Why Do We Want to Bypass the Solar Charge Controller?
When I was looking for third-party solar panels to go with my Goal Zero Yeti 1000, I found the Renogy 100 Watt Suitcase solar panels. It’s two 50 watt panels connected that folds and stores easily in an included bag. They’re a great option when you want portability and not a permanent solar install.
The Renogy 100W Suitcase is sold both with and without a charge controller. I bought one of each. The charge controller included is the Renogy Voyager, a 12V controller that can handle up to 20A.
So why did I buy one with and one without? Because I wanted to be able to use both panels with my Yeti 1000 but also my 12V RV battery. The panels come with alligator clips, ready for a quick connection to an RV battery. To connect them to a Yeti power station, however, we want to bypass the solar charge controller since there is already a controller built into the Yeti.
This is what I ended up doing (click here for a larger picture)
In the picture above, it’s ready to be connected to a 12V RV battery. Note that in the image above I have also cut the alligator clips shorter to be able to make an extension cable out of the alligator cable.
When I want to connect it to my Yeti 1000, it looks like in the next picture below (except I use an extra extension cable in between to reach the Yeti).
How To Bypass The Solar Charge Controller
The main thing I have done as seen in the pictures above is to add MC4 connectors between the conjunction box on the left solar panel and the charge controller. By doing so, I can easily connect and disconnect the panels from the charge controller.
Here is what you’ll need:
- MC4 Connectors – I bought Renogy MC4 connectors, a pack of 5 pairs.
- MC4 Crimping Tool – I just used a pair of pliers instead of this tool, but the tool makes it much easier.
- Wire Stripper – To strip the wire so we can install the MC4 connectors.
- Renogy MC4 Tool – This is a tool used to assemble and disassemble MC4 connectors.
- Box cutter/Pocket knife – To remove the protection on the cables before we strip them.
Before we get started, I want you to understand how the panels are set up with the charge controller when it’s shipped by Renogy. It is as follows:
- The right solar panel is connected with one cable to the left panel. This wire has both a positive and a negative. It goes into the conjunction box. We’re not going to mess with this wire at all.
- In the conjunction box, the left panel and the right panel are connected in parallel.
- One cable comes out of the conjunction box and goes into the solar charge controller. Note that the positive (red) wire goes into the + connection on the charge controller input with a picture of a solar panel. The negative (black) cable goes into the – input.
- From the solar charge controller, a cable with two MC4 connectors on the end, come out. As with the solar cord, the positive is red, and the black is negative.
- These MC4 connectors can then be connected to the included alligator clips. They only fit one way, but always make sure you connect positive to positive and negative to negative.
Now that we know how it’s all connected before we mess with it, let’s get started.
- One quick way to do this would be to cut the current wire between the solar panel and the charge controller, then install MC4 connectors. However, I felt like there weren’t enough cable between the panel and the controller to where I could do this without putting a lot of strain on the cable each time I connected/disconnected it. So what I did is that I removed both connections going into the solar charge controller first. To do this, lift the weather protection piece and unscrew the screw on the back until the cables can be pulled out.
2. Then I cut the cable I removed coming out of the charge controller with MC4 connectors on the end. I cut off about 7 inches.
3. Now we have to get access to the positive and negative wire on the cables we just split. I used a box cutter, but you can also use a knife or a razor blade. This is pretty tricky since you have to be really careful and not cut into the red or black little wire. Slowly work your way around, cutting into the thick outer protection on the wire, about two inches onto the cable. I bent the protection while cutting to make it easier. In the picture below, I cut it twice to make it easier to understand what I am talking about.
4. After you have cut both wires we cut earlier you should have one with wires coming out on both sides, and one with wires on one side with MC4 connectors on the other.
5. Now we need to install MC4 connectors on one end of the cable that has wires coming out of both ends, and the solar panel wire we disconnected from the charge controller. Installing MC4 connectors is an easy process, as seen in the video made by Renogy below. Watch the whole video, and then we’ll go over which connector goes where.
6. Since we’re going to make an MC4 connection between the solar panel and charge controller, we must put a male part on the positive (red) cable coming out of the conjunction box, and a female part on the negative (black) wire. As seen in the picture below. Remove the protection, strip the wire (16 gauge) with the wire stripper, and install the MC4 connectors.
7. The short cable with wires coming out of both sides is going to make a connection with the cable seen above, so we need to put a female connector on the positive (red) wire, and a male connector on the negative (black) wire.
8. When that is done, you should be able to connect the positive (red) MC4 connector from the solar panel to the positive (red) MC4 connector on the short wire. This wire can now be screwed back into the charge controller. + is positive (red), – is negative (black).
9. If you removed the black protection from the longer cable you cut in step 2, you can go ahead and use the wire stripper (16 gauge) to remove about an inch from the positive and negative wire to expose the wires. If you haven’t removed the protection yet, do so before stripping the wire.
10. Now connect the cable with MC4 connectors on the other end to the side of the charge controller with a small battery on it. Connect the positive (red) wire to the +, and the negative (black) wire to the -.
It should look like in the picture below when you are done. The little rubber piece protecting the connectors can be put back on by wiring the wires through it.
11. Done! Now you can decide whether you want to connect the MC4 connector coming out of the solar panels to your Yeti with an adapter, or if you want to keep the solar panels connected with the charge controller, and then the alligator clips to your 12V battery.
As mentioned earlier, I also cut the alligator clips off and put MC4 connectors on each, then put MC4 connectors where I cut it, to make an extension cable I can use to connect two 100W panels.
You can connect two panels to your Yeti or charge controller by using a MC4 Connectors Y Branch Parallel Adapter. The way you use it is that you connect the positives, and the negatives together separate, then you connect them to the adapter for the Yeti, or into the connector we made to the charge controller. Note that if you’re using a Goal Zero Yeti, you must bypass the solar charge controller since the Yeti already has one built-in.
I’m not the best at describing how to do things, so please leave a comment if you have any questions and I will do my best to help you. There might be better ways to do what I accomplished above, but it worked for me and didn’t take too much work.