How To Connect A Solar Panel Bought At Harbor Freight To A Jackery Explorer Power Station
Solar panels can be bought at a lot of different places nowadays, the popular hardware store Harbor Freight is one of those places.
A Harbor Freight solar panel is not compatible with a Jackery power station directly out of the box though since it requires additional adapters.
Related Product: Extend the cable between the solar panel and the power station with an SAE extension cable by iGreely (click to view on Amazon)
In this article I am going to tell you what these connectors are called, and how you go about connecting the two.
What You Need To Know
Before we get into the specifics, there are some things we need to know before we connect anything.
Solar Charge Controller
The job of a solar charge controller is to take the voltage and amperage generated by a solar panel and regulate it. Then it sends the regulated electricity off to the battery.
Portable power stations have built-in solar charge controllers so you can connect solar panels directly to them.
The Jackery Explorer is not going to charge if you use two charge controllers. Therefore, we should not buy a solar panel that has an external solar charge controller.
If you have already bought a panel that included a solar charge controller, you can (hopefully) simply not use it. If it’s hardwired to the solar panel you’re going to have to either bypass it, or buy a different panel.
Input Ratings
Not all solar charge controllers are the same. They have different input ratings, meaning that they accept different voltages and amperages.
The input ratings can usually be found in the manual of the power station, or by the port on the power station.
Most Jackery Explorer power stations can handle voltages between 12-30V, and a typical 100W 12V solar panel like the most popular one from Harbor Freight outputs around 18V which makes it compatible.
If you combine two or more panels, you’re going to increase either the voltage or the amperage but we will get to that later on.
While it’s OK to exceed the amperage to a certain point, you should never exceed the max input voltage.
The Harbor Freight Solar Panels – What Connectors Do They Use?
Most solar panels sold by Harbor Freight today use SAE connectors. This is a two-conductor DC connector that is easy and quick to connect/disconnect, which makes it a great connector for a solar panel.
SAE connectors have one male pin and one female pin. One is positive and one is negative, but which is which depends on the wiring and adapters used.
The panels from Harbor Freight that use SAE connectors I have looked at have a positive female pin and a negative male pin. This is important when we search for the right adapter.
A positive wire is often red and a negative wire black. The wires are not different from one another other than the color, which is only made this way to make it easier to connect and follow the wire.
You might find a connector with a small “” or “-” on it, with a cable color that makes it look like it’s the opposite of what the connector says.
This is nothing to worry about, as long as you can follow the wire and make sure that the positive output ends up with a positive input.
The Jackery Explorer Input And The Adapter You Need
The input on Jackery Explorer power stations is called an 8mm connector. This is a round connector which also has a positive and a negative part to it.
Since we know that the SAE connector has a positive female pin and a negative male pin, we need an adapter that has the opposite.
This adapter includes what is called an SAE reverse polarity adapter, which will reverse the positive and negative. You do not need to use that to connect the panel to an Explorer power station.
Note that if you have the newer Explorer 1500 (click to view on Amazon), you are going to have to use the adapter included by Jackery to connect the adapter above to the power station.
That’s because Jackery has created a proprietary 8mm input for the Explorer 1500, and even though it’s called an 8mm input it’s slightly different from the regular 8mm connector used by other manufacturers.
When you have the adapter, you simply connect the solar panel to the adapter, then connect it to the power station.
Combining Two Or Panels To Increase The Charging Speed
It’s possible to combine two or more panels to charge the battery faster, but it’s not always worth doing so.
Since the charge controller in the power station decides how many watts it’s going to use to charge the battery, it’s good to know these limitations before spending money on more panels.
For example, the Explorer 160, 240, 300, and 500 max out at around 50-80 watts depending on model. The larger Explorer 1000 max out at 127W, and the even larger 1500 at 300W.
A 100W 12V solar panel will generate around 70-80W in sunny conditions.
It’s not always perfectly sunny though, and if you’re going to use the panels where it’s often cloudy it might be more worth it to buy an extra panel or two.
To combine two Harbor Freight panels for the Explorer power stations, you need an adapter like this by SolarEnz (click to view on Amazon).
This adapter also includes the SAE reverse polarity adapters, which you might need to ensure that positive goes to positive and negative to negative.
When you combine panels in parallel like this it’s very important that you have made sure that all wiring used can handle the amperage. That includes these adapters and extension cables.
Extension Cables
I recommend using SAE extension cables that come with caps to protect the connectors while not in use. These dust caps keep dirt, debris, and moisture out.
The thicker the cable the better, so look for the lowest gauge you can find and make sure it can handle the total amperage of your panel(s).
I like and recommend the iGreely SAE extension cables (click to view on Amazon). They come in different lengths and are compatible with the adapters I have linked to above.
While you can combine two shorter extension cables I suggest getting a long one instead. The more connections, the higher the voltage drop, which will decrease the total output to the power station.
Frequently Asked Questions
I’m not sure whether the polarity is correct or not!
You can use a multimeter to check the polarity of the wires. This is also helpful when troubleshooting a setup that’s not working correctly.
A digital multimeter like this one by Kaiweets (click to view on Amazon) works, just set it to four o’clock (20 by V DC) and stick the red test lead in the supposedly positive SAE connector on the panel/adapter.
Then do the same with the black test lead. If it shows a positive voltage on the little screen, you know it’s wired correctly. You can test it the opposite way to understand what it looks like if the polarity is reversed.
How long will it take to charge my Explorer power station?
It depends on how big the power station is in watt-hours. A 100W panel will generate around 70-80W, but if your power station has a max input of 65W you need to do a calculation based on that.
For example, the latest Explorer 500 (click to view on Amazon) has a battery capacity of 518Wh and maxes out at around 70W.
The way to calculate how long it would take to charge the Explorer 500 with a 100W solar panel is then: 518/70=7.4 hours.
We also need to consider the fact that the charge controller will start out charging the battery fast, then slow down as it is getting closer to a full charge.
Therefore, I would add another hour or two to the estimate to get a more accurate number, resulting in 8-9 hours for a full charge.
How much can I go over on the amps?
While I personally don’t recommend going over 150% of the maximum amps with an Explorer power station, Jackery do not recommend going over on the amps at all.
For warranty reasons you should stick to what the manufacturer says.
Some charge controllers are more sensitive than others, but I haven’t had any problems using 200W of solar with my Explorer 500 for a couple of years.
Are Harbor Freight solar panels waterproof?
The junction box on the back of the panel is water-resistant, and the SAE connectors should withstand rain as long as they’re connected to another SAE connector or has the cap on.
I would ask Harbor Freight to be sure though, since it might void your warranty if it’s damaged due to rain and/or dust.
Can I combine a Harbor Freight solar panel with a panel by different manufacturer?
You can, but I don’t recommend doing so. The reason for that is that the setup is going to limited by the voltage of the lowest-rated panel.
If you have two panels that are rated similarly you won’t lose much, but be aware of the limitations.
Please leave a comment down below if you have any questions or experience with this and have something to add.
by Jesse
Jesse has always had an interest in camping, technology, and the outdoors. Who knew that growing up in a small town in Sweden with endless forests and lakes would do that to you?
6 thoughts on “Connect A Harbor Freight Solar Panel To Jackery Explorer”
I can’t get the harbor freight 100 W solar panels to charge the Jacari 1000. I’ve use both the 8 mm and the two prong adapter but still does not register. Not sure what else to do. Reply
Hi, Do you have a multimeter so you can test the connections? It’s likely a loose connector or a polarity problem. Reply
Can I charge a Jackery Explorer 240 with a 100 watt solar panel from HF? The one I’m looking at is the THUNDERBOLT SOLAR 100 Watt. The Jackery 240 is sold with their 60w solar panel. Is it safe to connect the HF 100 to the J240? Reply
Hi, Yes, it’s compatible and will work great with the Explorer 240. You just need the SAE to 8mm adapter (click to view on Amazon). Looks like the polarity lines up correctly, so I don’t think you need to use the included SAE reverse polarity adapter. Reply
Pete’s Solar Energy Experiemnt
In November of 2007, I bought this kit and installed it on our south-facing deck so it gets sun all day, if there is any. I don’t have any firm plans for using this setup to produce useful power. It is purely an experiment to help me understand how much solar photovoltaic energy can be obtained at this exact spot in the world, Lat. 44.874 dN, Lon. 92.294 dW. For me, reading is good, but DOING is better. I have a daily log of this experiment on an Excel spreadsheet and a rather lengthy text of internet dialogue somewhere around here. I won’t bore you with it for now. What follows is a summary of what my testing setup is and what it does.
The Answers, so far: My first conclusion about all this: I suggest that we can expect about 1/3 of the rated power of this 45 watt solar collector for about 6 hours per day, at this place in the winter,or, about 100 watt-hours stored per day, if we have a pretty good (non MPPT)PV charge controller, on a sunny day.
My second conclusion: On a cloudy winter day, we can expect to store about 3 watts of solar energy for about 6 hours or about 18 Watt-Hours per day.
Observation 3: It appears that the solar collector peaks out for about 3 hours in the mid afternoon. Maybe I’d only need to adjust the collector tracking about once every 3 hours to get all I can. The same goes for seasonal adjustments. I changed the tilt by 7 degrees from optimal and saw NO difference in insolation. Maybe 3 or 4 tilt changes per year are enough.
Observation 4: (A refinement of Obs. 3), When the solar panel is within about 25 degrees of optimum, there’s no appreciable difference in output.
Observation 5: When the Harbor Frieght charge controller can deliver no current to the load, which happens for a while in the morning after the sun comes up, and for a while in the evening before the sun actually sets and the sky becomes totally dark, there IS NO CURRENT TO BE HAD, even if a sophisticated MPPT controller were to be used.
Current Situation
Here’s my setup (as of March 16, 2008). The only things missing from these picture is the car battery, which is in the basement, and a box holding some big rheostats that I now use to test the MPPT idea. I didn’t say it was going to be pretty!
Solar Panels: I can change the tilt by adding or subtracting 2 X 4’s and 4 X 4’s from under the back edge of the support. The panels are tied down to the concrete blocks with a piece of baler twine so they won’t blow over.
Data Acquisition Unit: This DAU has 4 analog channels and 2 digital channels. This model hooks up to a serial interface, but now they have a USB model, which I’d recommend, instead. It is connected to the controller interface with a piece of 4 conductor phone wire.
Controller, Controller Interface and Load Bank: Again, I didn’t say it was going to look pretty! This is about the fourth iteration. Maybe the twentieth? This controller is the third one I have had. I don’t think they can stand the stress of removing the collector input while the sun is out. This controller is a later model than the one in the picture at the top of the page. This is a pretty nice controller, but it is NOT a MPPT (Maximum Power Point Tracking) controller. The most notable difference between this model and the original is that this one has a digital volt meter on the front. It is connected directly to the battery terminals. Internally, the positive side of everything is common, not the negative side. That’s why I had to build my interface with the voltages going negative and the current going positive. The controller interface board is contained within the little black box in front of the controller. On the top you can see a switch that disconnects the the battery from the DAU, and, if you look closely, just behind the switch, you can see the 0.1 Ohm 1% power resistor that is in series with the collector panel to measure current flow. In front of the controller on the little table sits the Load Bank. It consists of 4 16 Ohm 75 Watt wirewound resistors that can be connected to the little black box in front of them in almost any configuration your little heart desires, from 4 Ohms to 64 Ohms. The switch on that black box allows me to turn the load on and off without having to pull plugs out of the box. I almost always use 8 Ohms, for now. This gives the setup a power dissipation of about 21 Watts at normal panel output voltage when current is flowing. Finally, just to bug serious-minded folks, are the electrical schematic and the little interface PCB layout, almost readable.
Maximum Power Point Tracking Tests: I don’t intend to add an MPPT controller to this little system, but I do want to know how much more power I could be getting if I had one. So, I will change my setup so I can switch my charge controller in and out and replace it with some power rheostats. Then I can sit in front of the computer as it monitors panel voltage and current, changing the load resistance to see where the maximum power point is for any particular solar drive voltage compared to a similar power (wattage)output using the HF controller. As of March 15, 2008, I have stuck 4 rheostats in a box and added them to the overall system. They are: 25 Ohms, 100 Ohms and 250 Ohms, all on a common frame, and 35 Ohms all by itself. The reason for this combination is that 1.)I know from developing the load bank mentioned above what the approximate range should be, and, 2.)Those were some rheostats that were available at a surplus electronics place on the web. This box is hooked in parallel with the panel input and controlled with an SPST switch. To use it, I simply turn off the switch on the front panel of the HF charge controller and turn on the switch to the rheostat box. This next image shows the overall wiring of the system at present. The image after that shows the voltage divider PCboard that goes between the charge controller and the DAU (because I couldn’t get my CAD program, Turbocad Pro, V7,to save with enough resolution).
Schematic of Interface PC Board Between Controller and DAU
What’s Happening Now: The Harbor Frieght panels are hooked up and operating. I’m on the third charge controller now and it has a slight problem in that the controller locks the panel to the battery whenever the panel voltage DROPS to the battery voltage. The only problem for me is that I don’t get to see the panel voltage drop as the sun goes down unless I turn the controller off, allow the panels to go to open ckt voltage, and then turn the controller on again.
I record 3 channels of information each day with the DAU (Data Acquistion Unit) hooked between my PC and the solar PV (PhotoVoltaic) system. The software that came with my 25 Dataq DAU allows me to graph the data that I store, albeit in a limited manner. I can port the data to Excel where I can rework it but, I just haven’t gotten aroundtoit yet. The DAU requires signals between zero volts and 10 volts. The inputs are not isolated from eachother. So, I had to design an interface between the solar system and the DAU. It is currently a passive voltage division and series current sensing system. To keep wasted current to a minimum, the current sensing channel is running on a voltage so low that the DAU is non linear in that region, but never worse than within 15% or so. That design is good enough for now. Lastly, in defense of DATAQ, I bought this DAU as an entry level device in 2003 and never even took it out of the box. For the 25 it cost me, it is a great tool. They still have it, in the serial verson for about 25 and in the USB version for 50. REAL ones start at about 200, and they include better software.
Data Recording
Just today, I put a few images of of my recorded data here. The graphs, a set of 3 traces for each of the 6 days presented, are from some of the sunnier days in January of 2008:
Here are some particulars of each Set of 3 Traces:
Upper Trace: Photovoltaic Panel voltage output, negative-going. Multiply the value by 10 to get DC volts. eg: 1.36 = 13.6 volts.
Middle Trace: Actual current being drawn from the collector panel. This is a positive-going signal. Multply the graph reading by 8.5 to get actual current in DC amperes. (Think 10 to make it easier)
Lower Trace: Battery voltage, negative-going. Multiply the value by 10 to get DC volts
You can generally see that the collector panel voltage rises as the sun comes up, but no appreciable current is generated until the sun gets well up into the sky (if it’s not a cloudy day). Later, the current falls to zero, but the collector is still forward biased, producing the voltage you see for a couple of hours. Then, of course, clouds during the day cause to current to fluctuate. The Charge Controller has a feature which shuts off charging when it thinks the battery is full. You see that function when the current drops suddenly to zero and the collector panel voltage climbs to it’s full no-load open curcuit value (as high as about 23 volts DC, if the scale was set that high).
Graphs
Here are 6 graph sets, if you are interested. Don’t feel bad if they don’t make full sense to you. The DAU I am using is somewhat simple-minded as is it’s software. (IT WAS cheap!) I had to do some work-arounds to get it to do some of the things I wanted.
Again, here’s how the graphs work: At the left of the charts you see the channel numbers, (1=1, 2=2 and 3=3). Just to the right of each channel number is the chart’s title. Above and below that are the limits for that channel graph.
1=1 is the Collector Voltage graph. The limits on the chart.000 and.2.000, mean that the voltage is zero at the top of the chart and.20 volts at the bottom of the 1=1 trace area. The X10C simply means that you multiply the reading by 10 to get the actual Collector voltage. (The number.013 just above X10C is the reading that was at the black vertical bar that’s about 4 squares in from the left.)
2=2 is the Collector Current graph. The limits on the chart.000 and.500 mean that no current is flowing from the collector panel at.000 and, at.500 you’d multiply by about 8.5 to get the actual current in amperes. Sorry about this, but that’s the non-linearity of the DAU that I mentioned earlier. The X10A implies multiply by 10 and that’s good enough for you to get a general idea of what’s actually going on. I use an amperage correction table that keeps my actuals to about 2%.
3=3 is the Battery Voltage graph. Same everything as 1=1.
December, 2008 Now that I have a whole year of data, I conclude that, if you are already connected to the grid, then solar photovoltaic energy collection and storage is not for you. Maybe, if and when the price of the equipment drops by a factor of about 4 and/or the cost of your electricity doubles, take another look.