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Small Cabin Forum / Off-Grid Living / No to Solar
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rachelsdad
Member
# Posted: 5 Mar 2016 05:54 - Edited by: rachelsdad
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Well in reviewing photos of the place...there is pretty heavy canopy from 50-80' pines blocking southern sun on my roof...or really anywhere save for the dock which is 100' away.

My gut after reading through tons more info on these very forums:....2 deep cycle 6v golf cart batteries charged by a Honda eu2000 and a Iota or Samex charger. May be a few bucks more than I would like to spend but I want it to be bombproof.

Again, using 14 g romex, 20 x 12 volt LED lights, (I am way over estimating at 20 fixtures).....9 watts each..a shurflo 12 v water pump and that is pretty much it for power requirements.

I will not be drawing water like I originally thought...will collect rainwater...but I can always pump if needed

Or: Same set up but go w/an inverter and use 120v LED bulbs...

Weekend use for the most part...summer for majority of time...so lights run what 4 hours a night?

Am I going to be living with my generator running 24/7????

Julie2Oregon
Member
# Posted: 5 Mar 2016 07:04
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What about food refrigeration/preservation? That's probably the biggest electrical use.

I'm going to be living at my cabin full-time but I've nixed a fridge for now and will have a chest freezer. In a survey of my on-grid fridge-freezer, I don't have nearly enough freezer space and what's mostly in my fridge are dairy products, eggs, iced tea and condiments, lol.

So, what I'm doing is buying one of those party/patio coolers -- the kind that's a cooler inside a decorative wood box on a stand with a wood lid lined with metal. I'm going to fix racks on the bottom and sides in which I can slide either freezer packs or blocks of ice (frozen in my freezer) and that will keep my dairy and beverages cold.

I'm single, buy in bulk because it's less expensive, and then break down and package everything in single portions and pop them in the freezer. Then I just thaw exactly what I need for a meal. A freezer is a big deal for me; a fridge, not so much. If it's a choice of what to spend my watts on, it's a no-brainer. A chest freezer also uses less electricity than a refrigerator does.

But you'll need something for food and power enough to reliably run it.

rachelsdad
Member
# Posted: 5 Mar 2016 08:09 - Edited by: rachelsdad
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Hi Julie,

Luckily there was a 2 yr old propane fridge....so again, my electric needs are few..but trying to make it user friendly

Still researching if it makes sense to keep it running while we are not there or haul perishables back and forth.

I plan on being there every weekend...your set up would be ideal if I did not have the fridge in place...great touches!!

Steve_S
Member
# Posted: 5 Mar 2016 08:42
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If you do not "need" 120V for anything specific, a good 12 Volt system should do pretty much anything you need. to invert from 12 VDC to 120VAC your losing in converting up and losing again in converting down (where needed).

Most any sm appliance, device, gadget or gizmo is available in 12 VDC. For certain use the Honda 2000 Inverter Genny for charging your batteries but do have a look around and see if you can accommodate a couple of panels...

Have a look here @ 12volt-travel.com and you'll see that 12VDC goodies are out there and if you shop on E-Bay & Amazon check out RV & Marine suppliers for heaps of goodies.

rachelsdad
Member
# Posted: 5 Mar 2016 10:03
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Steve,

I was heading full speed to 12 volt but the more I looked into it apparently my original idea of 14g romex and standard outlets to accommodate standard house lamps and 12v led bulbs leaves a bit to be desired as the outlets are not compatible w/12v.

I'd really prefer to avoid lighting fixtures that look like 12v.

To add to the list...reviewing pix this morning the trees (very tall and wide), will make solar impractical w/out running 100' f line to the battery...something I prefer to avoid for cosmetics...

Clipper
Member
# Posted: 5 Mar 2016 12:58
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100 foot distance to panels is not a complete failure. If you run your panels in series and use a MPPT charge controller you should be fine. I used 10 gauge wire to run 90+ feet with two 260 watt panels in series for ~ 70 volts. the voltage loss was minimal and works great. I needed the distance to get to the lakeshore to get a clear shot to the south due to too many trees as well.

Without solar i think you may get tired of using your generator every day. I have a honda 2000 generator that i use to supplement charging on successive no sun days and that is quite enough.
panels at the lakeshore
panels at the lakeshore
panels at the lakeshore
panels at the lakeshore


MtnDon
Member
# Posted: 5 Mar 2016 14:02 - Edited by: MtnDon
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Distance is conquerable, though it may mean spending more money. An MPPT charge controller is needed, using a couple or more, "24 volt" PV panels in series. MPPT can reduce the needed wire gauge. We have a run of 325 feet.

For me, anything I cando to reduce or eliminate the need to operate a generator is worthwhile.

razmichael
Member
# Posted: 5 Mar 2016 18:09
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Quoting: rachelsdad
I was heading full speed to 12 volt but the more I looked into it apparently my original idea of 14g romex and standard outlets to accommodate standard house lamps and 12v led bulbs leaves a bit to be desired as the outlets are not compatible w/12v.

I'd really prefer to avoid lighting fixtures that look like 12v.

I assume when you state "outlets" you are talking about switches? Really not a major issue. The arcing issue is not serious - keep the amperage on the light circuit minimal and use 20 amp switches (slightly more expensive than 15 amp switches but not much - example ). Make sure you use a toggle switch that clicks (faster switch than the panel switches). The risk of the switch fusing is very low and if it did happen, replace the switch (a lot cheaper than a dedicated 12v switch). I've been 3 years like this without an issue. All my research found lots of people doing the same for many many years. If you have a bunch of lights on one switch, this is different. The advantage of less bulbs per switch is that you can only use the minimum amount of light you need (although wiring costs is up a bit).

Voltage drop is something you also need to be concerned about for any sockets or lights at the far end of the cabin. Lots of online calculators such as Voltage Drop . Again this is reduced by using less lights per circuit but be careful about any circuits that need or might need to power something more than a light or two. In this case you may need to use heavier wires. Even more of a problem if you are running three way lights switches because of the longer runs.

rachelsdad
Member
# Posted: 5 Mar 2016 19:26
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Quoting: razmichael
I assume when you state "outlets" you are talking about switches?


Actually I was told the outlets...but I was told later this morning at a local battery shop that is poo poo.

Then I run into an electrician who said just run an inverter...blah blah blah...

He said my math was fine but he had no experience w/12 v.

So what would I need, 2x 260 watt panels to keep my 2 golf cart batteries humming plus the MPPT controller?

Quoting: Steve_S
to invert from 12 VDC to 120VAC your losing in converting up and losing again in converting down (where needed).



How big of a loss are we looking at here? The idea of an inverter/charger makes some sense...


Such fun.

Thanks everyone for the patience w/me....you're all invited up...or down...when it's ready!!

BillMac
Member
# Posted: 22 Mar 2016 22:24 - Edited by: BillMac
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12 volt system = bad need huge thick gauge wires. 24volt is better but 48 volt system is best. Power loss is your enemy and so is heat. Higher the volt more efficient the system. Mono solar works awesome in full sun withan MPPT charger. Spending money on PWM charge controller is ok for learning but a waste of money. Example of a Nightmare setup 12 volt car battery and 45 watt amorphous panel from harbor freight with a cheapo 7amp pwm charge controller = burnt out system that doesn't do anything but charge a cell phone or give you a few hours of light at night. Been there done that. I lost money that could of been put into a real system that works. Example of the right way to do it = Mono or Poly( cheaper less effective panel) Mppt charge controller and 4, 8 or 12 6volt amg batteries set up in 24volt or 48volt configuration with a decent inverter ( modified sine wave to run tools and pumps and a Pure sine wave to run your phone, laptop and other sensitive equipment.) Most of your money is put into a single big panel (200 to 380 watts) next buy your charge controller Mppt then buy as many Deepcycle agm as you can afford bought in pairs. Small awesome efficient decent system can be put together under $1,000 but its worth the tax return cash put into it in the long run. This will run Led lights, coffee makers, laptops and pumps for a short time. (running things like pumps or refrigerators look into adding a 500uf Capacitor to help jump start those items built into your system to make it more efficient and less damaging to the system. Use Fuses to help lessen shorts, accidents and size them to your systems needs. Learn to Ground your system or risk it burning up in a lightning strike or plasma melt down if you drop a metal tool in the battery bank. Be smart wear rubber gloves when working on anything and always disconnect power. Huge breaker switch, and add in a small light some where to tell you the systems on. DO not drain your Batteries below 50% or you lose the Battery bank and damage it forever If you build it right the first time it'll last and provide for you. Think about it.

littlesalmon4
Member
# Posted: 23 Mar 2016 11:49
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If your panels need to be a long distance away and you really seem to want 120 volt AC anyway my suggestion would be to build a very small shed to mount your panels and house your batteries and inverter. Convert the 12 dc from the panels through the inverter in the shed to 120AC then make your long wire run to the cabin. You can run 120 ac through smaller diameter wire longer distances. This I believe would be the most efficient and cheapest especially considering wire cost.

rachelsdad
Member
# Posted: 26 Mar 2016 08:03
Reply 


Quoting: Clipper
I used 10 gauge wire to run 90+ feet with two 260 watt panels in series for ~ 70 volts. the voltage loss was minimal and works great.



hmmm..I was under the impression 2 gauge for a run that long...no issues w/10??? I was thinking of running the line up and over to the house on my trees...ala telephone/power poles.

littlesalmon...great idea!!!

Clipper
Member
# Posted: 26 Mar 2016 15:39
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There are voltage loss calculators on line. Just enter the voltage that your panels in series will deliver, wire gauge and distance and it will give you the estimated loss. Try to Aim for a maximum ~2% loss for efficiency.

But really all your dealing with is efficiency of getting maximum power to your charge controller so a bit larger loss may be an acceptable variance given the cost of wire and other factors. I used 10 gauge weather proof burial wire for the 70 volts max generated from my panels to go around 90 feet and I think it was estimated about a 2% loss.

In any event it works really good and allowed for all components to reside in a power shed and then wired the ac and dc circuits into the cabin. When monitoring the trimetric it appears that very little loss was realized as the panels appear extremely efficient.

rachelsdad
Member
# Posted: 26 Mar 2016 19:16
Reply 


thanks Clipper...makes so much sense.

Funny, I had people tell me my idea of using the trees to run the wires was a bad idea..."what if they blow over??"..they are over 100 yrs old...I'll take that chance!

Thank you very much

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