Trailer Solar Setup

#elbowsup

DIY camping trailer - #elbowsup Electrical Setup This video complements this page.

The solar setup
The search started with the solar panels. We needed a very specific size to make use of the roof surface. We found solar panels that would produce over 500 watts.
We already bought a water heater from The Cabin Depot in New Brunswick during COVID and were very happy with their service. They have solar systems and, based on my requirements, they sent a quote.

When we ordered the solar panels, we haven't researched the inverters yet. We had to get the power consumption from our 120 volt equipment first. Then find an inverter that generates clean 120-volt plus/minus 5% as per electrical specifications. That actually took some time. Many of the inverter manufacturers didn't confirm the power output (above 114 volt).
And we needed batteries. First we planned to use lead-acid batteries, but the weight was a problem. We found a solution from CANBAT in British Columbia.

Solar Panels and Charge Controller
We purchased two GMA 275 Watt Poly Solar Panels. They are manufactured by GMA in Quebec.

The matching Charge Controller is the EPEVER 40A XTRA4415N-XDS2 MPPT Charge Controller plus 1.5 meter solar panel extension cables. This is a simple unit without an app on the phone and the initial tests performed as expected.

Batteries
The 100 Amp Cold Weather Lithum Iron Phosphate batteries from CANBAT were back-ordered. Not a problem for us, we didn't need them immediately. They arrived 8 weeks later, but I wasn't ready to test them. Still had some open issues with the layout of the trailer.
The battery connect to an app on the phone that shows the charge and some other information.

Inverter
Our search for the inverter brought us back to CANBAT. We decided to get the Rich Solar 3000 Watt 12 volt Industrial Pure Sine Wave Inverter. Yes, it is total overkill, all we need is about 1000 Watt. After reading many horror stories about buying an inverter for the exact requirements, the $100 more for 3000 Watt is not crashing the budget (we passed that point some time ago). There is no problem with our 200 Amp battery capacity, they can easily feed the inverter.

Lithium Batter Charger
Remember when I said that it's always raining? Rain means not solar power and therefore empty batteries. So we got the CANBAT 12V 25A Waterproof Lithium Battery Charger (LiFePO₄). We can always get a campsite with shore power to charge the batteries. But sometimes that does not work either. So we have the Honda EU1000 generator that works with the Battery Charger. The charger uses 410 watts; no problem. Yes, I had it running for 20 minutes and got about 10 % charge into the battery.

Connecting the pieces
It is not plug and play, nor is it rocket science. All components need a switch and/or a fuse to protect them.

Let's start with the solar panels. They produce voltage that can hurt you. The two panels in our setup generate over 500 watts and with over 50 volts, it is dangerous. Our panels are connected in series, where the negative of one panel connectd with the positive of the other and therefore doube the voltage. To protect the equipment, I have an inline fuse on the positive side that connects to the charge controller. You have to get the correct fuse and make sure you get spare fuses as well.
There are "solar fuse size calculator" on the internet. Use them to figure out the size.

But we are not done with the solar panels yet. You also need a switch to completely disconnect the panels from your equipment, both cables, the positive AND negative. These are special "Solar Disconnect Switches". Search for them by name. They may have a fuse as well, but it will not replace the inline fuse from before. And most importantly, never unplug the cables without turning this switch or breaker off. As I was researching the topic, unplugging a solar panel that is active may spark.

The cables and the batteries
The last consideration when buying solar panels, calculate the length of the cables you need. When I placed the order, The Cabin Depot knew the panel rating and could make a cable that is safe. Keep in mind that the cable thickness, or gauge, depends on the volt, amps and length.

Now that we have solar power, we need to store that power in a battery.

This is the power box for the positive power of the two batteries. The batteries can be disconnected individually. Each battery is fused individually. One cable connects to the Charge Controller and the other to the Inverter.
The 12 volts 200 Amps to the batteries, charge controller and inverter, the cables must be thick. I looked up the cable gauge on one of the many cable size calculators and a 2 gauge cable was sufficient. Buying 2 gauge cables is not cheap. I found a solution to save me at least 50%. I got a 25 foot car jumper cable from Princess Auto for less than $30. The O-ring terminals came from Aliexpress, so did the heat shrink. I was able to crimp all the cables with the exact length I needed.

You may notice the two black x-jumper cables connecting the fuses to the 'Common Terminal Plat'. They are not as fat as the 2 gauge cables. How come that they are thinner and still work with the 2 gauge. That illustrates that the cable length is critical in the wire size.
First, I had to calculate the gauge equivalent of 4 houshold sold copper wire, twisted. Yes, there is an app for that. Then I added the volts and amps and the result was that they can carry the load up to 4.5 inches in length. When we ran the coffee maker, I touched the cables to see if they heat up, nope. Same when the solar panels produced power at 80%.

The inverter
This is how the setup looked like. The inverter draws power directly from the power box. Only the switch and fuses in between. Our charge controller couldn't handle the 80 Amps draw needed to run the inverter for our needs. The coffe machine runs less than a minute for one coffee, so the overall drain on the battery is minimal. We will do more detailed testing soon, with actual numbers and examples. One of these tests will be the Kuradori cook plate. We know that kettle and toaster will actually work, but we have no plans to use them. However, running the laptop computer for one hour will be testted, so will the external computer screen.