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spencerin
Member
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# Posted: 29 Jan 2013 22:25 - Edited by: spencerin
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This is for the beginners. After reading so many solar posts, I wanted to post my self-designed, self-installed 12V solar power setup. I'm dang proud of it and it works!
The items are -
Grape Solar 100W Solar Panel ($212.93)
Home Depot
2 BPS 50' Solar Cables ($99.06)
Amazon.com
10-Amp Sunforce Charge Controller ($34.04)
Amazon.com
Cobra 1500W Inverter ($104.57)
Amazon.com
Cobra Inverter Cable Kit ($26.70)
Amazon.com
~4' Copper Grounding Rod ($13.99)
Amazon.com
3 Everstart 27DC Marine Batteries ($233.26)
Walmart
Misc Expenses (~$100)
(galvanized steel pipe for frame, conduit, and misc electric hardware, etc., from Home Depot)
~$825.00 TOTAL
You could probably get the total cost down to ~$750 with 2 batteries – I don't know that 3 were needed.
Appliances powered -
3-way floor lamp
29" flat screen tv
DVD player
1.2 cu.ft. refrigerator
700W microwave
1140W vacuum cleaner
radio
fan
I don't usually have any power draw issues except for the vacuum cleaner on occasion, which is a Cobra inverter limitation - only the floor lamp can be on during vacuuming. So, perhaps getting a better inverter is warranted. But, basically all other combos of appliances can be run simultaneously.
This is only for weekend usage, but the batteries have always been 100% charged upon arrival, even in the winter.
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Toofewweekends
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# Posted: 30 Jan 2013 02:10
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Similar set up for the last 2+ years. Less TV and smaller inverter, more CFL lights. Except in the middle of our Alaska winter with no sunlight, the solar setup you described works fine for weekending.
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aktundra
Member
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# Posted: 30 Jan 2013 16:08
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spencerin
Hey thanks for posting this! I have been working on designing a system, but the more I try to learn/research, the more complicated and expensive the system seems to get.
What brand fridge are you using?
Any pictures of the system?
Toofewweekends
Mind posting more details on your solar setup? I'm up in Alaska too and really only need solar for basic charging, lights, 12v pump. So are your lights AC?
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hitanktank
Member
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# Posted: 30 Jan 2013 19:15
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great post thanks for ideas
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Borrego
Member
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# Posted: 30 Jan 2013 21:37
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Thanks!
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spencerin
Member
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# Posted: 31 Jan 2013 00:06
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Quoting: aktundra What brand fridge are you using? Any pictures of the system?
Actually, I don't know what brand fridge I am using, lol. I bought it off Craigslist.com. It's one of those cube-sized ones, the smallest you can buy. My inverter shows it draws 100W when running (cooling), which is why I got it (I asked the guy ahead of time what the amp draw was). The amp/watt draw was a little less than a new Haier you can buy in the stores (they draw ~120W), but it works just fine, so I saved a little money and a little amp draw on the batteries. Honestly, in retrospect, I probably could have bought one of those ~3' fridges, but this was my first foray into solar power and space is also limited, so I went with the cube.
I'll have to take some pics of the system - some items I have pics of, others I don't. It'll be a couple of weeks before I can get them posted because I don't plan on getting out that way this weekend.
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phlather
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# Posted: 31 Jan 2013 11:28
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This is exactly what I needed to read. I am a super rookie when it comes to solar. I will sign up here now, and start learning. Thanks.
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skootamattaschmidty
Member
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# Posted: 31 Jan 2013 19:08
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Thanks for the post! I am just debating what I wneed as well and that sounds perfect!
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Moving Pictures
Member
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# Posted: 31 Jan 2013 19:25
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Your batteries can't appropriately source the load you are putting on it, including the vacuum cleaner.
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Just
Member
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# Posted: 1 Feb 2013 18:05
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Must be my week for improvements ,Just added 40 more watts of panel to our system.I can't beleave the size compaired to my 6 year old blue planet 15 watt panel . 2\3 the size and almost 3x the power. 99.99$ C.T.C. can. cash and carry in my home town'..
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spencerin
Member
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# Posted: 2 Feb 2013 23:53 - Edited by: spencerin
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Moving Pictures,
The setup's fine. The Cobra inverter was not the best 1,500W inverter that could be bought, in hindsight. The low voltage cut-off of the inverter is supposed to be around 10V, but no matter what, the "alarm" goes off when I run the vacuum, and although 95% of the time the inverter doesn't shut down, 5% of the time it does, so that 5% of the time I can't vacuum, yet, all the while the voltage meter shows in the lower 11Vs on both the inverter and charge controller, well above the 10V cut-off design. The vacuum is rated at 1,140W, well within the inverter's 1,500W design. The alarm also goes off continuously when I'm running the 700W microwave, though the inverter never shuts off. I just have to listen to the stupid thing until the microwave shuts off.
Not worth getting rid of a functioning inverter. It's not crap, but it's not the best. The Amazon buyer reviews confirm it.
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razmichael
Member
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# Posted: 3 Feb 2013 09:23
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Won't argue with you about the cobra inverter but you should be careful with your estimates on power. 700 watt microwave - this is the cooking power. Actual draw can be up to twice that (google it). Also using an inverter for a microwave can be tricky (especially a modified Sine Wave. Cooking ability will be very dependent on the input voltage. See Microwave . The inverter may also be alarming for one of the ohter error conditions.
Vacuum rating does not account for start up draw. Given inverter loss added to the mix, you are expecting a lot from a low end inverter. Add the fact that the batteries are not true deep cycle batteries it is not a surprise that you are having some issues. Obviously you can make it work with only weekend visits but you are pushing the limits of everything and will expect these issues, early battery failure etc.
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optimistic
Member
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# Posted: 3 Feb 2013 09:35
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Great info!
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Dillio187
Member
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# Posted: 3 Feb 2013 10:22
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a couple of 6V deep cycle golf cart batteries in series would work much better, and cost less at about $80ea at Sam's Club or Costco.
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razmichael
Member
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# Posted: 3 Feb 2013 11:07
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One other point I will make (not trying to be critical but could be useful) - I'm really surprised on the Cable kit and the recommendation for cable size in the manual. The manual for your inverter states:
"#4 AWG stranded copper cable is recommended.
It should be no longer than four feet (one and one-half
meters)."
The kit you indicated you purchased states it is 10' long. Looking at other sites I cannot find any inverter or site that would consider this even near to being acceptable. Most inverter manufacturers (at 1500 watts) would suggest a minimum of 2 gauge at less than 3' - at 10' length you would be considering 3/0 or bigger. Given the full loads you are using, with 10' cables at 4 gauge then you are will be suffering a lot of voltage loss even before you get to the inverter, not to mention a risk of over-heating and fire.
Being generous, that 700 watt microwave may be drawing over 100 amps from the battery at 12V (likely more - not sure on the actual draw of the Microwave and the inverter loss). This would mean somewhere around .5 volt DC drop before you even get to the inverter with 4 gauge cable at 10' length. I suspect this is higher if you knew the actual values and added in the other things running.
I appreciate that you followed the manual when purchasing the cable kit but this becomes another factor in explaining the limits of your system that you will need to consider when using it.
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spencerin
Member
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# Posted: 3 Feb 2013 12:18
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razmichael,
Again, the - system - is - fine. The - inverter - is - not - the - best.
1. You are correct about the cooking versus power wattages of a microwave. However, at double the cooking power (the upper limit), 2 * 700W cooking power is still within the inverter's 1,500W design.
2. I deferred to Cobra when determining what cable inverter kit to buy because I think they know their products best. The gauge of the wire is acceptable for the max loads because I verified this with Cobra before I purchased the kit. By the way, I cut the inverter cables to 3' before installing them anyway, so the run is not a problem. I also fused the cable within 3" of the battery in case of overloads with a properly gauged fuse - the fuse has not blown yet, even when running the vacuum for several minutes.
3. These are deep cycle batteries. No, they are not the best you can buy. Go to Everstart's website (www.championandeverstart.com) and you'll see the 27DC ("DC"=deep cycle) are designed for deep cycle applications. If I were a lot harder on these batteries, then, yes, I'd have purchased something better, but for my usage, they are perfectly fine.
Like I said, this system is a decent, rather powerful system for beginners and was designed to keep costs low as a result but still retain real functionality. The problems you cited aren't the problems - the inverter is the weakest link in the system.
This is actually starting to aggravate me because this is for the benefit of those who are venturing into solar power for the first time without much knowledge or money and not being marketed as the "best solar system ever". They will appreciate this because of its lower cost and real functionality. They don't need to be deterred by all these "potential" problems being cited that really aren't problems.
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skootamattaschmidty
Member
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# Posted: 3 Feb 2013 12:24
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For Just.
I just bought the same Coleman panel at CTC. Great deal especially when I used my Canadian Tire money to get it for free. How did you hook yous up to multiple panels? I only have the one but may buy another for 80 watts. Did you splice the wires from the two together or get a plug to join the too?
Thanks in advance!
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razmichael
Member
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# Posted: 3 Feb 2013 12:26
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Quoting: spencerin This is actually starting to aggravate me because this is for the benefit of those who are venturing into solar power for the first time without much knowledge or money and not being marketed as the "best solar system ever".
Not trying to aggravate you and I tried to make that clear. I am all for being able to build an inexpensive system that works but I also think anyone looking at it should fully understand the limitations and make sure they have proper expectations. You posted problems with the system (inverter) and I posted some potential factors. Your aim to help people without much knowledge or money is great - but adding some knowledge is not a bad thing. if it does not apply to your setup then I apologize - I was going by the initial information you provided.
i will argue that the batteries are a hybrid so, regardless of what the manufacturer states they are not designed for heavy duty deep cycle use - I will add however that this does not mean they will not do the job - they just have limitations.
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buckybuck
Member
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# Posted: 3 Feb 2013 13:08
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Anything less than a 1.21 Gigawatt flux capacitor powered by a Mr. Fusion is a compromise.
I like the discussion, but at the end of the day, if it works for you, it works for you. (We are talking about how to provide minimal power to a small weekend cabin, after all). As Voltaire said, "Le mieux est l'ennemi du bien." (The Perfect is the Enemy of the Good).
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Dillio187
Member
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# Posted: 3 Feb 2013 13:08 - Edited by: Dillio187
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that's why I posted about the batteries as well, because people spend their hard earned money on this stuff! It wasn't meant to irritate anybody, rather give a better "bang for the buck"
I have installed quite a few of these off grid systems, and own and maintain 2 of my own, one 940 watt with 24V bank at my home, and one 320 (soon to be 480W) with a 12V bank at my cabin. I've come to realize that with solar, you get what you pay for. I have 3 cheap inverters sitting under my work bench because they either a) blew up, or b) caused issues with my appliances. One of them is a Cobra too! It makes my radio unusable due to the interference. I now run a 300W true sine wave Morningstar at my cabin, and a 1500W true sine wave Samlex at home.
The same is true for batteries. The 6V golf cart batteries have much thicker plates and are designed for deep discharges and rapid re-charging. For $75-$90 US ea, they are hard to beat.
I'm just trying to save someone the extra expense and headache as I've wasted more money on this stuff than I care to admit.
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Rick004
Member
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# Posted: 3 Feb 2013 13:46
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Hi Dillio187 !! It sounds like You know your stuff !! I am building in the spring and would like to be off grid ! I am going propane with fridge , stove , tankless hot water heater , and woodstove for heat , but would like solar to run a few lights , very small flat screen tv , and the coffee maker in the morning . I am looking at 2 , 100 watt panels but wondering on what size charge controller and inverter and how many 6 volt cart batteries would be required ?
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spencerin
Member
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# Posted: 3 Feb 2013 14:20 - Edited by: spencerin
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Yes, batteries are probably the most expensive part of the system. The only comment I have about the golf cart batteries is that to build a 12V battery for a 12V system you need to buy 2 and wire in series - that's $150-$180 for what is essentially one 12V battery. Now, I don't know what the Ah rating is on that.
Also, golf cart batteries are better deep cycle batteries due to how they are actually applied. People drives golf carts all over the place and infrequently recharge them. So, they need to be able to handle very deep discharges and are designed accordingly. With a solar system, you have the solar panel recharging them on a fairly continuous basis through the solar panel, except of course overnight. If you design a system right, the batteries don't really experience *deep* discharges, hence why I think those 27DCs are just fine.
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Just
Member
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# Posted: 3 Feb 2013 16:48
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skootamattaschmidty
I just clipped the 2 red and 2 black clips together . seemed to work fine .Quoting: buckybuck (The Perfect is the Enemy of the Good).
or as I like to say life is about choises
spencerin
my system is about 1\2 of yours we use it about 1 day a week 55watt panel
7 amp controler
1000 watt inverter
2 wallmart batteries 280 amp hr.s.total
# 2 cables
I ALSO HAVE A 700 WATT MICROWAVE SEEMS TO WORK WELL 'there may be somthing wrong with that inverter ,only thing I can see .
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Borrego
Member
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# Posted: 3 Feb 2013 17:12
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Spencerin - thanks for the thread! question: do you have your cabin wired 'like a normal house' and run your inverter through a regular main panel?
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Borrego
Member
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# Posted: 3 Feb 2013 17:19
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Appliances I'll want to power are similar to use yours:
3-way floor lamp
29" flat screen tv, maybe 36"
DVD player
1140W vacuum cleaner
IPod player
2 ceiling fans w/ lights
6 LED can lights
bath light and exhaust fan
2 wall lights
Does this sound like a similar load to yours? (in your opinion, I understand)
Any pictures of your set-up??
thanks
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spencerin
Member
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# Posted: 3 Feb 2013 19:25 - Edited by: spencerin
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Borrego,
No, it's a very small cabin, so I just run everything from a power strip that is plugged into the inverter. That is a similar load, though I think you are wanting to run a few more items than I do.
It'll be a few weeks before I can get some pics up, but I'll do it just as soon as I can.
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hitanktank
Member
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# Posted: 3 Feb 2013 19:47
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I notice no laptops being run
I assume they can only be run through a pure sine wave inverter?
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Borrego
Member
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# Posted: 3 Feb 2013 23:09
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Quoting: spencerin That is a similar load, though I think you are wanting to run a few more items than I do.
I was figuring the lack of a refer and micro would balance out the few extra lights, lots less wattage, right? I'm getting really close to doing my first solar project so I'm bugging everyone on here to get it right.. (Or as close as possible and maybe expandable(?) )
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spencerin
Member
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# Posted: 3 Feb 2013 23:15 - Edited by: spencerin
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Borrego,
You're probably right. I was thinking about the number of items instead of their wattages.
Yes, I have read all over not to charge laptops on a modified sine wave inverter like the Cobra. I also read that any AC-to-DC adapter that is above 12V should not be run through a modified sine wave interver. My laptop adapter is 19V, so I won't test that theory. When I buy rechargeable power tools, like a drill, I make sure the tool's rated at 12V or below so as to avoid any potential "frying". So far so good.
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Borrego
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# Posted: 3 Feb 2013 23:21
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Quoting: spencerin Borrego, You're probably right. I was thinking about the number of items instead of their wattages.
So you think with a system like yours, maybe an extra panel & battery, I could run my current loads? Add on later if need be??? And since I've been reading about the inverter issue, what would you get if you had it to do again?
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