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.
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8 comments:
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.
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.
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.
Who did you buy your 80 watt Sharp from?
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).
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
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...
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?
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