In this update to our DIY Solar Generator how-to series, I am going to show you how to build an acrylic Plexiglass cover for the inside of the solar generator, so that we can store things like jumper cables inside the case without worry about shorting out or damaging any of our wiring connections. I will also show you some updates and improvements that I have made since the original videos, including a way to automatically disconnect the solar charger from the battery when the solar panels are unplugged. This will keep the solar charger from slowly running down the battery while in storage, without having to remember to turn on or off a disconnect switch. I will also show you a better solution I have found for the solar cable wire including heavier gauge cable, for less cost, and a built in cord wrap.
Plexiglass / Acrylic Cover
For the Plexiglass cover, if you have been following along with this build series, you can download the cut diagram below that I have made. It should work for you if you have mounted your components in the same positions I did. If not, you can create your own template using some cardboard. I will do another video to show you how to create cardboard templates.
Once you have your cut diagram, we can start cutting out the individual panels. The quickest and easiest way is to score the Plexiglass using either a Plexiglass knife, or a sharp utility knife. Once you have measured where you need to cut, use a straight edge to guide the knife and score the panel. Score it several times to help you get a clean break.
Then place the scored line along a sharp corner, and evenly flex the panel until it snaps along the score line. Use this same process for all of the panel in the cut diagram.
The two panels with an inside corner require a couple of extra steps. First we will drill a small hole at the inside corner. This is to keep the panel from breaking further than that point. When drilling Plexiglass, you will want to use the drill in reverse at high speed. The friction of the drill bit actually melts its way through, which keeps you from chipping and cracking the panel.
Then to assist the break in starting exactly where we want it, notch the two scored lines about an inch in from each end. You can use a vibrating multi-purpose saw like I am using here, or instead a fine tooth jigsaw or a Dremel type cutoff wheel.
At this point we will put the longest edge against our corner, and gently flex the panel until both scored edges break clean.
After you have all the panels cut, we will assemble them using acrylic solvent cement. I will use a water-thin fast set solvent (#4) initially, and then follow that up later with a thicker #16 cement to strengthen the joints. You can find links to where I purchased both of these in the description and in my linked blog post. I also purchased both of the applicators I used from Amazon as well. I will post those links below as well.
Lay the pieces on cardboard to soak up any excess solvent as you work. The solvent has a set time of about two minutes, so once applied you can make small adjustments. The joint will not reach full strength for 24 hours, so even after it is set, you still need to be careful at first.
Keep adding panels, referencing the cut diagram for their placement. You can use the existing panels you have already glued as alignment guides, so that everything matches together nicely.
After you have all the panels together, let it rest for several hours to gain strength. Then use the #16 solvent, which is much thicker, to strengthen the corners and fill any small gaps.
Improvements to Solar Cable and Connector
Previously I had recommended using high quality heavy gauge speaker wire for the solar cable, because it came with two wires bundled together, and was much less expensive than the photo-voltaic wire, which is not very flexible for coiling long lengths. Since then I discovered that you can purchase outdoor rated extension cords with 12-gauge wire for even less than the speaker wire, and not only is it more durable and weather resistant, the wire is much more flexible and great for coiling longer lengths.
You will want to snip both ends of your cord, and then carefully use a sharp knife to remove the outer insulation sheath. You can also trim off the green ground wire since we only need two conductors.
We need to connect these to the MC solar panel connector pigtails on the solar panel side. Make sure to connect the MC connector pigtails included with our solar kit to the solar panel, and make sure the solar panel wire with the negative (-) label is connected to our black wire in the extension cord. The white extension cord wire will be connected to the solar panel wire that is labeled positive with the plus (+) sign.
Then wrap the end of the extension cable with some electric tape for additional strain relief. I used heat shrink butt splices here for the wires, but if you did not, you could also wrap them too for weather proofing as well.
On the solar generator end of the extension cord, we will connect our 6 pin trailer plug, just like before. The black ground wire will go to the pin connector labeled as ground. Our white positive wire will connect to the center pin. We will be adding an additional jumper wire as well. This is part of the solution I talked about for having an automatic disconnect for the solar charge controller. You will want to use at least 14 AWG wire, and we will connect it to the pins labeled for the L and R turn signal. After that, we can then assemble the trailer plug and tighten the wire clamp. The extension cord wire also works very nicely with the 6 pin trailer plug. This makes for a really rugged connector.
I also added an inexpensive cord wrap for coiling up the solar panel cable for storage and when we don’t need the full length. I also purchased this from Amazon and the link will be in the video description and blog post. After coiling up the cable, I position it where I want to be mounted on the back of the panel, and used some construction adhesive to glue it into place.
Automatic Disconnect for Solar Charge Controller
The last improvement and modification I made was to add the auto disconnect switch for our solar controller. Originally, I didn’t feel the solar generator should require one, because the solar charge controllers are designed to be connected to the battery 24/7, so I assumed the battery draw should be very minimal when there is no sun light, much like the clock in your car should not run the battery down when your car is parked for a long time.
I decided to measure the current draw from the solar controller when the panels were disconnected. The idle current draw measured at 8 milliamps. While that would still take several weeks to drain the battery, it is more draw than I had expected. I didn’t want to add a manual disconnect switch, because I didn’t want to have to worry about forgetting to turn the charge controller on or off all the time. I came up with a better solution that I am really happy with. We are using a 6 pin trailer connector for our solar panels because they are weather proof, rugged, and very inexpensive. But we are only actually using 2 of the 6 pins. So we can use 2 more of the pins as an integrated disconnect switch.
Earlier in the video we already put a jumper wire across two of the pins in the male plug. Now we just need to find the wire inside our solar generator that runs between our fuse block, and the solar charge controller. Snip that wire, and then splice in a longer wire extensions to each end the wire you just cut. We will be routing these extension wires to the female side of our 6 pin trailer connector. It helps to neaten up the wires before we trim them to so that we can determine the proper length. It is also easier to connect the new wires to their pins if you remove the trailer connector from the case.
Thread the new wires first through the protective cover, and then through the hole in the Pelican case. Then determine the length needed where to trim and strip the ends of the wires. Connect the two wires to the L and R turn signal pins, like before. It does not matter which one goes where, because our jumper wire will short them together, turning on the solar controller, whenever we plug in the solar panels. When we unplug the solar panels, the solar charger is automatically disconnected from the battery.
I will be building some portable quick connect battery bank expander units in the next video in this series. The design will allow for connecting multiple ones in a daisy chain using the 350 Amp Quick Disconnect Port. I will also show you how to add multiple panels. The current design of our solar generator will allow up to four 100 Watt panels to be connected.
Let me know in the comments if you have any additional ideas you would like to see as well.
Acrylic Cover Cut Diagram – Cut sheet with dimensions and assembly information for the protective acrylic cover for our 2000W Solar Generator.
Main Components for the Solar Generator
Additional Components & Supplies
To see the full list of components used in this build, see Part 1 – How to Build a Large solar Generator