Solar panel from Harbor Freight

[GeocamperAS]

Has anyone used the 45 watt solar panel kit from Harbor Freight? Pros and cons?

[idroba]

Basically they are a toy. I got one to play with. The panels are reasonably well made but the output is small, only 15 watts per panel and they are the kind which has a low output per unit area.

For $140, shipped to your home, you can buy a good 100 watt panel from Grape Solar, via Costco. A much better deal overall.

Grape Solar 100 Watt Polycrystalline PV Solar Panel

[Phoenix]

Just curious, has anyone done a DIY installation of the Costco/Grape Solar panels?

Would appreciate details and photos...

[HowieE]

Originally Posted by idroba

Basically they are a toy. I got one to play with. The panels are reasonably well made but the output is small, only 15 watts per panel and they are the kind which has a low output per unit area.

For $140, shipped to your home, you can buy a good 100 watt panel from Grape Solar, via Costco. A much better deal overall.

Grape Solar 100 Watt Polycrystalline PV Solar Panel

What controller and other parts did you have to add to the $140 to complete the install?

[TinShack]

Originally Posted by GeocamperAS

Has anyone used the 45 watt solar panel kit from Harbor Freight? Pros and cons?

I used a kit similar to this for about 2 years. They will work and charge your batteries but they are not the best choice. They are amorphous panels so are only about 5-6% efficient compared to about 11-22% efficiency for mono-crystalline panels and about 8-15% for poly-crystalline. The sun produces about 1,000 Watts per square meter during the hottest part of a summer day in North America. Efficiency tells you how much of that solar energy will be converted into electricity.

They are also heavy for the amount of output. The shipping weight is about 50 lbs. If you are planning to use them for your trailer, keep in mind you will have to carry that weight around and set them up. It gets old. The cost per watt is about $4.44.

If you want to stick with a portable solar kit similar to this you can build your own using a panel or panels like the Grape Solar mentioned above. You will need a controller, cables, and a stand as well so keep that in mind.

Another option is this kit or similar... Go Power! GP-PSK-120 120W Portable Folding Solar Kit. The 120 watt kit includes hinged panels. controller, cables, aluminum stand and carry case. More money but almost 3 times the power and a lot less weight. Cost per watt is about $4.52.

[idroba]

Originally Posted by HowieE

What controller and other parts did you have to add to the $140 to complete the install?

I put two of the Grape 100 watt panels on my 2014 FC 20. I used a Blue Sky SB2512iX MPPT charge controller, which was about $200. I built my own mounting system, but now I would use the one that Lewster uses with hi bond mounting tape. I used the factory installed solar pre wire (#10) which is fine up to the 200 watts of panel I have. My total cost was under $700, and the panels were $160 when I bought them.

I think I posted photos of the panels on the trailer in the thread called something like "show your solar panels" which should show up with a search.

I had put a Tri Metric meter on my system already and find it handy for monitoring my batteries. In the spring I plan to convert the two existing group 24 batteries to two golf cart 6 volt batteries in series, again for additional capacity.

[gmw photos]

I have the "even more of a toy" harbor freight 15watt panel. It folds in two to about the size of a briefcase. I've had some fun with it, and actually managed to keep a battery mostly up for a week of boondocking at the ballonfiesta. at the time, I did not realize my refrigerator has a heating coil in the door gasket, and that was a constant drain that I suspect was part of my problem that was sucking power.
Still the little panel kinda sorta worked, but I found I really had to stay after it and keep it as directly aimed at the sun as I could, which meant going over and moving it every hour or so. It was a fun little experiment, but I am not one that does serious boondocking, so I pretty much set it aside.

If I am ever going to use it again, I will disable the heater strip in the fridge gasket to give this panal a fighting chance.

Most of of the stuff from Hazard Fraught is pretty much short term junk. Hey, I still go in there for a few things ... !

[Joe Palmieri]

I purchased the 45 watt solar panel kit from HF several years ago for my SOB white box trailer. They did help keep my batteries charged but I had to monitor battery consumption and limit use. They became a PITA to put up and take down each trip. "Miss Piggy" has 160 watts of solar on the roof that do not require any work and do a much better job. The 45 watt system from HF is now mounted on a stick pointing South on the roof of my garage and is now being used as a battery tender for the batteries in the garage. The controller is mounted on the rear inside wall and I have a 50' #12-2 wire with a plug that can reach all the batteries in the garage. The system still functions perfectly after six years for this type of use. A higher wattage solar panel system on the roof of a travel trailer is money well spent. The higher wattage the better.

[Al and Missy]

I just found the Grape panel at Home Depot Online. It's $10 more at $149, but also has free shipping, if Costco isn't convenient. HD has 5 pages of solar stuff, who knew? They have an inexpensive charge controller as well. Just be sure to get a three stage controller.

Al

[idroba]

Good to know that Home Depot has the Grape Solar panels at reasonable prices and free shipping. Shipping costs can kill you when ordering panels online.

In looking over the HD selection of stuff, I am not sure why there is a 105 watt panel for $160, it looks to be the same size etc. Seems strange. The 160 watt panel they show would also be a good candidate for Airstream Solar if you have space for it. The higher wattage panels they show would need a special charge controller if used with 12 volt systems.

They have a "kit" of a 100 watt panel and a Xantrex charge controller for $350 which does not seem like a good deal to me. The Xantrex charge controller is a good one, but available in other places for about $100. Along with a $150 panel, that is only about $250 so why is it priced at $350?

They show a Coleman charge controller for $97. The price is ok, but I know little about the product. I would use a Xantrex for the same money. I have a lot of experience with Xantrex controllers and have never had an issue in the past 10 years. If you were looking for the most modern technology in controllers, the Blue Sky MPPT controllers are good ones in the $200 range (not from Home Depot).

[drboyd]

Not to butt in, but there's a Renogy 100 Watt solar panel (from Amazon of all places) that gets good reviews for $149.99 with free shipping. I'm gonna try one out on an angle stand with an Eco-worthy mppt controller. I'll letcha all know how it does.

If it actually turns out to work, I'll try to get one or two more and mount them on the roof.


Edit: Hooray for me! It's my 500th post, and now I'm an Official Rivet Master!

[TinShack]

Originally Posted by drboyd

Not to butt in, but there's a Renogy 100 Watt solar panel (from Amazon of all places) that gets good reviews for $149.99 with free shipping. I'm gonna try one out on an angle stand with an Eco-worthy mppt controller. I'll letcha all know how it does.

If it actually turns out to work, I'll try to get one or two more and mount them on the roof.


Edit: Hooray for me! It's my 500th post, and now I'm an Official Rivet Master!

Congrats on reaching posting Nirvana, Master! Thanks also for sharing the info on the great price for a monocrystalline panel. Post pics of your set up when it's done! What are you going to use for cable? Saw a friends homemade portable setup last weekend and he had two 100 w panels connected with a piano hinge. When folded, the space between allowed him to store the cables and controller to make a nice neat package. He used 8 gauge low voltage lighting wire for his cables.

[drboyd]

Well, I'm planning to approach this in two stages. The first stage will just be this single panel and charge controller on a cable long enough to let me park the trailer in the shade but keep the panel in the sun. Probably be a couple of legs on it for some tilt, and the charge controller mounted on a piece of aluminum stock across the back.

The cables from the charge controller will either (a) attach to a couple of MC4 tee connectors at the (single, so far) battery, or they'll feed in via the +12V and ground connections on a female 7 way trailer connector. I've already got the trailer connector, so I may lazy out and do that.

Eventually (given that this works) the plan is to have two panels on the roof and use the same charge controller.

How does everyone feed the cables down from the roof to the battery box? I saw a picture of a refrigerator vent adapter.... I was thinking I could run the two cables down the refrigerator vent, then out the bottom of the refrigerator compartment. From there, I could cable-tie to the refrigerator propane line which runs to the front right under the battery box.

But - I *am* real interested in how everyone else has done it.

And a big THANKS! That low voltage lighting cable is an awesome idea! I might just have some of that lurking around out in the garage.

Oh - and fuses! One between the panel and controller and another between the controller and the battery.

Originally Posted by CA Streamer

Congrats on reaching posting Nirvana, Master! Thanks also for sharing the info on the great price for a monocrystalline panel. Post pics of your set up when it's done! What are you going to use for cable? Saw a friends homemade portable setup last weekend and he had two 100 w panels connected with a piano hinge. When folded, the space between allowed him to store the cables and controller to make a nice neat package. He used 8 gauge low voltage lighting wire for his cables.

[idroba]

Oh - and fuses! One between the panel and controller and another between the controller and the battery.

The fuse between the panels and the charge controller is not absolutely necessary, as the panel output (unlike a battery) is self limiting by the panel capacity and sunshine and the battery does not back feed through the controller. A fuse between the battery and charge controller is correct though.

[drboyd]

What happens to the panel if the output is dead shorted? I can't imagine that it would do the panel any good...

Originally Posted by idroba

<snip>

The fuse between the panels and the charge controller is not absolutely necessary, as the panel output (unlike a battery) is self limiting by the panel capacity and sunshine and the battery does not back feed through the controller. A fuse between the battery and charge controller is correct though.

[idroba]

A dead short on a panel is not at all harmful to the panel. It is a common way to test panel output both at the factory and in the field. Again, current does not rise above rated output on a dead short situation, unlike a storage battery.

In essence when the panel is charging a battery at full rated panel output the panel sees the battery in the same way it would a dead short.

[drboyd]

I would not have guessed that - so I definitely learned something today!

Thanks!!

Originally Posted by idroba

A dead short on a panel is not at all harmful to the panel. It is a common way to test panel output both at the factory and in the field. Again, current does not rise above rated output on a dead short situation, unlike a storage battery.

In essence when the panel is charging a battery at full rated panel output the panel sees the battery in the same way it would a dead short.

[idroba]

I should back off slightly on my statement. A single panel or a string of panels can be shorted with no issues, but when a set of panels or strings is put together, each string should be fused or breakered so a fault on one does not take the total current of the other strings. In larger many paneled systems, that function is done in a combiner box.

The energy in the shorted panel is simply dissipated over the surface of the panel which would get no hotter than it would not producing any power at all.

[drboyd]

Originally Posted by idroba

I should back off slightly on my statement. A single panel or a string of panels can be shorted with no issues, but when a set of panels or strings is put together, each string should be fused or breakered so a fault on one does not take the total current of the other strings. In larger many paneled systems, that function is done in a combiner box.

The energy in the shorted panel is simply dissipated over the surface of the panel which would get no hotter than it would not producing any power at all.

So an open circuit or a short circuit - neither one will damage the panel? Huh!!