Wednesday, July 22, 2009

Harbor Freight 45 Watt Solar Panel Kit


I wanted to do a post on one of the most popular subjects in the alternative energy arena....The Harbor Freight 45 Watt Solar Panel Kit. It only makes sense that this kit gets so much attention, it's inexpensive!

Let's face it, the majority of people interested in solar energy and living off the grid are beginners and this kit makes for a great place to start in your adventure into learning about solar power and living off the grid.

This blog does not get a lot of people sharing comments. A lot of readers, but few people leaving comments. I want to change that with this post, please feel free to use this post as a virtual forum on the Harbor Freight 45 Watt Solar Panel Kit. No matter what your skill level or experience is in creating solar power please share all of your knowledge of the pros and cons of this system. And ask those questions no matter how simple or complicated they may seem.

I found a lot of information out there and most of it ended with "the charge controller sucks". Let's continue that conversation here, but does somebody have any recommendations on a good charge controller that is a good replacement? Please list some links even if it is to your own site, we want to know!

If you are not familiar with the system here is one of the most popular solar energy videos on You Tube from Dan Rojas at Green Power Science. Dan produces great videos for the beginner and you should really take the time to watch all of his videos on You Tube.

26 comments:

Paul G. said...

My toe is in the water.
I purchased this lit yesterday, tested it today.
I was hoping to find comments just like you are asking for concerning charge controllers.
I'm also curious about what battery and inverter combinations people have chosen and why.

Renewable Ray said...

Thanks for starting the conversation Paul. Hopefully we can get some current owners of the kit involved. Obviously your first addition/upgrade will be a pure sine wave inverter. You don't even want to attempt to use this system as it is with any electronics. It should work great for small power tools etc.

Anonymous said...

I have 3 of these kits, two with the old style controller, and one with the new style (with the digital meter on it).

The controllers I only use for running lights and stuff, not as a charge controller. I bought a Sunforce 30 amp controller at Northern Tool for charging.

They are great kits for learning about solar with.

I have recently bought a 80 watt Sharp panel to upgrade with.

Renewable Ray said...

Who did you buy your 80 watt Sharp from?

Anonymous said...

Northern Tool. I have both a Harbor Freight and a Northern Tool nearby. I think the 80 watt panel was $549.

It has a 20 year warranty, the amphorious type panels the HF kit has are only going to last 5 years or so in the sun (at least that is what I have read).

Renewable Ray said...

Found a lot of people having problems with adding additional length to the leads from the panels to the controller since they are only 10-12 feet long. here is some great info I found from Marshall at All Experts.....

Question
Hi Marshall - I recently bought a 45 watt solar panel system (harbor freight) that is actually working fairly well. My problem is that the wire leads from the panel to the regulator are only 11’ long. There’s 3 leads (2 wires from each panel + & -) and they appear to be about 18 - 22 ga. Can I extend these leads to maybe 24’ & what type & ga wire should I use for the extension. I plan to leave the original leads & use a terminal block and then run one wire each (+ & -) to the regulator. Thanks greatly for any help, ideas, & advice…..Mark

Answer
Hello Mark,

A quick look on the internet and I found a 45 watt solar power kit from Harbor Freight. The description stated: " Maximum current, 3000 mA. 15 watts max per panel. Peak voltage: 23.57 volts open current". There is a box shown in the photo which I am going to assume is what you are calling the regulator and that is can change the output voltage to 3, 6, 9, 12 volt DC. 23.57 open circuit voltage is important due to anything that is hooked up to the solar panel (not the regulator), needs to be able to handle this potential voltage or may be damaged. This is not the max power voltage (voltage under a work load). The max power voltage may be listed on the panel or can be guesstimated by dividing 15 watts by 3000mA or 3 amps equaling 5 volts. If wired in series, which they are, they will produce 15 volts with is common for a 12 volt system (wiring in series change the voltage and wiring in parallel changes the amperage). The thing with solar panels is that they grow and fall in intensity as the sun shines on or is blocked from the panel, so the odds are pretty slim that 15 volts will ever be constantly outputted. Temperature also effects the voltage output, the cooler the panel, the higher the voltage.

For wire sizing you start with the possible max amps (3amps) and find a conductor that can handle that load. A 22 gauge wire is sufficient for 5 amps, but there is also the issue of resistance in the wire can drop your voltage. This is the voltage drop. At the bottom of the following web page, you can figure out the voltage drop and the resulting voltage delivered to the work load.

http://www.powerstream.com/Wire_Size.htm

So a 22 gauge wire; at 12 volts, at a distance of 24 ft, at a 3 amp current will result in a 20% loss of voltage resulting in a delivered voltage of 9.6 V. 15 volts * 80% = 12 volts.


a 18 gauge wire; at 12 volts, at a distance of 24 ft, at a 3 amp current will result in a 8% loss of voltage resulting in a delivered voltage of 11.1 V. 15 volts * 92% = 13.8 volts.

If you wanted to charge a 12 volt battery, you would want to deliver 14 v. In solar electric design, the lowest voltage drop we allow is 2% which means I would recommend a 12 gauge wire for a 24 foot run.

As far as what wire type, if it is in an NEC approved conduit, then I would recommend THHN-2. If it is going to be outdoors exposed I would recommend USE-2. You will probably need to find USE-2 on the web as most hardware stores and electrical parts houses don't carry it in-house.

Good Luck
Marshall

Anonymous said...

I have this kit. I was something I wanted for a while. I like the videos Dan Rohas has I think he deserves TV show like bill nie the science guy or something. I would watch.

Anyways the kit. I have it with three watt panels connected also. It made the difference the extra panels. I know another 15 watts no big deal but, in my opinion there is not much juice of this kit. But, I do suggest it. I got a 2X1 board cut to inner length of rear or the triangles and bolted in. Helped alot with moving it around.

I want two of these on a solar tracking unit. Any help out there...

Renewable Ray said...

If you are seriously thinking of buying a one [or more] of these kits take advantage of this 20% off coupon. It's only good for this weekend, but you can get these emailed to you on a regular basis if you just sign up with them. Our local Harbor Freight stores have these kits marked at $249.00 but the real regular price is $199.00. With the coupon you can knock that down to $159.99, worth the signing don't you think?

Renewable Ray said...

here is the link to the latest coupon.

http://www.harborfreight.com/hftusa/magpromos/popsci.pdf

Anonymous said...

After eyeing the kit at Harbor Freight for a while, I just bought one yesterday. I probably won't install it until Spring, but I unpacked it and played with it anyway...The mount/stand was fairly flimsy upon assembly, so I threw a few tack welds on key points. I too have heard that the controller is low-quality, and it's a shame because it has such nice features like variable voltage (3,6,9,12) and a USB port. I'll try to stop back for more details as time goes on.

Renewable Ray said...

Remember, a lot of the negative comments you are reading about the controller are refering to the old controller. They have upgraded this and I have not heard of any real serious problems with the new version. Would love to hear them.

Anonymous said...

I bought the Harbor Freight 45Watt solar kit last year for $150 +/-, and made a custome frame to hold them on the roof of my van. Use them to run lights (supplied with kit) and a 100 Watt amateur radio, plus alternate power for charging vehicle battery if needed. Totally happy with kit. Got two deep cycle batteries from hospital surplus that were used for radiation equipment. The foot print of the two batteries is same as typical automotive battery, so if they die...I'll replace with one single battery. 7-8 months in use...they work great. The controller with multiple outlets and two plug in bulbs are nice. If I had place to use more of these...I would not hesitate to buy more, especially at $150/kit!

dexter said...

Can somebody help me in building up a solar power generator?

Your comments are much appreciated.Thank you.

http://www.sunpowerport.com

Renewable Ray said...

Just wanted to let everyone know that we have added a complete forum just for the Harbor Freight system. It's turning into a pretty active site for just starting out.

Check it out > http://solarpanelkitatharborfreight.ning.com/

Anonymous said...

I also ordered the 45 watt solar system. I have had it up now for a while now with not very good results. I bought 2 deep cell 65ah batteries and this system will not charge them past 34% or 11.9v. I don't know if the batteries i got are bad or the system is not big enough to charge them to 100%. I bought 3 50w panels and will be putting them up along with a 650w wind turbine.

Renewable Ray said...

What kind of levels did you start with on those batteries? If you are not using any of the power these panels should be able to charge them. Sounds like a battery problem. Are they used?

Anonymous said...

I am looking at purchasing this kit... I am a complete novice w/ no electrical education... my question is what type of appliance or equipment will this kit run? I am thinking of using it as a power back up for emergencies. Will it power a dorm frig, a household box or stand type fan and would they have to be run one at a time?

Anonymous said...

Not sure if my kit is bad but my system only reads 14.3 max in full sunlight here in sunny california. This is at 3:00pm. The low voltage light constantly blinks as well.

Anonymous said...

We are thinking about purchasing this kit for camping, we go to primitive out-of-the way places and would like to be able to run a 20 inch box fan, etc. What type of appliances can you run off of this system? Any info would appreciated.

New World Solar said...

Everything you could possibly want to know about this kit can be found at this forum http://solarpanelkitatharborfreight.ning.com/

Great bunch of folks.

Bruce M said...

I just bought 1 of these last night, It was listed on Harbor Freight website for $169.99 then I had a 20% off coupon, It ended up costing me $146.00 out the door, I was thinking about going and buying another one. I'm new to Solar but I have seen seem at Harbor freight several times and did some reading on them so I thought what the heck. We have been haveing a LOT of power outages lately so I thought I would give one a try. They go off sell today the 24th at close

Cassie said...

I'm a newbie on these kinds of solar panels, and was looking for peeps who can share their experiences and ideas/thoughts about it.. By the way, thanks for linking a video about it..

zonnepanelen

Anonymous said...

I just bought one of these sets two weeks ago. The panel structure stinks in my opine. I squared mine up and welded up the frame. I'll then mount that to a piece of plywood.
Seems like a decent unit. I use it to charge several 12 volt car batteries at my camp that I use for accessory power. This way I keep the generator running to a minimum.
So far so good.

Solar Panels said...

To build your own panels, knowledge about the different solar cells is a requisite.


Solar Hot Water

Nick said...

I just got into the solar "game," and your insights and videos have been a HUGE help! Thanks! I just installed the HB 45 watt kit in my VW Vanagon. Panels on top running to the HB charge controller, running to a 12V deep cycle. I have the charge controller and the battery butted up to one another inside of a bench storage compartment. I have 2 questions: Is that a fire hazard? and Do I need to be concerned with fumes?

Renewable Ray said...

Hey Nick, as far as fire hazard just make sure the batteries are secured just like you would if they were under the hood and yes you need to be concerned about fumes. Not enough people take this serious enough in vehicles or their home units. The box needs to be sealed and vented. Make sure to visit our forum that is dedicated to the Harbor Freight Kit at http://solarpanelkitatharborfreight.ning.com/