Author Topic: 100% off grid shed with Ebay stuff.  (Read 9621 times)

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Atokatim

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100% off grid shed with Ebay stuff.
« on: August 14, 2014, 09:17:55 PM »
I am looking to go the least expensive route to a solar system to have my shed 100% off grid.  My shed is a 16ft x 20ft fully insulated and sheet rocked.  I have a small AC window unit installed in it, a 240V air compressor (I can use grid power if needed on this), a computer that runs all the time, and 4ea 2 bulb shop lights (~60w each).  The AC runs all the time during the summer and I have a solar heater installed on the south side of the shed which breaks the chill.  A 110 scroll fan pushes air through the solar heater when the temp reaches ~150 degrees and shuts off at 110 degrees.  Total amperage draw I am guestimating is around 20 to 25 amps 110V while I am working in the shed.  I am hoping to piece together my own solar system to remove the shed from the grid, but am extremely limited on cash.  I am in the process of ordering solar panels from Ebay as inexpensive as I can.

Two things that I worry about are the charge controller and the inverter.  I don't need a grid tie inverter, but I need a reliable one that will not crap out on my in a year.  Ebay has quite the selection, but I have no experience with them.  I know... Ebay and reliable should not be in the same paragraph :)  The charge controller is something I may be able to build on my own with my knowledge of circuitry, but it may be cheaper to just buy an Ebay one.  Any feedback on this idea?

dnix71

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Re: 100% off grid shed with Ebay stuff.
« Reply #1 on: August 14, 2014, 09:30:23 PM »
Based on your numbers, that's not a shed. That's enough power to run a house without central a/c. You would need probably 5kw of panel to supply 1/2 that as power to take your shed off the grid, unless you just plan to spend 10 minutes a day in there and then leave.

I have 700 watts of panel and 4 batteries and it runs a 12v fridge, a 3 watt LED room light and a 12v fan.

Atokatim

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Re: 100% off grid shed with Ebay stuff.
« Reply #2 on: August 14, 2014, 09:56:10 PM »
I don't have a way to tell exactly how many amps the shed uses during the day.  I have a Smart meter on my house and can guestimate how much power my shed is using by a circuit I have build that detects the IR pulses from the top of the meter.  The circuit calculates the milliseconds between pulses and converts that into current watts being used.  My average while I am in the shed is around 1000 to 1100 watts including the usage of the house.  The baseline at night of my power usage is 500 Watts per hour to 600 watts per hour.  So I can guess that my shed uses an average of 500Wh to 600Wh while being used.  When the AC compressor kicks on, the usage goes up an additional 600 to 800 watts.  Since I can't pinpoint exactly what is turned on based on my program, I can't specifically determine what the shed uses.

I also have a circuit I built that turns the lights on and off based on movement.  If I enter the shed, the lights kick on and will stay on for 2 minutes unless it detect motion.  This circuit is run from a solar charged car battery.  It can last over a month with no solar input or additional charge.  That was my first step to turning it to be more efficient.

Attached is a screenshot of my program / online log of my power usage.  I have been monitoring my power usage for over a year.

XeonPony

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Re: 100% off grid shed with Ebay stuff.
« Reply #3 on: August 15, 2014, 12:39:29 PM »
proper inverter that is reliable 2k and up (No they will not be cheaper on ebay) at 3Kw and scalable

Proper charge controller that will do the job as advertised at the needed power level: 400 and up

Solar panels that will do the job as rated and last, 305w @ 270 dollars.

Stuff that will be use full in your system on ebay that will be cheaper? = 0
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Atokatim

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Re: 100% off grid shed with Ebay stuff.
« Reply #4 on: August 15, 2014, 02:48:36 PM »
Since I have to piece together this entire setup, I know it will be more expensive but if I can save up front money to last a year or 2, I can save the money I save from electricity and hobby money to upgrade to bigger and better parts.  I don't plan on running top of the line parts right now since I can not afford it. 

madlabs

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Re: 100% off grid shed with Ebay stuff.
« Reply #5 on: August 15, 2014, 03:06:35 PM »
Keep an eye out for older Trace models, like the 2512 or 2524. When they pop up they go pretty cheap and they are beasts! Just yesterday I pulled my 2512 because I upgraded to a 8800W, 48V system. It has run non stop since it was made and will be back up and running at my buddy's place in less than a week, to continue grinding it out.

Jonathan

Atokatim

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Re: 100% off grid shed with Ebay stuff.
« Reply #6 on: August 15, 2014, 11:49:16 PM »
Wow, those things go for $500+ on Ebay used!  I have converted a few battery backups for computers to run solely on battery power and still use the overload protection and low battery feature in them.  Cheap inverters :)   Not bad for free!  I have not figured out what their max load is yet.  I know I can run all my shop lights from one of them.

madlabs

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Re: 100% off grid shed with Ebay stuff.
« Reply #7 on: August 16, 2014, 10:23:29 AM »
Yeah, but they are good equipment. It also has a built in battery charger, something else you may need. Nothing else as good for the price, and I bet you can grab one a little cheaper than $500. It depends on if you need/want the system to run or if it is optional fun. If the former, I'd muscle up the cash. If the latter then gang up UPS systems!

Jonathan

Mary B

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Re: 100% off grid shed with Ebay stuff.
« Reply #8 on: August 16, 2014, 06:51:23 PM »
www.solarblvd.com can often have cheaper prices than eBay and you have someone to back up the warranty. There are other sources too that have reasonable prices that will often beat eBay.  Keep in mind that most of the 24 volt panels will ship truck freight and that is not cheap. Best to save and order 4 or more at once to offset shipping charges. I went with smaller 12 volt panels to make them easier for me to handle with a bad back and bad shoulders. Those can ship FedEx really reasonable. I went with these http://www.solarblvd.com/Solar-Panels-&-Systems-12-Volt-Solar-Panels/c1_269/p2711/Two-Solar-Cynergy-140-Watt-12-Volt-Solar-Panels-with-Y-Connector/product_info.html and have been happy so far, first set of 8 is going onto 2 years old now with no issues.

Atokatim

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Re: 100% off grid shed with Ebay stuff.
« Reply #9 on: August 25, 2014, 11:54:35 PM »
Can someone point me in the right direction for a decent charge controller that is around $100?  I would like it to be able to handle 30A minimum.  Amazon reviews are iffy and Ebay charge controllers scare me since it is an essential part of the entire system.

Frank S

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Re: 100% off grid shed with Ebay stuff.
« Reply #10 on: August 26, 2014, 01:03:56 AM »
This is what I have, admittedly there are probably better & more expensive charge controllers out there
 http://www.ebay.com/itm/LCD-PWM-60A-CM6024Z-Solar-Panel-Battery-Regulator-Charge-Controller-12-24V-1440W-/291223077946?pt=LH_DefaultDomain_0&hash=item43ce3f843a

 Actually I now have 2 of them in parallel bought from the same seller, to share the PV load but We used one for over a year logging well over 60 amps input many times. I was planning on adding more solar and didn't feel that the single controller could give me more production than it already was. I have 1200w of PV and the controller  is actually only rated for 750w @12v nominal 1500 @ 24v
 our 800 AH bank sees a 30 to 50 % discharge almost every night and has done so for 18 months now
 But do you research just because I feel I my controllers have been satisfactory being that they are JUST PWMs doesn't mean there aren't better ones out there I'd love to buy a pair of midnight classics one day and probably will when my system grows or I add wind to my system
  BTW I am 100% off grid so I depend entirely on my solar & diesel generator  Spring & fall we hardly ever use the generator when it gets really hot though the generator has to be run for several hrs per day for the air-conditioning in winter it is only run an hr of 2 every couple of days to make sure the bank gets topped off   
« Last Edit: August 26, 2014, 01:12:45 AM by Frank S »
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Atokatim

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Re: 100% off grid shed with Ebay stuff.
« Reply #11 on: August 26, 2014, 09:49:39 AM »
Thank you for the tip.  For some reason, I have been missing these on Ebay.  I have seen a few reviews with the ones with "round" buttons and was told they were better.  I just bought one this morning :)

Do you have your panels connected in series or parallel?  I am guessing the one you posted cannot handle the voltage for the panels in series.

Frank S

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Re: 100% off grid shed with Ebay stuff.
« Reply #12 on: August 26, 2014, 02:16:00 PM »
I have 8 panels 140w each there about all connected parallel.
  from each panel I have 4ft long 10 ga wires leading to a pair of  3/8" SS studs from there I ran #2ga wire 45ft to my charge controller/s also paralleled with #2ga to the main connection studs which are 1/2" stainless on these studs I have 4 pair of golf cart batteries tied to them with #000 cables 1 inverter has 500mcm cables 5ft long the other inverter has #0000 cables 5ft long my Shumacher 30/60 300 charger is hard wired to these studs as well  2 other things on the main studs are a a pair of 8ga wires for any additional 12 v I might add & a multi battery isolator ( Sure power industries 120amp model 1202) that connects my 4d battery for cranking the generator or the main engine

 Due to possible partial shading of one panel or another during the day I elected not to set up a system with a charge controller that would a PV set up in series with the high voltage.
 My thinking was with each panel directly connected to the lead cables there was less chance of damage to the panels especially with possible shading and this being such a small array there was not a huge advantage in watt hours.
 if & when I decide to double or triple my PV array & bank size  then I will step straight up to 48v     
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tanner0441

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Re: 100% off grid shed with Ebay stuff.
« Reply #13 on: August 26, 2014, 03:42:10 PM »
Hi

I bought a pure sine wave inverter from ebay, it was not expensive but it certainly wasn't the cheapest, rated at 800W continuous 1KW surge 240V. It ran for months without a hitch in my shed. Then one day the lights didn't come on when I flicked the switch. I removed the inverter and took it into the house, went for my evening meal, when I came back I connected it to a battery and switched it on. It worked perfectly, it worked for several weeks then stopped again.

To cut a very annoying story short, the gap between the PCB and the inverter case was so small that when the humidity went up and started to condense on cold surfaces the gap was so small that the condensation was transferring to the PCB, I then found only the under side of the PCB had any solder mask or coating, so the top side of the board was covered in condensation stopping the inverter from working.

I removed the board put it in the airing cupboard overnight and sprayed the complete board with conformal coating. To me it was an annoyance to anyone without the facilities I had it could have been a disaster requiring the replacement of the inverter.

I now read all the specs for any more items I buy including the humidity rating, something I never thought of doing in the UK in the past.

Brian

Frank S

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Re: 100% off grid shed with Ebay stuff.
« Reply #14 on: August 26, 2014, 06:13:57 PM »
Not sure just how Jermaine this post will be.
  But a few more things for consideration. location of the bank the charge controller the disconnects & the inverter are also very important.
 For disconnects to meet many fire department & city ordinances the array should have a disconnect outside of the structure along with warning signs for my Bus I have a simple 2awg quick disconnect the kind like you would find used on winches or jumper cables for service, emergency or off road vehicles
the bank should be located in a well ventilated(to the outside) compartment or closet
 no other electrical or electronic components should be in the same compartment with the bank,  all main battery disconnect/s should be located near the charge controller & the inverter/s
  that's just a couple of thoughts   
     
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Bruce S

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Re: 100% off grid shed with Ebay stuff.
« Reply #15 on: August 27, 2014, 04:51:52 PM »
Apologies to the OP for possibly taking this thread into a different direction.
What Frank S brought up is interesting , with due respect to FD and city ordinances.
Since I work at a FD HQ now, and we have SOPs in place, I'm wondering what other SOPs happen to look like.

Cheers
Bruce S
If this takes the thread too far off kilter , I'll split it off to a separate thread.
 
 
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Frank S

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Re: 100% off grid shed with Ebay stuff.
« Reply #16 on: August 27, 2014, 07:28:08 PM »
Bruce S; I mentioned what I did about the safeties and the FD because since the OP is wanting his shed 100% off grid.
 As you & I both know and the Op needs to know if he doesn't already, many cities counties & even some states, I won't mention the other, would like nothing better than to  prevent off grid systems.
 In retrospect to this thread My entire system excepting for batteries , Kubota generator & cables was purchased from Ebay.
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Bruce S

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Re: 100% off grid shed with Ebay stuff.
« Reply #17 on: August 28, 2014, 09:38:21 AM »
Frank S ;
It is a perfect time to have said so too!
I am in the midst of looking (window shopping at this time  ;) ) into having our house retro-fitted with about 6Kw of panels.
MO is a state that isn't so nice about giving incentives (we're only at 92/100 rating for sol ) but is actually open to listening. Heck even the mayor is open to suggestions.
We have in place specific SOPs for both types of systems, but as the number of homes and businesses that have solar continue to increase; even those SOPs will need revisiting.
Chicago's SOPs dwarf ours by several 100 pages :-).
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Atokatim

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Re: 100% off grid shed with Ebay stuff.
« Reply #18 on: September 27, 2014, 09:21:21 PM »
Well, I have finally finished my solar tracker and have gotten all the wiring done into the shed.  Depending on the weather tomorrow, I may hook up the panels.

It is time for me to look into using the power produced.  Since inverters are simple, I could go that route, but they are expensive and not very efficient converting 12V DC to 110AC.  What I am interested in is lighting.  My shed is 16ft x 20ft and has 4ea 2 bulb T8? fixtures.  They are 4ft each.  The lighting is pretty good in the shed right now, but with each bulb using 54W each, that comes out to ~1A per fixture which is 4A @ 110V AC.  If I used an inverter, the amperage draw would come out to around 40A draw from the 12V battery bank just to run the lights.

Does anyone have any recommendations on what lighting would do good to replace the 110V fixtures I currently have?  I am pretty sure there are LED ones, but all I have been able to find is drop in LED tubes for 110V applications.

Here is a pic of what the system looks like before I cleaned up the wiring today and secured the panels a bit better (Was missing bolts) :

Frank S

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Re: 100% off grid shed with Ebay stuff.
« Reply #19 on: September 27, 2014, 09:52:39 PM »
I don't  remember the amperage draw but these super bight led dome lights are really bright actually for my way of thinking a difuser cover would tame them a little
http://www.ebay.com/itm/12V-Car-Motor-Auto-42-LED-Interior-Dome-Lamp-Lighting-Bulb-Panel-Super-Bright-/200902211402?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ec6b4774a&vxp=mtr
 I bought 2 of them to replace the CFLs in my Motor home
 the great thing is they are 12 v nominal so no inverter needed to run them
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Atokatim

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Re: 100% off grid shed with Ebay stuff.
« Reply #20 on: September 27, 2014, 10:32:46 PM »
To be honest, that would require too much fab work and I am lazy :)  I was hoping for LED strips that are 4ft long that will output at a wide angle.  I don't want to end up with certain spots of my shed lit up.  I do have sheet rock and it is white inside so light reflection from the walls helps illuminate things even when I am standing with my back to the lights.

Frank S

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Re: 100% off grid shed with Ebay stuff.
« Reply #21 on: September 28, 2014, 02:20:51 AM »
there are rolls of LEDs that can be cut to length just solder leads to the wires and go
 But the dome lights really don't require any fab work just use double sided sticky tape and run a pair of 18 to 22 ga wires  depending on distance from power source .
 I have 2 of them for my tool& parts van but want daylight bright when tinkering on stuff so will probably install a total of 8 in the 26 by 8 ft by 9 ft ceiling van with maybe some smaller ones under the shelf over the work bench
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Mary B

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Re: 100% off grid shed with Ebay stuff.
« Reply #22 on: September 28, 2014, 03:16:38 AM »
MR16 led spotlights, bi-pin base so would have to get sockets http://www.amazon.com/Great-Eagle-Replacement-Certified-Lighting/dp/B00GRPACDW/ref=pd_cp_hi_3