|
| Author |
Message |
WY_mark
Member
|
# Posted: 28 Mar 2013 11:00am
Reply
Hi everyone,
I'm three books and a ton of forum articles in and I feel more confused than when I started at ground zero. Seems like I keep getting books that want to teach me math and chemistry and not a basic, buy this, put it here instruction guide. Online it looks like most are trying to DIY something for under a grand that maybe safe maybe not. (no offense meant to anyone going this route).
Our cottage should run nicely on a 3000watt off-grid system from all I can tell. we could probably even be pretty happy with 2000watts. we have exceptional solar access and I'm a competent handyman. I've rewired our entire house (to code, with permits) and am confident in non-solar electric projects. Quotes I've gotten for system installation run in the $16,000 range and that seems like a ton. Online I see systems in the $6-8k range but I've not got a clue how to judge them.
I'd love to get out of this for $6k or so, but I'm just not sure where to turn or what to get. at this point I'd really just like a heap of materials and a sheet of instructions that says where to put things. Where would you turn? Are there whole systems or online retailers that you like trust for this scale of thing? is there a service you like that will take your situation and design a shopping list?
many thanks for any ideas.
Mark
|
|
VTweekender
Member
|
# Posted: 28 Mar 2013 12:42pm
Reply
If you want people who provide the best service as to what your looking for and trustworthy then buy from the guys at backwoodssolar.com. And they will help you every step of the way.
|
|
Truecabin
Member
|
# Posted: 28 Mar 2013 01:33pm
Reply
When you buy a complete system they are always bigger and more robust than you would have assembled on your own. Sometimes it seems like it's better to get the robust system in the first round rather than saving money and wishing you would have bought it later. But in the beginning there are budgetary constraints that drive the decision and after that it's all hindsight that can't remember the original concerns. Putting a $2000 system out in the woods for some crackhead to steal is less risky than a $6000 system "out there". 3000 watts will run a "small house". What do you need all that power for, washing machines, dishwashers? You could buy a $1000 system and get going, learn a lot, learn how much power you need, perhaps adjust/reduce your 'needs' then sell it quickly for $500 loss. You could pay someone $4000 to take it away and and lose less than overbuying a $16,000 system not knowing your needs. Internet wisdom almost always goads you into overbuying, be careful with that. Craigslist has all kinds of great values because people overbuy to impress others on the internet and this waste flows onto craigslist.
|
|
WY_mark
Member
|
# Posted: 28 Mar 2013 01:51pm
Reply
my 2000-3000 watt estimates are based on our desire to basically have a small house instead of a very rustic cabin. we've built a 600sf tiny house that I'd like to have a fridge in basically fulltime since we'll go every weekend. I'd like ceiling fans and hopefully an evaporative cooler as our climate is absolutely perfect for them. a small microwave would be perfect. otherwise our power needs are minimal now, but who knows what we'll grow into (or decide we never need).
I guess I'm not so worried about theft of a $6000 system. anything more than that is just more money than I have. we have great neighbors and are in the middle of nowhere, random traffic is pretty much non-existent. our pile of building materials sat unsecured for 3 months during construction without a single loss. we had one freak windstorm that blew the rocks and tarp off our osb and scattered 11 sheets across our property. some incredibly nice soul gathered it all up, restacked and re-covered it and put 3x the rocks on it. no one will tell me who so we can buy them a beer or bake them some cookies. it's just the way people are around us.
I'd love any suggestions on even a 1000watt "learning" system. one thing I gather is that there are a lot of people doing just fine with lower grade charge controllers or missing safety switches. I just don't think I'm willing to take the chance with my family. I know it could run forever and never catch fire, but I can't bring myself to skimp on things that are ultimately questionable in safety.
one question on a smaller system. I'm planning on installing a 100amp box and wiring the house as I would a grid tied house. Assuming I don't draw more power than a system of any given size can produce, is there any reason a smaller system wouldn't work tied into this?
|
|
ICC
Member
|
# Posted: 28 Mar 2013 03:47pm
Reply
The hardest part of designing your own system, or buying a package is making the accurate estimation of what the actual power use will be. Many people underestimate. When looking at a commercially available package solution, I feel most vendors, if not all, will err on the side of more capacity than needed. That's because if the system is too small that will be quickly become apparent. Too big gives a cushion. Many DIY people make the error in the other direction. Many DIY systems that fail to perform fail because of too small of a PV array and/or because of insufficient storage capacity. Increasing the size later has problems too.
On the safety side I believe it is foolish for anyone to skimp on the correct fuses, disconnects or any other electrical equipment.
I am always leery of electric refrigerators operating on small PV systems. I know from experience that we would need to have nothing less than 5 days of storage capacity to ensure the fridge lept running when we were away. I could play the odds but I'm not that kind of person. So we use a propane refrigerator. An alternative would be to have a system with an autostart generator, fueled by propane, to come on if and when the batteries were discharged to a preset point.
It sounds like the 100 amp panel should be fine no matter what you feed it with. It's what you pull out that is important to your satisfaction.
I don't like re-doing things, especially if that means buying new equipment to replace something that was undersized or of poor quality. I'd be careful and conservative with the estimate on the power use. If you do that well there are systems available from many sources that will do the job. You do pay the vendor something for that.
|
|
WY_mark
Member
|
# Posted: 28 Mar 2013 04:47pm
Reply
ICC, I've considered propane fridges too, how much do you find you use just to keep the fridge running while away?
thanks for the suggestion of backwoodssolar - super friendly and helpful!
|
|
ICC
Member
|
# Posted: 28 Mar 2013 05:22pm
Reply
Our fridge is a Servel 400. It's rated at 1.1 lbs pf propane a day at an ambient temp of 77 F. We are in a basically cool location and the cabin stays below that because it's insulated well, and use less than a pound a day, maybe 45 - 50 days on 40 pounds.
|
|
Truecabin
Member
|
# Posted: 29 Mar 2013 06:38pm
Reply
Reading/learning here. Thanks ICC for your technical descriptiond. I had to actually buy some stuff and start to get the focus I needed (to learn it). It's taken be a couple years to get comfortable with the subject, and I'm still just starting, but the sooner you start the sooner you learn.
Relevant to this discussion I had a recent conversation with some folks who have been off-grid for 25 years. Their solar panels were sized OK but as time went on, the trees got bigger, reducing sunlight to their panels. At some point they realized that watching meters and dials did not entertain them like it did in the old days because depending on what the dials and meters said someone was going to have to go to town, buy, carry & pour gasoline. This came to a head and they added a 20A micro-hydro system in addition to the solar and are happy with it. 20A is a lot when you think of 24/7, power to burn sort of. I'd heat the floor under my kitchen table if I had hydro. They are currently fussing with a little shack to restore quiet though, but prefer the new whine over the old generator. At this point they seem thankful for the extra power, and maybe getting older, can't hear anyway . Point being there's something to be said for buying big if you have the $$. I would buy big on solar though, it's quiet and no moving parts to wear out plus few people can poach a stream.
|
|
|
WY_mark
Member
|
# Posted: 29 Mar 2013 11:29pm
Reply
oh to have a stream within a mile of my property ;)
I've been disappointed that wind doesn't look like a great idea. we have a nearly constant breeze and substantial windy days (today was about 18mph all day) BUT I'm at the base of a bluff and we have a turbulent choppy mess of wind.
|
|
Moving Pictures
Member
|
# Posted: 31 Mar 2013 07:48pm
Reply
Try looking at ways to reduce your consumption if you're thinking solar
- LED lights instead of incandescent
- DC fridge such as a Steca or Sundanzer
- Avoid high-energy appliances (coffeemakers, toaster, ovens)
$16,000 is basically 2.5 times what I plan to spend to build an off-grid home....
|
|
TheWildMan
Member
|
# Posted: 2 Apr 2013 09:14am
Reply
if your not interested in the math aspects you should not look into solar. had to learn solar as i went (lived without any power for 6 months before i got my first 30 watt pannel and a single battery. you need to be able to manage the power supply. i remember asking about electronics and asking how much wattage or amps they needed to run onand most people look at me in confusion and respond "whatever comes from the wall (outlet)" if your used to plugging into the wall and running whatever whenever it will be a huge change when you need to budget your wattage and not the power bill. to avoid problems with cloudy weather and energy hogging electronics you would need a massive system and would be better off (and probably happier) on the grid. if you can't do some of the math then solar probably won't benefit you.
i offer this advice from experience, i knew people who jumped in and spent huge amounts of money to make up the difference in not knowing how to run their system, in the end they would have spent less if they stayed on the grid, don't want you repeating their mistakes.
|
|
Truecabin
Member
|
# Posted: 2 Apr 2013 11:29am
Reply
Like everything, levels of economy can be had by doing some of the work yourself. Real economy is when you don't have to do the work, and the cost doesn't land on someone elses shoulders. Even better if you enjoy the work. Work can be good for you, it keeps you able and clears your mind. Math is good too, don't try to avoid simple math - that won't do you any good to let your mind rot. To pay for utilities requires money that you were taxed to obtain, so the cost of buying utilities can be more than comparing the face value.
|
|
WY_mark
Member
|
# Posted: 2 Apr 2013 12:51pm
Reply
for anyone that cares, looks like backwoods solar will be a fabulous option for about $6800 on a complete system that should let us exist quite comfortably. could probably knock a solid $600 of shipping off that sourcing locally but they've spent hours with me on the phone and email and I don't feel it's fair to mine their experience and then buy somewhere else.
|
|
creeky
Member
|
# Posted: 2 Apr 2013 01:47pm
Reply
WY_mark
I built my own offgrid system two years ago for around 6k. I went to look at the backwoods systems and I'm speculating that their site hasn't been updated in awhile. the solar panel sizing is just way too small.
I have 1000 watts solar 48v (1800 then about 1200 now) going into a Morningstar 60 amp mppt controller (600). That runs to 1200 amp hrs batteries (1800) at 12v. Wish I'd gone 800@24. But c'est la vie. It is still a remarkably robust system. I have a 3000 watt pure sine inverter (Ramsond) was 600 but now I think they're around 800.
Add a combiner box, wiring, mounting hardware, a small well insulated 8x8 "solar shed" I built myself and you're at the 6k mark.
With experience I've added a 75 amp charger (200) and I already had a generator (1000). I use this equipment only in the late fall/early winter when we are very cloudy here.
My system runs a large screen tv, kettle, blender, lights, high speed internet etc with ease. I was in a trailer (RV style) but it ate a lot of power with hidden loads... esp. the "power center."
I am adding 500 watts of solar for the fall/early winter to reduce the use of the genny/charger. It will also allow me to run a small airconditioner on those hot sunny summer days without hitting the batteries. I'll probably add another controller as well.
My system generates over 3kw per day. 6 kw is my record. Currently (since moving into the "studio" and out of the RV) I'm using about 2kw/day. With spring daylight hours I am "on float" ie. fully charged 14 days in a row now.
My suggestion for a small cabin if you have lots of sun: At least 1 kw panels. A good mppt controller (there's an 80 amp out there). A pure sine inverter. And I'd go 24/48v with 800/400 amp hrs if I wanted a fridge.
I've used a propane fridge for the last two years and it gets tired paying money to fill tanks and drive for an hour. 2014 will see new energy use rules for fridges, so ... can you wait a year on the fridge?
Good luck.
|
|
WY_mark
Member
|
# Posted: 2 Apr 2013 02:26pm
Reply
we can wait longer on the fridge. I have a not bad not great "dorm" fridge that we can plug in while there and turn off when not there. really my challenge right now is that I want to get the wires in the walls so I can spray foam insulate.
I'd love to see your setup if you've got photos. the $6800 mark is from their written quote, not their web site. either way, they've been very nice which counts for a lot these days.
|
|
VTweekender
Member
|
# Posted: 2 Apr 2013 03:34pm
Reply
Quoting: WY_mark for anyone that cares, looks like backwoods solar will be a fabulous option for about $6800 on a complete system that should let us exist quite comfortably. could probably knock a solid $600 of shipping off that sourcing locally but they've spent hours with me on the phone and email and I don't feel it's fair to mine their experience and then buy somewhere else.
Excellent choice, they will be there when you need them!
|
|
Truecabin
Member
|
# Posted: 2 Apr 2013 04:20pm - Edited by: Truecabin
Reply
Quoting: WY_mark I have a not bad not great "dorm" fridge
Don't think of a dorm fridges as saving power. Look at the energy star rating. There are modern "apartment size" fridges (with freezers) now that use less energy than a tiny dorm fridge. Dorm fridges are made to be be attractive to people who could not care less about the power usage (cuz they don't pay) but want the lowest purchase price. They all use power-hungry components, I looked quite a bit and never found one that wasn't a total hog.
|
|
WY_mark
Member
|
# Posted: 2 Apr 2013 04:28pm
Reply
yeah I'm not thinking of the thing as a end run, but it'll work a bit until 2014 models hit. ours isn't bad, has an actual freezer, doesn't suck a ton of power.
|
|
creeky
Member
|
# Posted: 9 Apr 2013 09:31am
Reply
i was looking at some "camping" 12 volt fridges last weekend. 13 amp draw! that's a lot of power. not sure how often they run though.
Also looked at an "apartment" fridge. 515 kw/hr. I was really disappointed. A good regular fridge is 400.
I've seen some great posts on insulating your fridge. You might want to look into that. The technique seems to be: route the hot air from the compressor away from the fridge; add lots of insulation to the sides, top etc; block air from spilling out when the door is open with a plastic sheet...
|
|
|
