Cheap solar setup for shed

[kf4zht]

Calling the Solar Experts:

I have a 20x20 shed/barn about 100 yards from the house. Long term plan is to run 100amp service out there, but that is down the road in terms of cost and other necessary projects. Currently I use it for storage (car, lawnmower, generator, misc shop tools) and it would be nice to have power down there, main uses would be:

Battery Chargers
Lighting (florescent or LED, not installed yet)
Occasional Saw or power tool
Fan

When I have a big project I can just crank up the generator. There are no overhead trees, it gets plenty of sun. I was wondering what a good basic solar setup would be, and what the approximate cost would be. Thinking something along the lines of 1-2 panels, a charge controller, a couple deep cycle batteries. I have an inverter that will run lights or power tools already.

Is something this simple all I need?

http://www.amazon.com/dp/B00BFCNFRM/?tag=atomicindus08-20

+

A couple deep cycle batteries from wally world?

 

[Craptain]

First of all you need to run some numbers. Look at your needs and work out how much power you will need. The allow for the losses in your inverter, I would use at least 20%. That will give you a starting point. Then you know what size and number of panels you need. This will at best be a good guess, but as you have a generator it is not to big a deal. It is probably worth getting better batteries than Wally World, or maybe not depending on your time frame (how long you want them to last). The kit you linked looks to be a fair price for what is included. If you need more power they do a larger kit which includes the extra panel(s) at a discount over the unit price. It would be nice to know where the panels were made. I suspect China.

 

[wb2vsj]

Try before you install. Some tube florescent lights don't like "modified" sine wave power (i.e. square wave) and you'll need a sine waver inverter. (i.e. more $$) I've run some CFL's off a regular modified sine wave inverter and while they do work better than the tube lights, they get hotter than normal and smell like it too.

Haven't tried the new CREE LED ones yet (Well, I have but it was a very early cheapo LED 15 watt-replacement bulb from about 5 years ago and it ran fine.)

 

[Daniel Dudley]

I was at a job site last week, and I was running a high draw compressor off of 250' of 10 gauge extension cords from a 20 amp circuit at the house.

You should price out the cost of underground cable and a panel. It could be less than you think. Or at least consider doing one 20 or 30 amp circuit.

It really isn't worth making do, when you need power. I am running a 100 amp panel box off a 50 amp breaker in my house, using 6 gauge service entry cable . The box only cost fifty bucks at a box store. I had the wire from a remodel, but really I didn't save that much. I could go to 100 amps any time I want to spring for the wire, but so far I haven't needed to. Check out the price of a direct bury cable.

It changes your life.

 

[theoldwizard1]

Forget running power tools off of an inverter. The pseudo-sine wave inverter make for less efficient operation. You can not afford a sine wave inverter to run power tools ! Use your generator.

With a 300 watt inverter you can run a box fan, some florescent lights and maybe a laptop or cell phone charger. Check the wattage on any other chargers. I don't know what a typical cordless power tool battery charger draws.

At 300 watts, you are pulling more than 25A out of a 12V battery. At 1000 watts it is well over 80A !

Get the biggest deep cycle batteries you can afford. Going 24V is a good idea.



Sounds like you want to stay in the "hobby" end. A true off grid system with only 5,000 watts capability would run you well over $10,000.

Quick, very rough, rule of thumb. If you are charging your batteries at 100w/hour for 12 hours and discharging them at 300w/hour, with 100% efficiency you should get about 4 hours. In reality, you would be lucky to get 2 hours. Obviously less draw, longer run time.

 

[where2]

Haven't tried the new CREE LED ones yet (Well, I have but it was a very early cheapo LED 15 watt-replacement bulb from about 5 years ago and it ran fine.)

I have run a new Cree 60W equivalent warm white (9.5W 800 lumen, sells at HD for $13-$14) off a MSW inverter, and it worked fine. Used the little Black & Decker air pump/inverter/jump starter unit I keep in the trunk of my car.

I've dabbled in solar a little, I have a 4400W grid-tie PV system on my roof (designed, permitted and installed by me). I keep some little 20W and 50W low voltage panels around to charge batteries.

 

[HOTFR8]

My first Solar system here was two 80 watt panels. Two 6 volt batteries and an invertor. That runs my computer, phones, fax and answer machine as well as a few basic lights over the desk. That system also has a battery tender that runs from the mains as a top up. This is a stand alone system and if the power is off I can still keep working.

Later I added another 24 (120 Watt) panels so the whole property now runs on Solar and back feeds to the grid. This system also runs if the grid fails as it has two 24 volt batteries. I also have a small Diesel Gen set that I can use if we have power outages or bad days.

You need to work out what you need your system to do and design it or have it designed to suit what you want it to do. The smaller system was very easy to set up and the bigger system ver profeesional. Remember you want quality items if the system is to work.

 

[hh76]

If utility power is near, it will almost always be cheaper than to install a battery system, especially one that would need the capability to run a fan, which typically uses a fair amount of power, and is on for extended periods. I'd say you'd be looking at around $750 or better if you wanted to do it right.

If it were me, I would look into very small system just to run a few LEDs, and count on the generator for the rest. Take the money you'd save and put it into a saving plan for running power to the shop.

you can rent a trencher for about $50, 1.5" pipe is about $0.50/ft, and wire would cost around $4/ft. I'd say if you did it yourself, it would cost you about $1500 to have a nice, 100a setup.

 

[HOTFR8]

If you go with a small 12 volt system you can always use the inverter from your car. My experience with what I have here is the smaller 12 volt system can easily be moved. The bigger 24 volt system is fitted.