Introduction: Adding a Harbor Freight 45 Watt Solar Panel to My Storage Building

Picture of Adding a Harbor Freight 45 Watt Solar Panel to My Storage Building

Earlier this year we bought a 10' X 20" storage building and had it delivered to the backyard. The storage building is great - I'm slowly moving things from my garage to the building, I'm doing this slowly because at the end of the day I don't want everything thrown in the building - I want some organization.

One problem with the building is long before it gets completely dark outside it's so dark inside that I can't see anything. It's cost prohibitive to run power to the building so I decided to do the next best thing - solar powered lighting. For an application like this you really don't need a lot - you need to collect enough solar energy to turn on the lights maybe 15 minutes when you need them? But you also need enough energy to carry over cloudy days.

Also, my direct view of the sun is limited from the roof of my storage building by trees so I figure I'll get an hour or two of good strong sunlight a day. This meant that I probably could not get away with a small 15 watt solar panel.

I ended up buying a Harbor Freight 45 Watt solar panel kit and you can find my full write-up of this kit in this instructable.

Step 1: Install the Solar Panels

Picture of Install the Solar Panels

Installing the solar panels is pretty straight foreword. Because of the type of roof on my building I could just mount the panels with some outdoor rated screws. I was careful to mount one side of the panel through one of the ridges of the roofing and this placed the other side of the panel just inside a ridge.

Before anyone comments about the mounting angle I already know that these are not mounted at the ideal mounting angle for solar energy. But I'm not concerned about harvesting the maximum energy from the sun, I'm just using solar energy to light the inside of my storage building.

Step 2: Getting Power Inside the Building

Picture of Getting Power Inside the Building

To get power inside the building I drilled a couple of holes under the eaves then I fished the wires through. I'll pick up some silicone calk for the holes the next time I'm at LOWES.

Step 3: Hanging the Lights

Picture of Hanging the Lights

This kit came with a couple of nice 5 Watt florescent lights, each with its own 16 foot power cable and switch. I'll wire both to a switch near the door but for now I'll use the in-line switches that came with the lights to turn them on & off.

I mounted one in each end of my building.

I used plastic staples to hang the wiring, available just about anywhere that carries minimal wiring supplies - I bought this pack at Wally-World for less than $2.00.

Step 4: Final Wiring

Picture of Final Wiring

For final wiring I cleared off some shelf space for the controller and battery then I ran all the wiring to the controller.

I could have placed the battery on the shelf behind the controller but I wanted the battery out front so that I could easily remove the cell caps and check the electrolyte (water) levels.

In the last picture you can see the two black switches for the two florescent lights.

Step 5: End Result

Picture of End Result

You can see the solar cells mounted to the roof of my building.I'll know tomorrow after a full day's charging how well the lights work. But I suspect that my old marine battery is too far gone and I'll need to replace it.

If I decided to get really crazy with solar power I could mount 10 more panels to this side of my roof for a total of 195 watts!!! But what would I use it for?

You can find my full write-up of the solar panel kit I installed in this instructable.

Step 6: 09/09/2014 Update

Picture of 09/09/2014 Update

I took a few pictures tonight. The lights are not as bright as my cellphone camera makes them out to be but there is plenty of light from the two florescent lights to see everything inside the storage building.

Also, I looked up the amount of sun available in North Alabama and the average sun hours / day here is 4.43. This number means that throughout the year the sun is shining bright for an average of 4.43 hours a day. This is an important number because it tells you how much sunlight you have to work with.

For example, an average of 4.43 hours a day X 45 watts = an average of about 199 Watt hours a day (4.43 X 45 = 199.35). But that's what the solar panels can produce, then you loose some charging the batteries, etc., and that total loss is probably 30%. This means that long term I can count on 139 watt hours a day (199 Watt hours X 70%).

The two lights together consume 10 watts and "in theory" I could run them almost 14 hours a day off solar power (139 watt hours / 10 watt load).

.

Comments

JoeB373 (author)2016-12-27

I bought the same system to light three outbuildings and charge their batteries - as well as trickle-charging my generator battery. Worked great for about 4 years in AZ sun, then stopped charging. I learned that these amorphous-type cells only last about 3 or 4 years.

Moseley JasperT (author)2015-12-01

I have had these for a year now. One set is the only power needed for my driveway gate well the battery to lol. I just used a marine 12v battery there. There is one powering two lights under the carport with 2 6v golf cart batteries from advanced auto, and about to do the same setup for outside Christmas lights on my home. Well worth it. A lot lf freedom with'em just do NOT plug in anything that does not have a three prong plug unless you buy a sign wave

Hello

Just getting into solar and wondering why the 3 prong is a no no and why you'd need a sine wave and what you mean by that. Thanks

Thanks for the comment. Other uses since I've installed my solar panel:

I'm using my existing setup to float charge my lawnmower battery over the winter.

I'm planning to add a small decorative pond and will use solar power to run the pump during the day.

Sorry thats sine wave I think.

PaulChau (author)2015-12-27

I think that we should all try our best to make a difference on our power consumption and installing a solar panel is a wonderful way to do our part!

techie66 (author)2015-06-24

Great project !

Do not try to use more power out of your battery than 20%, that will extent the battery life, and not leave you in the dark if you have some bad weather over a few days, remember for every watt you take out 1.5watt has to go in.


Grtz

JasonO1 (author)2014-09-15

I use a Harbor Freight 45-watt kit for my shed as well. It works really well. A couple of times I left the lights on. Even with the lights on all night, the battery still kept charged. Two modifications I'm planning on: 1) My kit didn't come with a switch for lights. I have to rig one somehow. 2) My shed gets hot. I do have a screened window but it doesn't help that much. My plan is to get a 12 volt 120MM computer case fan and rig it up as an exhaust fan. You can pick those up fairly cheap.

Tom Hargrave (author)JasonO12014-09-15

A 12VDC PC cooling fan is a great idea! You could even control it with a cheap mechanical home A/C thermostat, the type with contact springs. You could set the thermostat to turn power to the fan on once the inside temperature crosses a predetermined point, something like 95F.

leamonwilemon (author)2014-09-09

Where did you get that shed?

I bought the building from Backyard Outfitters in Fayetteville TN - 931-297-5060. If you are local you will see them on the left not long after you get into town, assuming you are heading North on 231/431. We looked at a lot of them and their storage buildings are very well built.

https://www.google.com/maps/@35.1397394,-86.567686...

LOVE this building and I live in Middle TN, so I can make the trip to Fayetteville. I've been thinking of adding a shed behind the house for my craft room, but had the same problem as you (didn't want to run electricity AND live on a wooded lot with limited light). This was great info for me! Thanks for the post.

One thing I learned already is my old marine battery is too far gone but I thought it might be. The battery won't hold a decent charge overnight even after being charged by a good 15 Amp plug-in charger. I bought a small garden tractor battery and I'll put it in Monday morning.

I also know from watching the voltmeter on the charge controller that once the sun goes behind the trees the battery charges very little. But I intended this project to provide light when I'm in the shed in
the evening getting stuff and putting stuff up and I won't have the lights
on very long.

You may find that, depending on how much direct sunlight you have and how long you want to run the lights, you need to add solar cells to provide the light you need.

Thanks for the reply. I am not local, but am in the market for a new shed.

djuan1 (author)2014-09-14

cool projects I'm in N Alabama Too

uncle frogy (author)2014-09-14

I being a little paranoid about things like leaks and strength I would have attached the panels to a metal or wooden cleat that was attached to the roof on the top of the roofing's ridges. great project

uncle frogy

Tom Hargrave (author)uncle frogy2014-09-14

That appears how all the other solar panels are mounted. They have an
aluminum frame that takes a fastener from the rear. These panels have a
plastic frame, or at least a plastic cover, that makes mounting from
the front easy.

If these panels were going on a house or another
building with a water tight roof I would mount them the same way. As
they are mounted the top 2 screws are protected bu the top roof section
overhang and if I see any signs of leaking past the bottom screws I can
reach in & seal them with RTV without removing the panels.

FuzzyBearGeek (author)2014-09-14

I would love this as a house.

The building would make a cute cabin once you add insulation and close off the two large doors.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

Tom Hargrave (author)Ralphxyz2014-09-14

Given the capacity you could store enough energy for just about anything short term, but you need to consider that all batteries have a internal self discharge rate and lead acid is about 10% per month. This means that you could increase the capacity to the point where your solar cells will no longer keep up with your battery's internal discharge rate!

jim_lewis1 (author)2014-09-14

Did you think about this option? Maybe save the solar power for darkness:

https://www.instructables.com/id/How-to-build-a-SOLAR-BOTTLE-BULB/

Tom Hargrave (author)jim_lewis12014-09-14

This won't help my situation. I get plenty of light when the sun is up, my issue is light when it starts getting dark.

Stavros! (author)2014-09-14

I think you're overlooking something, you don't have to stick with the Harbor Freight panel, you can buy higher output panels for the rest of the space, increasing the output.

Tom Hargrave (author)Stavros!2014-09-14

I agree and I'm already looking at other solar panels. So far I've not seen anything as easy to mount as the Harbor Freight panels. Because of their design these just mount with screws through the top and bottom.

Jack Rodgers (author)2014-09-14

LED light bulbs are extremely energy efficient. I light up my van at night using a 40 watt equivalent and a 4 bulb GE Light bar. About 10 hours of use drained my battery about 30%. I recharged during the day.

The solar panels should have shipped with a converter for storing to a battery.

The kit did ship with a converter for managing a battery and I did a full write-up of their kit here.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

Ralphxyz (author)2014-09-14

re: "But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge."

That would depend upon your storage, the 195 watts total is your output of your solar panels. If you had ten batteries you would have more wattage capacity.

You could use up your storage and the panels might take a couple of days to recharge the batteries to full capacity but if you are not using the charge constantly through the day it should work.

It would not work for a constant load like a freezer but you could power your lights and some power tools.

jmwells (author)2014-09-07

As a professional electrician, not bad. I recommend that you put something between the panel wires and the metal edge, some split hosing maybe. The wind and sun will eventually wear through the insulation. Putting the battery on a plastic tray is also a good idea. Or in a box with a vent tube outside.

wkearney99 (author)jmwells2014-09-14

Or a marine battery box, like the kind you'd use on a boat. If/when the battery has problems you'll avoid damaging the shelving. That and batteries require maintenance, some more than others.

Tom Hargrave (author)jmwells2014-09-07

Thanks, I agree, but at this point I'll find some rubber tubing. slit it and slide it over the edge of the roofing.

I also used to be an electrician before moving on-to and making one of my hobbies - electronics - my career.

kakashibatosi (author)2014-09-08

some more capacity mint give you enough power to operate some tools for a while, or perhaps you could power a spare refrigerator in the event the power goes out.

I considered this - I even have space for 10 more of these solar cells on the section of roof I have these mounted on. But even with 13 total solar cells I'm only looking at 195 watts total, and that's at peak charge.

With that kind of capacity maybe you could deal with a smaller chest freezer. There are lots of power saving options

https://www.google.com/shopping/product/1138627247...

this one claims to be designed for use with solar power. It's nice to know that you'll have even some electricity if all else goes down. Hope you'll keep updating as you add more things!

I chased this freezer down and it needs at least a 215 watt solar panel. I'm short by quite a bit.

Darn! That's too bad. Oh well, good to know. There's bound to be an option that works well for your situation and I'm sure you'll happen across something perfect. Best of luck in all of your solar endeavors!

Thanks, I'll check out the link when I get home.

amulder1 (author)2014-09-09

Did you just screw 12 screws through your waterproof layer? Did you do anything to seal those holes afterwards?

Tom Hargrave (author)amulder12014-09-09

There is no waterproof layer. This is an outside storage building with metal roofing put down over outdoor grade plywood. I did make sure the top edge of the solar panels were tucked under the lip of the upper sheets of steel.

I probably should make it clear that you should not install solar panels on your house roof this way!

longwinters (author)2014-09-09

A window would help, installation company's often mis- measure and practically give away the wrong sized windows, a 32x24 vinyl slider would let in both light and air, cost ya 20.00 bucks

Tom Hargrave (author)longwinters2014-09-09

I already have 2 windows, doesn't help much when it's getting dark outside.

MrFrancis (author)2014-09-08

Thanks for the post. I'm not an electrician, but love starting fires with wires! Lol