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Post by Nex Socius on Jan 2, 2014 22:36:49 GMT 10
I'm looking at possibly building, so am looking into costing and other things to see if it's worth doing and affordable. One of my goals is to be off grid. Water will be taken care of with tanks and a good catchment system - this I understand. Power, however, is double dutch to me. Here's a lot of (dumb) questions I haven't been able to find the answers for. *I would like a solar system that could happily run my laptop, lighting, 35 watt aquarium filter 24/7, Aquarium chiller 24/7 during summer (Power consumption 120W, refrigerating capacity 85w) and a microwave. It would be a 1 bedroom / 1 - 2 person home, no tv, and probably a pedestal fan or 2. Also, the ability to add an extra of each of the aquarium bits above would be nice down the track (I love my axolotl lol). What would I need for this - how many panels of what size, inverter, batteries, and other thingies? *I'd rather not have to use a genny...if I get more panels and batteries than I need, would this reduce the need for a genny? *Can you power a small stove or oven from solar? Or would gas be a better alternative? *Do solar hot water systems have to be a separate set of panels and system, or can something be integrated into the main solar system? *If you are connected to the grid, but have solar as well (some people feed their solar back into the grid to earn money back), can you switch between the two at will? As in, on cloudy wet days, switch from solar onto the grid, then back to solar? *As for the fridge, I've read the threads on here, and think it would be best if I borrow dads idea - he has a Waeko car fridge in the back of his twincab, powered solely by a panel on the top of the cab. He'd be able to set something up like that - I don't need alot of fridge space. Sorry for the dumb questions, I'm yet to find an informative site with educational content.  |
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Post by Ausprep on Jan 3, 2014 8:07:54 GMT 10
Hey Nex! Ill post my thoughts later on tonight, until then, you may want to have a read over the link below. Some great ideas. www.builditsolar.com/ |
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Post by Nex Socius on Jan 3, 2014 12:03:00 GMT 10
Thanks mate I'll take a look  |
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shinester
Senior Member
China's white trash
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Post by shinester on Jan 13, 2014 4:58:14 GMT 10
Well you'll have to give some power ratings and how long you want to run them for, if you want to run them independently of the grid, to be able to work it out. A 'REALLY' approximate ratting of panels is 10x the wattage if you plan to run them 24/7 and each watt costing about $1 not installed. This takes into account that 1/3 less sun is available in winter time [2.4hrs x the panel rating/day] compared to summer [6.9hrs x the panel rating/day] for Melbourne. You'll get a 'little' more juice the further you go north but it's not a huge amount. So your aquarium filter alone would need 350W of panels, your chiller power 1200W + 850W for the refrigerating, so we're talking 2400W of panels to take care of your fish before we go to your other accessories and the other hardware needed such as batteries [which are really expensive too]. This brings back the reality of solar, it's great for low power applications and every Watt costs you plenty, its best to conserve every single watt you can. If you want long term, you'll be wanting to get rid of almost everything you can depending on priorities. For your application, a Genny [get a good one so it lasts and is reliable] is the best option if you are keen to run all of those things, which would potentially be about 1000W, though work it out, every appliance has a rating on the back in Watts Offtopic - If you like aquariums, check out aquaponics, fish and food. It would depend on your priorities and necessity and time span. For power outages, a freezer containing ice blocks could keep the aquarium cool for a while, and air-pump that uses D batteries that last about 8hrs for your air supply, they're rather cheap ($15) even if you need a couple for the Dissolved Oxygen keeping your fish alive. Whilst it's not ideal, you'd get away with not filtering for a while. If it's SHTF, I think you come before the fish and a genny/fuel or batteries might be better used elsewhere. Solar hot water is a different system, it uses the 'heat' of the sun to warm water within pipes which is then fed into your hot water service saving you gas/electricity. Solar panels [PV] make electricity with the suns light [photons]. You can of course have both systems on a roof and for bill savings, solar hot water gives you the best returns. Think of it this way, the panels electricity is used by the house first. If there's anything left over, that power goes back into the grid and makes your meter run backwards. If it is cloudy then it draws from the grid after it's used whatever it can from the panels. It's all automatic and you can forget about it once installed. Now if you want to run things in your house when the power goes down, then you will also need a battery bank, which are large and really expensive. I'd be checking the panel size, the daily draw the fridge has and working out the ratings as it also could actually be draining the battery overall. Most people well underestimate how much power they need from solar or don't account for winter sun which is 1/3 of that of summer. Having said that, there's my post on doing a solar powered fridge to which a counter real life working example was given and I would follow what he had done. Hope this helps. |
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Jackosaur
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Post by Jackosaur on Jan 21, 2014 11:43:56 GMT 10
I've been thinking about refrigeration on 12V lately but don't know much about solar. I can see some 12V fridges, from BCF for example.
If anyone knows I'd be interested to see a link to a pairing between a little fridge and a suitable solar unit to power the battery so it would provide enough charge to power it overnight until the next days sun.
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Post by pheniox17 on Jan 21, 2014 12:52:01 GMT 10
depends on the fridge?? 12v fridges are easy to power tho, they come with a mass of important info, a data card with relevant numbers based on those numbers most camping stores will have info on what amount of power you need to generate, and what you need to store for overnight my advice, the 12v fridge is very expensive, go with trusted names (like wacol) or you will be getting junk that will drop the temp 10 degrees below ambient (so it's a 30 degree day, fridge will run at 20 degrees) with the actual stats of the fridge we can be more helpful (2 fully charged truck batteries will last 2-3 days on a med/small sizes wacol fridge) |
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shinester
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China's white trash
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Post by shinester on Jan 29, 2014 2:26:45 GMT 10
The good Doc knows how to run a fridge. Follow his example for a working system. I'm probably going to do something similar at some point after some other priorities get taking care of. Hey Guys, I don't mean to throw a spanner in the works here, but we need to look at alternatives for refrigeration if we intend to live off grid or the SHTF! I posted some fridge stuff in DIY section! I have worked out that even for a family of 4, my National Luna fridge freezer is big enough to keep what we need cool and make ice! My NL runs 24/7 from a 200amp battery, with 2x80wat Solar panels! I will still buy a gas/kero fridge but when you look at it, if you have a cool room/cellar and you can fresh food, veggies , meat Etc, you don't need to store large quantities of perishables! Milk and butter will last 1-2 days in the Cool room/cellar Meat that is salted and or smoked will last months just in a cellar! So you don't have to go with out anything! Just sensible prepping! As an extra, I have been looking at building a Wood Gasifier to run a 15kva genset! They used these during the war to run cars, so I started thinking why can't they run a genset with a petrol motor! www.soilandhealth.org/03sov/0302hsted/fema.woodgas.pdfAlso, Browns Gas (hydrogen and O2) generator could run a Genset as well! |
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Post by StepfordRenegade on Jul 4, 2014 8:05:13 GMT 10
Sorry to add my random question to your thread Nex... but I was wondering if the power went down, I know the energy companies have the ability to turn off your solar so they don't get electrocuted when fixing the power lines. So does this mean in a grid-down situation solar panels would be worth nothing unless hooked to a battery bank? Or would the electricity still flow through the house so you could technically get a bit of juice still? |
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Post by graynomad on Jul 4, 2014 10:24:40 GMT 10
Yes it will, but unless you get sun 365 days a year you will always need at least a small gennie if you are totally off grid.
Solar will run these, BUT only if you have a very large system. In general you do not use solar for anything that has to generate heat, LPG is much better but of course not free. Also an oven is really bad because it's typically on for hours.
Solar HW is a very different animal and (apart from the booster) nothing to do with a solar power system. So yes they are seperate but if you use the booster that will need to be powered from the solar. However see my comment about things that generate heat. Personally I would disconnect the booster but I live in a hot climate.
I'm pretty sure you could do this if you get a sparky to install a changeover switch, I dunno if there are any rules regarding this though. A simpler method IMO is to forget selling power as that benefit gets less and less every year, just use the power to charge the batteries if required.
Good DC fridges are still better than 240v domestic fridges, but the difference is less than it used to be, DC fridges cost about 3x their domestic equivalent, and solar panels are really cheap these days. So people are starting to just add a few panels and saving $1500 on the cost of a DC fridge.
You can get 12v microwaves but they cost a fortune as well and there's very little choice of brands. If that's the only high-power device you have I would say it doesn't make sense to size the system around using that for 3 minutes a day. As you have to have a gennie anyway fire that up to run the microwave. If you want to run the microwave off the solar (and I do) you have to size the system to handle at least 100A from the batteries (at 12v), this means BIG and short wires and ideally) a lot of batteries because pulling that from 1 or 2 will give them a hernia. And also you don't really want to use that much power at night when it can't be replenished, which is exactly when you normally use a microwave.
Also remember that a microwave's rating is the heat it puts into the food, not the power it uses. A 600W microwave can draw a 1000W or more, that's about 80 amps @ 12v. Tip: using 24v or even 48v solves many of the issues regarding high currents, but from what you've said I think if you drop the ovens etc 12v would be just fine.
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hago
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Post by hago on Jul 27, 2014 15:17:04 GMT 10
you could all try my simple easy and free refrigeration technique if your serious.basically turn it off and throw it out the back.I,m not being cheeky.that,s what I did as a ......well it was a self hardening lesson at the time and then a monetary issue then just stubbornness and now I don,t even realize its not there. We have extraordinarily little wastage. My whole concept of prepping is to do it as cheap and tough as possible so that when it becomes reality its less of a issue on the senses amongst the other hundreds of things that'll be happennig.where going on 4 months now. The last prepp site I visited shot me down left right and center which I felt spoke volumes on their personal idea of prepping.It was definatley a challenge and my tummy expanded slightly because of it and I,m sure my blood pressure went up to but in a short time I was back to my usual healthy options.these and a lot of other things we think we need we don't.Not really.I will be getting a fridge n
back for summer as I feel I made my point to myself but I,m thinking maybe I should go through to the exact 1 year mark to see.OH sorry if this is the wrong place to post this ...topic I,m really into solar these days hence why it,s ended up here.
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Post by You Must Enter A Name on Jul 27, 2014 15:28:51 GMT 10
it's all relevant mate, someone else did a thread on the lack of a need for a fridge 12months a year, interesting read actually.
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hago
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Post by hago on Jul 27, 2014 15:41:24 GMT 10
the only thing that sucks huge electricity that I might miss is the clothes washer.apart from that.....I don't watch t.v at all(do watch dvds)but refuse to watch televised programs plus don't have a hd tele anyrate so that's that out of the way.I really think once my kids are old enough and capable I,ll probably just throw on my kit and that,ll be the last of me for a while.maybe some guerrilla recons into.....walmart.?ha ha.Its sorta like the lottery your in it and it,s possible but every week I get disappointed when I don,t see a zombie running down the street.I know its silly but that's gotta be my favourite scenario.floods and earthquakes are realistic but boring.plus there will be no coms or phones or ipods,pads air or whatever they called so we will need recreation and day to day survival will need to be punctuated with something....okay I,m way off thread,just thinking out loud.well better get back to study so I can be a good sheeple.
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