Assembling My Harbor Freight 45 Watt Solar Panel Kit - No Tools Needed!

I originally wanted to design my own solar panel controller then buy the "best deal" in solar panels out there I could find. While doing my research I kept coming back to the Harbor Freight 45 Watt solar panel kit because it looked like for less than $200 (at the time) the kit would do everything I wanted to do with solar power.

I found a lot of bashing on-line about these kits so I read through the BS and the three major complaints were:

The controller is simple and does not use PWM to charge the battery.

But it's a 45 watt system for less than $200. What do you expect for less than $200????

It's only 45 watts.

This is OK for me, I'm planning to just run a couple of lights and maybe a fan and none of these will be on for very long.

The controller that comes with this kit does not include a low voltage cut-off needed to protect the battery.

This is absolutely not true and I found the schematic on-line to prove it's not true. Then I took the cover off the controller to analyze the circuit myself to verify the schematic is correct. This controller does include a low voltage cut-off to protect your battery from over discharge.

The positive points were the kit seemed to have everything I need except for a battery and maybe a power inverter! Also, everything appeared simple to hook-up.

I wrote this instructable as a review of Harbor Freight's kit, but the real reason I bought the kit was to install solar lighting in my storage building. You can see the full install in this instructable.

Step 1: I Bought and Unpacked the Harbor Freight Kit

I finally had about $200 to spare and I bought the Harbor Freight kit. My first surprise was how heavy this kit was - it's almost 60 lbs!

Next I unpacked the solar panels - each solar panel was protected by a pair of styrofoam panels. I also discovered why the box weights so much. The solar panels are very heavy for their size.

The next surprise came when I unpacked the tubes that assemble into a frame. I expected some cheap thin PVC tubing. What was in the box was still plastic but the plastic was very heavy. Also, everything was clearly labeled.

The other major parts - the controller and light were packed in a box inside the main box and the interconnect wiring was in with the plastic frame parts.

Step 2: Assembling the Frame

The kit comes with two sets of screws & wing nuts. The shorter screws are used to assemble the frame. Everything goes together like the picture on the outside of box and like this instructable title says - no tools needed. You just drop the screws through the holes then tighten the wing nuts. A philips (cross tip) screw driver won't hurt if you want to snug everything down tight, but it's not absolutely necessary.

Step 3: The Working Parts of the Kit

Like the box says - everything's included except the battery and a power inverter (assuming you need one), but I don't need one because I'll be using the two 12VDC florescent lights included with the kit.

Step 4: Solar Panel Assembly

The solar panels themselves attach to the frame with the same style screws and wing nuts that are used to assemble the frame, only they are longer and include a small flat washer. The panels each attached with four screws, 2 on the top and 2 on the bottom.

The frame itself has two swing out legs and you set their angle with two of the screws left over from assembly. This makes it easy to set-up the panel, then take it down when not in use. If you like camping it would be easy to stow this somewhere in your Vanagon or camper then drag it out and set it up in just a few minutes. A philips (cross tip) screw driver won't hurt if you want to snug everything down tight, but it's not absolutely necessary.

Step 5: Wiring It All Up

Wiring is simple - it's all "plug and play".

The three solar panel cords plug into the 3 way adapter that comes with the kit and you can't plug the wires in reversed. Then the main cable plugs into the other side of the adapter.

The ring terminal end of the cable attaches to the solar panel side of the charge controller back panel. Everything's color coded and just like the first part there's "no tools required".

The battery charge cable attaches the same way.

I was concerned about cable length so I stretched the solar panel main cable down my driveway and measured the length. The longest tape measure I have is 25' but based on the length left over, it looks like the overall stretched-out length is 30'. This means you can park your camper or Vanagon in the shade and drag your solar panels out into the sunshine. Or if you are setting your solar panel up for emergency lights there is a good chance you can set the panel far enough away from the house to catch some light.

The two florescent light cords are pretty long too - 16 feet per my measuring tape.

Step 6: Connecting the Battery and Lights

The final step is connecting the battery. I went ahead and connected to a marine battery I had laying around and before I turned the controller on I disconnected the solar panel just to see what the voltage was. It's pretty low - 9.8 volts but it's also a very discharged battery

Next I connected the solar panel back up and the battery reached 12.8 volts pretty fast. This is a good sign for the solar cells - they are producing power. But it looks like I'll be replacing this battery because the voltage should not have come up this fast!

Once I had charged the battery for about an hour I tried the lights. They seem to work well.

Step 7: Technical Stuff - for Anyone Who Cares

I chased down the schematic for the Harbor Freight charger and it's pretty impressive for what it is.

The charger uses a comparator circuit and a reference voltage to switch the solar cells on and off. This is important because you don't want to over charge your battery.

The charger uses a second comparator circuit and the same voltage reference to disconnect your loads when the battery gets too low. This is just as important because discharging your battery too much will destroy your battery.

Step 8: Conclusion

It seems to me that this kit would be a great addition to anyone's camping gear. You should be able to run lights and maybe a small exhaust fan inside your camper.

You could also set one up for emergency lighting in case of a power loss. This happened to us a few years ago in North Alabama and I was fortunate enough to have a couple of gas lamps to light up the house.

But this Harbor Freight kit has some limitations. You won't be able to run a A/C unit or small refrigerator or freezer. These appliances need a power source much larger than this kit will provide.

So, what do you need to run a "typical" freezer in an emergency?

Per my deep freeze data plate it need 5 Amps and 5 Amps X 120 Volts is 600 Watts. Run this freezer for an hour a day and it will consume 600 Watt/Hours of power. I'm quoting an hour because I discovered that, at least with my freezer, an hour a day was enough to keep my food frozen and safe.

Assuming the Harbor Freight kit charged at full power for 10 hours / day, and it won't unless you live someplace like Arizona, it will only charge 450 Watt/Hours of power a day. This is far short of what I would need to run my deep freeze an hour a day. Your situation would be a little different based on the freezer you own, regardless this kit won't work.

So, what do you really need to keep your frozen food frozen in an emergency? I figure about a 300 - 400 Watt solar panel, a charge controller rated for your solar panel's wattage and enough batteries to store that energy will do. A "off grid" solar panel kit from Home Depot will cost you about $1400 and you have not bought the batteries yet. A generator is cheaper.

I wrote this instructable as a review of Harbor Freight's kit, but the real reason I bought the kit was to install solar lighting in my storage building. You can see the full install in this instructable.