(Posted to Reddit and
Casita Forum as well)
We just bought a 2018
Casita LD and the first project was to get some
solar on the roof to keep the
battery topped up. Having built out a camper van a few years ago, this wasn't new to me but I’m by no means an expert, just a well-researched amateur. All in all, this was a pretty simple install and relatively cheap. I know there were a number of
solar threads but I know when I was starting out how helpful it was to have a step-by-step guide so I hope this helps others looking to do similar.
Parts list:
- Renogy Bifacial 115-watt square solar panel - $100: This is a perfect fit between the fan and bathroom exhaust. It is bifacial which means technically it could charge from the underside as well. I didn't need this feature but the dimensions fit perfectly and it was the same price as a non-bifacial (when purchased on Amazon)
- Victron SmartSolar 30-amp MPPT controller w/ Bluetooth - $128: You can get other controllers for cheaper but Victron makes the best and this is an exceptional price. It includes Bluetooth monitoring via the app. The single panel only requires about 8 amps but this allows plenty of room for expansion in the future
- Z-brackets - $15: I initially tried to purchase the adjustable brackets to slightly angle the panel so as to take advantage of the bifacial feature and to allow great surface area for adhesion but ultimately those brackets required too much modification to adapt to the curve of the casita so I went with the traditional z-bracket
- Renogy 10' 10 AWG solar cable - $20: Exactly the correct length to run from the panel, through the gray water vent, and to the tow connector in the closet. 115-watts wouldn't require 10 AWG wire but in case I decide to add more solar panels in the future, I could still use these cables. Also, the cable run from the 7-pin connector is 10-gauge and consistency is neat.
- 30-amp breaker - $16: This runs between the panels and the controller. I prefer this to a fuse since it allows me to easily disconnect the solar from the controller when needed
- VHB 4950 Mounting Tape - $16: I reached out to 3M to inquire what tape to use to mount aluminum to fiberglass and explained my use case. This is the tape they recommend along with...
- (Optional) 3M Tape Primer 94 - $26: This isn't required but was recommended by 3M and since I don't want the panels flying off, the slight extra expense was worth it for peace of mind.
- (Optional) Eternabond 3" Rubber Repair Tape - $19: Again, probably not necessary but provides extra peace of mind
- Electrical tape
- Wire nuts that can accommodate 3x 10AWG wires
- 3x 10 AWG Ring terminals
- (Optional) Wire crimper, shrink tubing: This is preferable to have more solid connections but if you don't have access to all the fancy electrical stuff, you can just use electrical tape and pliers
- Some extra 10 AWG wire, About 4' is plenty, cut into 2x 18" segments and one 12" segment.
- (Optional) Loctite Blue Threadlocker: Recommended for ensuring the bolts that attach the panel to the bracket don't come loose.
Tools required:
- Flathead screwdriver
- Drill and 3/16" bit
- 8 1/2" screws
- 6mm wrench or socket
- Wire strippers and cutters
Steps:
MOUNTING THE SOLAR
First I attached the z-brackets to the panels and put a drop of Loctite on each bolt. The bolt size is 5mm. The order is (from inside the panel) bolt, locking washer, washer, panel, bracket, washer, nut.
Next, I placed the panel on the roof of the Casita to test the fit. I positioned the panel with the brackets on the front and back rather than side-to-side for 2 reasons: a) Since the wind is coming mostly from the front, I figured this would provide more strength. No idea if this is true or not but it makes sense in my head. b) this positions the wires on the side closest to the gray water vent coming out from the closet which is where I want them. The cables should be on the door side of the Casita.
I determined how much I need to bend the brackets to accommodate the slight slope of the roof and bent accordingly. The brackets are aluminum so they bend easily with just your hand or pliers.
Once I had a flush fit and centered on the roof, I traced the outline of the brackets in pencil. Next I cleaned the mounting points on the roof and brackets with alcohol and applied the 3M tape primer (recommended by the representative at 3M) with a Q-tip.
Once everything dried, I applied the VHB tape to the brackets. Next I placed the panel on the roof making sure the cables are on the Casita door side and the bent brackets in the front. I aligned the brackets with the outline I drew and removed the film from the VHB first on the driver’s side, leaving the protective film on the passenger side tape. I pressed firmly for 30 seconds to ensure a good adhesion. Moving to the passenger side, I pulled the cables out from underneath the panel, removed the protective strip from the VHB tape and affixed the panel to the roof, again pressing firmly on the brackets for 30 seconds. Then I left some
weight on the panel overnight to help the VHB tape to adhere and ensure a flush fit.
ROUTING THE WIRES AND ATTACHING THE CONTROLLER
On my model the vent cap for the gray tank above the closet just lifted off with a little pressure. It looks like there was supposed to be a screw there but it was missing. Other models may require drilling out the rivets.
From inside the closet I drilled two holes through the elbow of the PVC pipe directly below the vent with (I think) a 3/16” drill bit. I fed the wires through the vent into the closet and routed them along the wall behind the PVC.
NOTE: the wires are the same color so you need to keep track of which is positive and which negative. The MC4 connector has a tiny + or - on it to help but once the wires are on the inside, you won’t know unless you label them.
Next I attached the solar controller to the wood hatch at the bottom of the closet covering the wires. This may or may not be the best place for your setup but it has the benefit of providing a nice run of 10 AWG wire to the
battery.
CONNECTING THE CONTROLLER TO THE
BATTERY
I cut two lengths of 10 AWG wire about 18” long and stripped them. On one side of one of the 18" wires and one side of the 12" wire I attached a ring terminal with shrink tubing.
Electrical tapes works also
Next I connected the wires to the Casita battery. It’s a good idea to disconnect the battery first to make sure you don’t accidentally short the wires.
NOTE: Casita uses black or yellow for hot and white for neutral. Most solar connections use red for hot and black for neutral or, as in the case of the wires linked above, black for both. Confusing, I know.
I connected the positive (hot) wire with the ring terminal to the small red fuse mounted on the floor and the other side to the positive battery connection on the solar controller.
Then I connected the other 18" wire to the negative battery terminal on the controller. I opened the IDC connector (aka tap splice) for the neutral (thick white wire) and swapped it for a wire nut that joined all three wires (the two that were already connected and the negative coming from the solar controller) together. A little electrical tape kept everything secure.
Once both battery wires were connected, I reconnected the battery and the controller came alive and could be set to the appropriate battery type and charging profile. For the Victron controller and the AGM battery I have that was apparently the default profile (confusingly named Gel Victron Deep Discharge). You do not want the “AGM Spiral Cell” profile which is not for AGM batteries. I recommend downloading the app for more controls and to track usage.
CONNECTING THE
SOLAR PANEL TO THE CONTROLLER
Once the charging profile is set, I connected the negative solar wire to the controller. I mounted the 30-amp breaker next to the controller. I attached the third ring terminal to the positive solar wire and connected it to the breaker. I took the 12" wire with the ring terminal and connected that between the solar controller and the breaker. Ideally the terminals will be crimped and shrinktubed but pliers and electrical tape also work. Once all the wires are in place, give a firm tug on all the connections to make sure they’re not going to come out.
Head back up to the roof and connect the MC4 connectors and ziptie everything in place to make sure it’s not going to flap in the wind.
FINALLY...
Check the Victron app to see if everything is working and the controller is charging.
If everything is working correctly, replace the vent cover and screw or rivet it down. It’s a good idea to have a dip in the wires before they enter the vent so that any water running down the wires won’t enter.
Last, I caulked the holes that were drilled for the wires and ziptied everything in place in the closet.
A couple days later I applied Eternabond over the brackets as a secondary measure to ensure they won’t come loose and to keep water and dirt from working their way under the VHB tape.
And Bob’s your uncle.
Linear Mode
