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charliebishop
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# Posted: 15 Mar 2013 08:47
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Hi all!
Long time lurker, first time poster 
I have an acre of land tucked away deep in the woods on the avalon peninsula in Newfoundland, Canada (beautiful area if you've never been! amazing trail networks along the coastline).
My wife and I plan to build a larger cabin in a few years time, but for now I've built a 10x16 barn style shed (picture attached) that we are using as a quasi-cabin for the time being. About to start construction on a greenhouse as soon as our snow melts!
So we were originally planning on waiting till we build our larger cabin before investing into our renewable energy system.. However just the other day our local Canadian Tire had a sale on its solar panels, so I bought 3 40watt panels (picture attached) for just under 250 dollars.. I thought it was a good deal!
I have a few questions about setting up my system. A little on my background: I have a bachelors degree in physics, and a masters degree in environmental science - I work as an oceanographer full time so I do have quite a bit of a science background
I understand the system works like so: Panels -> charge controller -> batteries -> inverter -> appliances.
My question is: can I get a charge controller and an inverter that are able to be hooked up to a computer so that I can record how much power I am generating, and how much my appliances are using? (I'm more interested in the generation side of things.)
Or perhaps there is a datalogger product out there, that I can wire into the renewable system that can plus into the serial or usb of a PC? I'm looking for something that doesnt require much work (nothing homemade!
Also, I'm having trouble figuring out what size of battery I should buy for these 3 panels - Calculating how much energy they will produce is proving challenging.... the photo attached shows my shed, and the roof is pointing east (the west side is right next to the trees as you can see). I understand that this is not ideal for solar, but we plan on building our larger cabin with a roof angled to the south to take advantage of more sunlight.
If anyone is interested, the computer I have purchased is a Fit-PC2i , it only uses 6watts! (http://www.fit-pc.com/web/fit-pc/fit-pc2i-specifications/)
I will also soon be setting up a Davis Vantage Pro to monitor the meteorological conditions down there.. I plan to record the wind speed for a year and then add a wind turbine to this system (which will undoubtedly overpower the solar aspect, as we have one of the greatest areas for wind power) ... so for the data logger I'm looking for, it would be great if it could also record the output from a turbine as well.
Can anyone send me some recommendations? 
our_shed.JPG
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solarpanel.JPG
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Just
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# Posted: 15 Mar 2013 10:40 - Edited by: Just
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Very nice cabin Charlie ,I might add two things to your list of parts ,
A voltage meter ,so you know how much power you have in reserve and fuse panels for both your 12 volt and 120 wiring . I have not herd of a production meter for a 12 volt system .all I have is a 120 volt usage meter from CTC .
as far as mounting the panels, is there not room to mount them on the south wall above the barn door .they will produce lots more power .
batteries,, the only way to know how many you will need is to know your average usage per day x your average length of stay..
With 120 watts of panel you would not want more than 4 or less than 2 batteries
6 volt golf cart batteries are the best . hold about 100 anp hours each of which 50 amp hrs are available for use .
soooo if there were 4 batteries you would have about 2000 watts of available power= a 100 watt light bulb would burn for 20 hours before the batteries were considered low . a 9 watt cfl or a 2watt led will run much longer ..
your panels will produce 120 watts x 7 hours of sunlight average =840 watts per day ,,,,,,,,,,,,,,, you do the math then you will know
its all about using less not producing more.
I have 55 watts of panel from CTC 2 12 volt marine batteries from w mart. been running 6 years . there are lots of fokes here that know more than I but thats the basics .
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Anonymous
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# Posted: 15 Mar 2013 10:48
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midnight solar & outback charge controllers can be connected to computers, the midnight to the internet, they are upscale i also think the upscale xantrex can be used with computers but never used them
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bobbotron
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# Posted: 15 Mar 2013 10:54
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If you're tech savvy, you could get an arduino, and build your own monitor!
That fit-PC is cool - where'd you buy one in Canada?
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CabinBuilder
Admin
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# Posted: 15 Mar 2013 11:48
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Quoting: charliebishop I'm having trouble figuring out what size of battery I should buy for these 3 panels - Calculating how much energy they will produce is proving challenging....
Search this forum - you will find several threads in this subject.
For example, Solar Size Up.
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Moving Pictures
Member
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# Posted: 15 Mar 2013 18:57
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The panels you have are designed only for 12v charging. Assuming you have a cheap controller (pulse-width modified) you'll only be, at best, using about 66 per cent of the available power. Secondly, you will only generate maximum power for about three hours a day - and that depends on your insolation (sun hours per day.)
I will be blunt: The above poster, stating 840 watts per day is, frankly, grossly inaccurate and clearly hasn't a clue what he is talking about. Or, to put things in perspective, on a reasonably bright sunny day two days back, my pair of 240 watt panels - 480 watts - connected to a high-efficiency MPPT controller, generated about 1.2 kw of power. The above poster would have you believe that 1/4 of that power total (120 watts) with a lesser controller, will somehow obtain 840 watts. It won't. (Even assuming full efficiency, seven hours per day, you'll get maybe 80 watts an hour through a PWM controller, so even assuming full sunlight - which isn't gonna happen - you're looking at 560 watts per day.) A better guesstimate would be maybe 350-400, on a good day.
Batteries. Again, the above poster gave you bad intel. A battery should only be discharged to a MAXIMUM of 50 per cent of its rated total. So if you have a 12-volt, 100 amp-hour battery (1,200 watt-hours total), the maximum drain you should take out of it is 600 watt-hours. Ideally, you'd want to only take down to 75 per cent or so, meaning that a 100 amp-hour system, that's about 300 watt hours.
As many people in the Pacific Northwest can tell you, it ain't sunny all the time. That's why a good solar system will plan on being unable to charge due to weather for at least three, and ideally five days. Let's take three days. That means, if you're using a 100-amp-hour battery, that you should only plan on pulling 100 watt-hours a day out of your system.
Your computer chews up a mere six watts? Impressive. But that's still 144 watt-hours per day. Or, in other words, your computer is going to consume more power than your panels, in average conditions, can be relied upon to provide.
The best batteries are purpose-built deep cycle batteries. They are heavy and expensive. However, for $2,000, you can obtain a superb solar system - with a pair of purpose-built 230-ish watt panels, an MPPT controller, and something on the order of a pair of 6v, 350-380 amp-hour batteries. That will give you the power to draw a decent load of about 300 watt-hours per day, without sacrificing your batteries. ON sunny days, you could do more.
But again, put things into perspective: a coffeemaker, if you run it off an inverter, is going to pull a good kilowatt for about six minutes. That may not sound like a lot, but that's 166 watt-hours, right there, and that's assuming no losses - which there are. In fact, losses in the inverter will likely mean a 200 watt-hour draw at the batteries.
Please, do some research. And if you can return those panels, do.
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Just
Member
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# Posted: 15 Mar 2013 19:35
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Like i said others know more than me. I do know however I am vary happy with my little system and if you are carefull about what you use you will be very happy with your starter system also .. good luck..
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Anonymous
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# Posted: 15 Mar 2013 21:59
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The OP faces sort of a unique situation. newfoundland has almost no good solar power producing sunshine in winter and not that much in summer compared to most of canada and the usa. hope the winds really are dependable but not so strong to blow the equipment away. [url=http://pv.nrcan.gc.ca/pvmapper.php?MapSize=500%2C500&ViewRegion=Quick+Zoom&CMD=Z OOM_IN&minx=-2508487.000000&miny=5139927.500000&maxx=3080843.000000&maxy=10729257.500 000&imagewidth=500&imageheight=500&CHKBOX[4240]=4240&CHKBOX[2057]=2057&CHKBOX[92105]= 92105&units=0&tilt=1&period=7&title=PV+potential+and+insolation&title_e=PV+potential+ and+insolation&title_f=Potentiel+photovolta%C3%AFque+et+ensoleillement&lang=e&LAYERS= 2057%2C4240&SETS=1707%2C1708%2C1709%2C1710%2C1122&RLAYER=92105]here are insulation maps [/url]
It.s been covered elsewhere before but the place to start is to estimate accurately the use, then add 20% for good measure. start with sizing the battery capacity. return the Canadian Tire panels, they are not the source for high quality PV parts. . don't buy anything till you figure out what you need. no out of the blue, its on sale today, i think i'll snap it up, buying. expensive mistakes are made that way.
when the battery capacity is known then figure out how much solar and how much wind is needed. each needs a separate controller. as far north as you are a generator may unfortunately be indispensible, if it has electric start so it can auto start so much the better.
if this is a part time place think about how the batteries will be maintained fully charged when you are away. a good system can run iyself for months untouched by human hand.
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Anonymous
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# Posted: 15 Mar 2013 22:14
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that link sucked maybe start here and click on the maps link. looks like in Jan you might have 2 - 2.3 kWh/m2 per day. not too much. if there was ever a place where a panel tracker would be a real boost this is it. more info
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Anonymous
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# Posted: 16 Mar 2013 11:42
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In my opinion a "Panel tracker" (that moves the panels to follow the sun across the sky) is be a costly PITA and it would break someday soon. With the lower price of panels it would cost much less to buy another panel and set one easterly and the other westerly and last 25 years, and give you more in the mid-day.
Sorry charlie on the canadian tire stuff. There are considerably better kits available. You will most likely need more than 120W because of the non-sunny days, you can't add to that system, you're tapped out, maxed. You can get a 200W panel for about $200, and a 30A charge controller for $30 which will put you at about the bottom of what your started kit should be, for less. With a 30A charge controller you can add another panel later if you start to use more power add batteries, (or experience less sun like always happens in the north).
Keep reading up and you'll find better prices. What you want is very doable. Maybe you learn with what you got and sell the canadian tire stuff when it's time for a bigger system.
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Anonymous
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# Posted: 16 Mar 2013 11:44
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oops need a 40A controller if you want to start at 200W panel and and 2nd 200 later.
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lumpkin
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# Posted: 16 Mar 2013 22:54
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Fergit the inverter - too much loss. DC to DC, 24V is your friend. No 110AC.
Datalogger -
http://www.dataq.com/products/hardware/easylog-data-logger.html
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Dillio187
Member
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# Posted: 17 Mar 2013 01:15 - Edited by: Dillio187
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I disagree. look at the morningstar suresine 300. less than 55ma at idle. awesome inverter.
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charliebishop
Member
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# Posted: 20 Mar 2013 08:56 - Edited by: charliebishop
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Hi everyone.
Just wanted to say thank you for the advice!
I feel like maybe I misrepresented myself and didn't portray what I'm trying to do.
As of right now, we only go into this land maybe once a month, just for the day... there are no electronics besides this small computer... Though I may add 1 CFL bulb and an outdoor light (still deciding on that).
I'm not trying to set up a power system here, I'm thinking of it more as an experiment to see how well the solar would perform (Newfoundland in general is very poor for solar radiation).
It will be several years before we build our large cabin, at which point I will design a completely new system based off the knowledge I get from playing with these crappy Canadian Tire panels. By the way, Canadian Tire seems to be the only retailer that sells PV panels here, which is why I bought them - I could return them if someone could show me a link online where I could buy the same amount of wattage (including shipping/duty/taxes)... but seeing as how its just to play with, I think it will be ok for now.
Moving Pictures:
I appreciate your advice, I can tell you know what you're talking about. On the wattage of the computer, I don't need to run it 24/7. I have a "wakeup" utility for this machine so that it can wakeup every 2 hours, for 15 minutes (download from the dataloggers, send the data to my ftp by wireless and then go back to standby mode) .. in standby mode the machine only draws 1.5 watts. At this calculation, I'm estimating my daily watt-hours to be ~50. About a third of the power of running it 24/7. I can play with my wakeup times, if need by I could only wake it up every 4 hours, or 6 hours, etc. (Right now I choose 2 hours as I'd like to see the data updated to my webpage fairly regularly but am flexible on this).
I know generally one would calculate what devices will be powered, then size the batteries and panels accordingly.. but seeing as how I have no other devices, and this is just to play and learn with.. How do I do the opposite? Essentially what I'm asking, is I have 3x40watt panels, what size battery should I buy such that it will remain charged? (I can then adjust my computer wakeup times so that it never uses more than 50% of the battery amp hours, even if this means I turn it on 1 time every X days)
Please keep in mind, all I am trying to accomplish is getting data from my weather station without actually driving down there every day and downloading it myself, thats my number 1 goal my second goal would be logging the data from the solar panels themselves, ideally through the winter, so that I know an average of exactly how bad solar really is here
if someone could provide me some links to some mppt charge controllers that plug into the USB/serial of a computer, I would really appreciate it.. logging my data on these panels would really help me get a grasp on how much power they do indeed generate. Anything out there less than $500? It doesnt actually need to be part of the charge controller itself i guess, any turn-key product that I can connect to my system that logs data would be acceptable.
When the time comes to build my cabin I will be buying all new components (except maybe the charge controller that I can currently looking for), can someone suggest a canadian retailer that has affordable solar panels and batteries? Though I do believe we will be going with more wind power than solar, I would like to be a hybrid system.
Thanks again!
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Just
Member
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# Posted: 20 Mar 2013 09:36 - Edited by: Just
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Go to your nearest golf course and ask were they get their 6 volt deep cell batteries, they will know were and how much , sounds like 2 batteries will do you for the next few years but depending on sunlight you may want four . should be about $ 120 each .. here in Ontario Cosco stores have the best price.At one time CTC. did sell a large 12 volt deep cell solar battery $250 [ not sure if they still have it ] . I have a friend that has 4 of their batteries and one of their small wind mills.I have no idea about the controler you are looking for. C.T.C. has a 6 volt deep cell golf cart battery on line .Good luck
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