Another power supply question

[Northwoods]

In this case for our chicken coop.  Need to run power for lights, heaters for the water in winter.  Plus ability to run a tool like a circular saw.

It's 100' from the house to the coop, and maybe another 40-50' to the panel.  What's the best way to do that?  I'm not a natural for working with electricity, so don't assume much prior knowledge.

[dogmush]

120vac,  15 Amps, 150ft run calls for 8AWG wire.

Although, at already running 8 gauge, I'd run a 30A 240 circuit and a little sub panel. Then you'd have plenty of heater power.

[Northwoods]

Heater only draws 50 watts.

[dogmush]

You're going to want 15A to run a circular saw.

[Northwoods]

Downside to 12ga?

[zxcvbob]

Downside to 12ga?

There's no downside until you try to use the circular saw, then it will bog down from the voltage drop.  Have you considered a cordless saw?

[Ben]

There's no downside until you try to use the circular saw, then it will bog down from the voltage drop.  Have you considered a cordless saw?

Yeah, it's kind of a big jump from lights and a coop heater to a circular saw. Unless you think you have need for other big stuff, I'd use a cordless circular saw there. Then again, if you're running power anyway...

[dogmush]

My handy dandy wire size calculator says that 120vac over 150ft 12awg is only good for 6 amps (with 3% voltage drop)

I'm not even sure if you can run a 6 amp circuit and put a duplex plug in it under code.

There are 50 watt solar panels pretty cheap these days. A couple hundred bucks could get you a panel, a couple LiIon batteries, and some LED's for light, then hook up a little coop heater. With what copper costs these days it might even be cheaper, and you wouldn't have to dig a trench.

[Hawkmoon]

Downside to 12ga?

Voltage drop. Run 10-gauge, minimum. Technically, at 3% voltage drop 10-gauge is good for 71 feet, 8-gauge is good for 157 feet.

[Ben]

There are 50 watt solar panels pretty cheap these days. A couple hundred bucks could get you a panel, a couple LiIon batteries, and some LED's for light, then hook up a little coop heater. With what copper costs these days it might even be cheaper, and you wouldn't have to dig a trench.

I've seen quite a few setups like that. Harbor Freight has 100 watt panels that go on sale at least 4-5 times a year for around $150 (sale price). Batteries too. I'm guessing in Sumpnz climate, that water bowl heater won't need to be on a great deal. I guess a question is the lights. Are they LED just for light for egg production, or are they going to be incandescent for light and heat? The latter will start drawing power quick depending on how many bulbs and the wattage. Otherwise solar would be a great choice for say 50 watts heating plus 10-15 watts of light a few hours a day.

[Northwoods]

I had been thinking about solar, but wasn't sure how to size it.  For that 50W heater and a couple LED bulbs (don't need to heat the coop itself), plus enough heat tape to keep exposed pipe/hose (insulated) from freezing, would a 100W solar power system be enough?  I'm at 48.5°N.  How much battery capacity should I plan on?  Assume the water heater is only on at night, same with lights, so it'll all come out of the battery, none will be direct from the solar panel.  This will also only be in use during winter.

Worst we've had it in 8.5 years we had 1 week of sub-freezing weather.  We've hit 10°F a time or two, but very briefly.  Most of the time it never goes below +20F overnight.

[Ben]

Would the lights be on all night? Not that I'm a chicken expert, and I just give the chickens here a break in the Winter, but my understanding is that it's best for the chickens to do like 15 hours of light and to just have the coop lights come on via timer early (like 0400ish) in the morning to not stress out the chickens.

[Northwoods]

No, probably not all night.  Probably a few hours in the evening.  Might even be left off except when we are doing stuff in the coop.

[Hawkmoon]

I don't think you're going to run heat tape off a 100-watt solar panel. A 12-foot length draws 84 watts at 120 volts.

https://www.lowes.com/pd/EasyHeat-AHB-12-ft-84-Watt-Pipe-Heat-Cable/1068425

[dogmush]

Well hell, I'm board at lunch.

Winter Solstice is Dec 21 this year.  At 48.5N there is 8 hrs and 15 min of daylight that day.  So 15:45 of darkness. (worst case)

Coop heater: 50W  50W/12VC= 4.16A

There exists Low Voltage heat tape. Let's assume that you aren't heating the entire pipe, just the part above ground, so like 10 ft?  5W/ft*10ft=50W  50W/12VDC=4.16A

16 ft of LED Strip (waterproof) says it needs a 2A power supply at 12VDC.

Heater and pipe warmer together is 8.32A* 15.75 hours on the solstice=131.04AH

Lights @ 2A for 4hours and 41 min (0400 until 0841 (sunrise on the Solstice)=9.5AH

Total=140ish AH.  That's a fair amount of power, actually. A couple of 100AH Sealed AGM Batteries would work.  Lithium get's expensive fast.

Now you need a solar panel capable of charging that in ~8ish hours. 140Ah@12VDC is (I think) 1,680 Watt Hours. 1680Wh/8.25hrs of daylight=203 watts (average, for the whole day)  KD5NRH probably wants to step in here as there are a ton of variables in panel output, but my understanding is that they are rated in under "Ideal" conditions (that is Noon, at the equator kinda conditions)  So you'd need some extra capacity.  Maybe 4 of those 100W Harbor Freight panels?  Two of these, maybe?  That's getting into $800ish to set up.  I did however pick the worst day for solar.

[Scout26]

That doesn't factor in clouds and rain, and Sumpnz is near Seattle IIRC.  So I would cut any sunlight available in half, as, again IIRC, the amount of power produced by a solar panel is greatly reduced by lack of direct sunlight.


I would go with 8ga wire run, and an outlet (or two) on a seperate circuit.  Yeah, you may not be able to run a circular saw,  but for light duty "stuff" you should be okay.

[dogmush]

Although, at already running 8 gauge, I'd run a 30A 240 circuit and a little sub panel. Then you'd have plenty of heater power.

From post 2.  Only really needs one more run of wire, and then he can run whatever he wants out there.  Build a tiny house even. 

Kinda depends on how bad he does, or does not, want to run a permit, and how much one cares about "doing it right" and "code". 

Someone will be along soon to suggest this anyway: https://www.amazon.com/Yellow-Jacket-2806-Heavy-Duty-Contractor/dp/B0009IAXSW/ref=sr_1_2_sspa?s=lamps-light&ie=UTF8&qid=1540837238&sr=1-2-spons&keywords=100+ft+extension+cords&refinements=p_n_feature_keywords_two_browse-bin%3A7065065011&psc=1   

Although now that you mention Seattle, maybe we could get a rain cistern, waterwheel, some kinda of geared generator and some batteries......Hmmmm.


Seriously though, if you want circ saw kinda power that far away from the panel, run the 8AWG. Voltage drop and heat build up will be an issue.  Once you pull a permit, dig a trench, lay conduit, fill with three strands of 8 AWG copper and put some weather tight outlets, just run a 30A 240 circuit (assuming your breaker panel has space).  No one ever finished an electrical project and said "Damn I wish I didn't have all this electricity out here."

[Ben]

Although now that you mention Seattle, maybe we could get a rain cistern, waterwheel, some kinda of geared generator and some batteries......Hmmmm.

KD5 is that you and what have you done with Dogmush?