseholder is $30 and the fuse is $3. A two-pole fuseholder is $40, and two fuses is $6. As far as the breaker, here's a "find this at Home Depot" breaker: Example link. Note that the "voltage range" is 120/240VAC. It is not rated for DC at all. It is not designed to interrupt DC current, and may fail to trip, fail to open, or explode if used to interrupt DC current. However, a breaker like this is rated "120/240VAC, 120VAC, 48VDC" and will properly interrupt DC current. It's not sizing, it's rating. Sizing all comes out of the applicable sections of the NEC. To the last point, it's a battery. If you have a AA battery that says "1250mAH" then you can pull 125mA out of it for 10 hours, then it's discharged. You have to recharge it now. Same with your batteries. 300AH of capacity gives you 300A for an hour, or 30A for 10-15H, or 3000A for a couple minutes, or 30,000A for a few seconds. Then the battery is dead and needs to be recharged. If your BMS is at all intelligent, it will be connecting and disconnecting batteries as the voltage indicates charged/discharged depending on whether or not you're asking for or supplying power. Which, I just noticed, you don't have at all, unless your MPPT has integrated battery management. Once you've selected equipment but before purchase, look at the equipments' install sheets and see what their recommended wiring is. There are some installations that want fusing on the input and output, some on the input only, and some on the output only. Regardless, check in the "rated voltage" section of everything and make sure it specifically says 24VDC or more. 120VAC is not more than any VDC; it's not the same kind of voltage, and a VAC rating does not compare in any way to a VDC rating.
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May 30, 2022 16:37
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H110Hawk posted:There is no way to parrallelize the work - it's serial. Have a roof put on and then have solar put on the new roof. There is a chance that your roofer will be a solar installer as well, but you should be evaluating those thing separately. I wouldn't double up unless you can get some really great reviews and go look at their work (from the street.) That’s what I figured, but thought it best to check an outside source before a contractor spun me tales. Thanks. Edit/ At least the roofing/siding contractor is a known quantity, as my wife has used this company a bunch for her work. It will just be seeing what options are available in the area for the solar install. Orvin fucked around with this message at 17:26 on May 30, 2022 |
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May 30, 2022 17:10
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CRUSTY MINGE posted:I'll probably be posting questions for my friend whenever he gets off his rear end and tells me we're hooking everything up. His batteries are in the shed, but he wants to set up the Growatt in the house (it hit -30°F~ a couple times this past winter), so we have to run 40~ feet of DC wire for 48v (anyone know what gauge that is off hand?) and he gets to learn first hand what voltage drop is. I know we're digging the trench and running the conduit this week, wiring maybe next week. This https://www.omnicalculator.com/physics/dc-wire-size calculator says 1 AWG for 48V, DC, 100a, 40', assuming max 3% voltage drop.
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May 30, 2022 17:14
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babyeatingpsychopath posted:To the last point, it's a battery. If you have a AA battery that says "1250mAH" then you can pull 125mA out of it for 10 hours, then it's discharged. You have to recharge it now. Same with your batteries. 300AH of capacity gives you 300A for an hour, or 30A for 10-15H, or 3000A for a couple minutes, or 30,000A for a few seconds. Then the battery is dead and needs to be recharged. If your BMS is at all intelligent, it will be connecting and disconnecting batteries as the voltage indicates charged/discharged depending on whether or not you're asking for or supplying power. Which, I just noticed, you don't have at all, unless your MPPT has integrated battery management. Two caveats to this: First, larger batteries sometimes have "safe" discharge rates that are some fraction of the total AH of the battery, usually talked about in terms of "C", which is the rate that will discharge the battery in an hour. So a 300ah battery you can discharge at 1C you can discharge at 300 amps, whereas a 300ah battery with a safe discharge rate of 0.5C you want to avoid discharging at more than 150 amps at any given time. Most batteries should tell you the discharge rate that will not lead to significant degradation. Secondly, lead acid batteries you typically never want to take to more than 50% depth of discharge, so a lead acid battery will have an effective AH rating of 50% of the listed value. You can discharge lower in a pinch, but it will speed up their degradation and mean you have to replace the battery sooner.
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May 30, 2022 17:18
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Orvin posted:That’s what I figured, but thought it best to check an outside source before a contractor spun me tales. Thanks. That is great, and having a commercial relationship can really be great should anything go wrong. If they are also a reputable commercial solar installer I would seriously consider them for both elements. If they aren't they should decline the work regardless to not harm the commercial relationship.
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May 30, 2022 17:37
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Alarbus posted:This https://www.omnicalculator.com/physics/dc-wire-size calculator says 1 AWG for 48V, DC, 100a, 40', assuming max 3% voltage drop. Thank you, I need to bookmark that page.
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May 30, 2022 19:23
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CRUSTY MINGE posted:Nah, it's mostly sand. There just aren't enough people that live down his road to justify the cost to the county (his road is also dirt), and everyone out there has panels. (E: maybe a little swampy, the water plate is around 20 feet down and there are wetlands in the region). Yeah makes sense, I'm really surprised by the cost of the grid extension, used to do them inground pretty often when working excavation, it has been like 8 years but then it was like $1.25 a foot + $2 a foot for cable, and the local distro company would come out and drop a transformer and hook it all up for another $500. People hired us to do them because it was a fraction of the cost of having the electric company do it, we would get hired for entire subdivisions and poo poo. Inflation is a mofo. Rakeris fucked around with this message at 21:10 on May 30, 2022 |
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May 30, 2022 21:05
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Danhenge posted:Two caveats to this: First, larger batteries sometimes have "safe" discharge rates that are some fraction of the total AH of the battery, usually talked about in terms of "C", which is the rate that will discharge the battery in an hour. So a 300ah battery you can discharge at 1C you can discharge at 300 amps, whereas a 300ah battery with a safe discharge rate of 0.5C you want to avoid discharging at more than 150 amps at any given time. Most batteries should tell you the discharge rate that will not lead to significant degradation. Oh yeah, there are whole worlds about how to use batteries. High-current starting batteries that can discharge at 300C, deeeep-cycle batteries whose on-the-cover rating is actually the rated voltage down to 12.4V, and not the actual "100% depth of discharge." There are pages and pages that come with storage batteries that tell you how long you can expect them to last based on time, temperature, depth of discharge, and charge rate. For example, there are "solar batteries" that are specifically marketed for this segment. If you take 120hours to discharge them, you get 120AH (1 amp continuous for 120 hours). That exact same battery is only rated for 100AH if you discharge it in 10 hours (10 amps continuous for 10 hours). So going more slowly gives more capacity. This is going down to 50% DOD (12.3VDC/2.05VPC). You can actually get 240AH out at 1A continuous if you go all the way down to 1.75VPC, but that halves the battery life every time you do it. That is, the battery is rated for 2400 cycles going down to 20% DOD (12.6V), 1400 cycles at 50% (12.3VDC), and 700cycles at 60+% (<12.2VDC). Other specific manufacturers have similar ratings/specifications, and it's up to the installer to determine what their system needs. To harp on the short-circuit thing a bit, that battery above will source ~3000A for just shy of two minutes before it's down below 10V.
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May 30, 2022 21:50
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Rakeris posted:Yeah makes sense, I'm really surprised by the cost of the grid extension, used to do them inground pretty often when working excavation, it has been like 8 years but then it was like $1.25 a foot + $2 a foot for cable, and the local distro company would come out and drop a transformer and hook it all up for another $500. People hired us to do them because it was a fraction of the cost of having the electric company do it, we would get hired for entire subdivisions and poo poo. Inflation is a mofo. I'll ask my apprentice neighbor about underground rates next time I see him, but even at the rates you're familiar with, it would still be pretty expensive. They do bury plenty of wire here, but 8 miles out of town, it'd just be faster/easier to pump poles into the ground for the half dozen houses down his stretch of road. He's closer to two miles away from a pole than one, it'd still be $30k+ to get grid power to his house. And then he'd have to pay a bill.
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May 30, 2022 23:37
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CRUSTY MINGE posted:I'll ask my apprentice neighbor about underground rates next time I see him, but even at the rates you're familiar with, it would still be pretty expensive. They do bury plenty of wire here, but 8 miles out of town, it'd just be faster/easier to pump poles into the ground for the half dozen houses down his stretch of road. Ooooh, I thought you meant he was just 750ft away, probably should have read the previous posts, my bad. But yeah even at the rates I was familiar with probably looking at a fair bit more, and I'm sure wire is a decent bit more expensive now, even if the labor is the same.
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May 31, 2022 00:10
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Oh, no, 750ft to the dirt road, then 1.5-2 miles from the nearest pole. He's definitely one of those cases where off grid solar is about the only viable, affordable option. He's looked at little wind turbines too, it's blustery as gently caress up here, but I've convinced him against it because sand will destroy the drat thing. He's on his third wind speed indicator in a year.
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May 31, 2022 00:53
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CRUSTY MINGE posted:Oh, no, 750ft to the dirt road, then 1.5-2 miles from the nearest pole. Sorry but just for my own learning - what's the reason for having a wind speed indicator? Just funsies or why have one? I only ask because if he's replacing them seemingly as soon as they fail there must be some interesting reason he needs one?
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May 31, 2022 01:54
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They're just little weather stations from amazon. The PO left a new-ish one that burnt out before winter. He replaced it with another cheap one, and he got a nicer one as a gift for a backup, which he's already using. He just has an interest in it. There's nothing out there to stop the wind, so you can hear it easily in the house. It's been 25-35mph winds a lot lately, gusts in the 50s, but what kills them is sand getting anywhere near the rotating bits.
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May 31, 2022 02:06
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CRUSTY MINGE posted:He's closer to two miles away from a pole than one, it'd still be $30k+ to get grid power to his house. And then he'd have to pay a bill.  “Look at what they’ve done to my legacy.” CRUSTY MINGE posted:He just has an interest in it. There's nothing out there to stop the wind, so you can hear it easily in the house. It's been 25-35mph winds a lot lately, gusts in the 50s, but what kills them is sand getting anywhere near the rotating bits. I would suggest a hot wire anemometer, but AFAICT no one sells them in hobbyist weather stations.
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May 31, 2022 02:13
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Platystemon posted:I would suggest a hot wire anemometer, but AFAICT no one sells them in hobbyist weather stations. He just likes having the basics, so something like $50-80 off amazon fills his needs. At least for now, he might go down a rabbit hole someday. The wind function is pointless out there, it's always windy.
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May 31, 2022 03:50
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Comedy option: point a webcam at this
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May 31, 2022 03:54
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That would look good in his front yard.
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May 31, 2022 04:01
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Welp, the property owners are reporting something... "weird" with our 450' wiring run. As a refresher, I'm taking a 220v from the panel up at the main house. That breaker is a CFCI breaker. It's run through a direct bury cable, to a RV outlet panel down by my cottage. That outlet panel, has the standard 220v RV hookup, and one leg is split off to a GFCI outlet for 110v service. Since I dont' spend a whole lot of time there, the people who live there, are using my wiring run. (I mean, who wouldn't? 110v at a spot on the property that didn't have any?) Another person built an outbuilding, as a home office. They are running a moderate sized LiIon pack, and are in the process of getting solar setup. In the meantime, when he plugs in his charger, it trips the GFCI up at the main panel. But not the GFCI on the RV panel. It also doesn't trip when power tools are used. So perhaps it's just a horrifically noisy PSU on the charger? I suspect, it's because they haven't wired in the local ground for the RV panel. (I haven't been there since they made it live) Platystemon posted:Comedy option: point a webcam at this As somone who's driven through the square states like.. five times in the last couple years. Holy crap is this accurate. I saw double digits of blown over trailers (both RV and cargo) every trip.
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May 31, 2022 06:39
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| # ? May 9, 2024 18:33 |
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The house I bought last year came with a few basic Hampton Bay ceiling fans installed. One of them suddenly stopped responding to its corresponding light switch and its remote control. What electrical troubleshooting can I do to diagnose the problem before just going out and getting a replacement? Everything else in the room works and there's still a readable voltage at the switch.
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Jun 6, 2022 04:57
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