Project: Solar and Battery bank addition for an RV
The Project: to install 4 – 140 Watt solar panels, 6 – GC2 208-amp hour golf cart batteries for storage and all related hardware onto an RV.
The Purpose: to allow the ability to boondock for extended periods of time. To act as a backup power supply for the home in the event of power outages. For the prepper side of me it’s also a bug-out vehicle. And well… I thought it would just be cool to do.
The Beast aka the “Man Van” a 1991 Fleetwood Bounder 31’.
The inspiration: My gratitude goes out to two individuals who sparked my interest and provided me with a wealth of knowledge and information which in turn gave me the confidence to take on and complete this task.
- Eddie at rvhappyhour.com for his work, videos, photos, and information on his 5th wheel solar project as well as his personal feedback.
- Steven Harris at www.battery1234.com for his battery bank videos, information and a whole lot more.
- Ray at rvhappyhour.com whose original video of Eddie’s system was the inspiration for this project. His YouTube channel https://www.youtube.com/user/LoveYourRV has also given me lots of ideas for RV stuff.
Challenges and Concerns:
- The existing coach battery(s) sat in the compartment right behind the front bumper. All coach battery connections terminated there as well. I decided to use the largest storage compartment just behind the front passenger side wheel for my project. In order to do so I needed to make longer battery cables that would run from the new battery bank to the existing coach battery connections.
- I was also a bit concerned about the weight of the additional batteries but after having the RV weighed at a truck scale I determined I would still be within the vehicles specs.
- 4 – Kyocera KD140SX-UFBS 140 Watt Solar Panels
- 1 – TriStar TS-MPPT-45 Solar Charge Controller
- 1 – Progressive Dynamics PD9270C Power Converter
- 1 – TriMetric TM-2030-RV Battery Monitor
- 6 – GC2 208 Amp Hour 6-volt Golf Cart Batteries (624 total Amp Hours storage @ 12 Volts)
Solar Panel Mounting Materials
- 1½” x 1/8” aluminum angle (for foot and panel frame)
- 1” x 1/4” aluminum bar for support rods
- #12 x 3/4” Sheet metal screws (to mount bracket to panel)
- #14 x 2” Sheet metal screws (to mount brackets to RV)
- 5/16” X 1” Hex bolts (for connecting support rods and panel bracket to base bracket
6 needed per panel (4 for when panels are down, 2 for support rods when panels are up)
- 5/16” Wing nuts (6 per panel)
- 5/16” Lock washers (6 per panel)
- 5/16” Washers (12 per panel)
The Panels, Panel Brackets, Support Rods and Base Brackets
As I started writing this I quickly realized that some of the terms I was using for the brackets were easily interchangeable and thus confusing. So, I decided on the following terms in hopes that it’ll make things a bit easier to understand.
Panel Bracket: the bracket that mounts to the Solar Panel
Base Bracket: the bracket that mounts to the roof of the RV
Supporting Rod: the rod that holds one end of the Solar Panel up so it can be angled toward the sun. One end is bolted to the Base Bracket and the other to the Panel Bracket via 5/16” bolts.
Attach/Mount: I use the term mount to indicate the permanent connections and attach to indicate the temporary connections. Each of the brackets have two connection points. One is mounted to something via screws (roof or Solar Panel) and the other is attached via bolts (panel to roof or to the supporting rod).
Mounting Holes/Bolts: The 5/16” holes that accept the 5/16” x 1” hex bolt.
Base Bracket (sorry about the glare)
- 4 per panel
- 5” long 1½” x 1/8” aluminum angle
The placement of the single panel mounting hole is important as it, in conjunction with the hole placement in the panel bracket, allows the panels to pivot without contacting the roof of the RV and thereby damaging it. You may also reduce this possibility by angling or rounding the corners of the panel brackets but do so after drilling the holes in order to more easily measure and drill them consistently.
- I mount the Base Brackets to the roof using 3 – #14 x 2” sheet metal screws (per bracket). 9/32” holes work well for these screws. At least on my RV any screw smaller than this didn’t seem to hold securely.
- I attach the Base Bracket to the Panel Bracket and/or the Support Rod using a 5/16” x 1” Hex bolt, washers, lock washers and a 5/16” Wing Nut. This does secure the panels quite well, especially when using lock washers, but it is a bit time consuming removing and reinstalling them when either raising or lowering the panels. I have considered possibly using quick release pins but they’re quite expensive. Another option is to tack weld the nut to the back of the panel bracket and then use knobs with threaded studs. Still a bit expensive but cheaper than quick release pins.
Update: I decided to use 5/16” Clevis Pins and Hitch Pin Clips to attach the panels to the brackets and support rods.
- When mounting the Base Bracket to the roof it’s best to mount the Panel Bracket to the panels first then attach the panel to the Base Bracket using the 5/16” bolts, align the panels where you want them and then screw the Base Brackets down. You might also want to slip a washer in-between the Base Brackets and Panel Brackets just to give yourself a little bit of clearance for when you raise and lower the panels. This is just for the purpose of initially mounting the Base Brackets to the roof. Doing this on just one side of each panel would probably be enough space.
- I also put a generous amount of Dircor Self-leveling Lap Sealant under each bracket before mounting it as well as in the screw holes before screwing the brackets in place. After they’re all in place I seal around the brackets and screw heads to prevent any moisture from getting in.
Panel with brackets attached is aligned where I want them on the roof. With the Base Bracket connected to the panel I applied Dicor sealant beneath the brackets and then screwed them to the roof using #14 x 2” sheet metal screws. I then sealed around the brackets.
Base Bracket mounted on roof
The panel brackets are currently secured to the base bracket using a 5/16” bolt with 2-washers, 1-lock washer and a wingnut (right). They work well but once the lock washer is compressed you have to use a ratchet and pliers to loosen them. I might try using a clevis pin and hitch pin clip (left) for easier and quicker transition between raised and lowered.
Panel Bracket ready to be attached
- 2 per panel
- Length – dependent upon the length of the short side of your solar panels. (1½” x 1/8” aluminum angle)
The placement of the 2 Panel Mounting Holes on the bracket (the holes which align with the Base Bracket) is important as it, in conjunction with the hole placement in the Base Bracket, allows the panels to pivot without contacting the roof of the RV and thereby damaging it. You may also reduce this possibility by angling or rounding the corners of the Panel Brackets but do so after drilling the holes in order to more easily measure and drill them consistently.
- The Panel Brackets are mounted to the Solar Panel using #12 x 3/4” Sheet metal screws. I drilled the holes in the brackets first then aligned the bracket on the panel, marked and finally drilled the holes in the panel. I used 5 screws per bracket spacing them evenly.
- You might also want to drill one additional 5/16” hole at the midpoint of bracket to allow for an additional steeper angle when the panels are raised.
Panel Bracket attached to the panel.
- 2 per panel
- Length – same length as the Panel Brackets. (1” x 1/4” aluminum bar)
The placement of the 2 attachment holes on the Support Rod is identical to those on the panel brackets. You can use the Panel Brackets as a template for drilling the holes in the Support Rods. By doing this you can leave the Support Rods attached to the base/panel brackets when they’re dropped down for travel/storage.
Note: I originally measured cut and connected and glued all the conduit and junction boxes before running the wiring. I quickly discovered that pulling the 10 AWG wiring through the conduit, even after straightening the conduit, was extremely tough. I broke the end off of one cable puller and had to use my larger puller to complete the job. If I were to do this again I would pull the wire before actually connecting the conduit to the boxes. I might even consider going with 3/4” conduit instead of 1/2”. Once the wire is run through the conduit, connectors and junction boxes I’d then connect and glue them together. It might be a bit messier but I think it would be easier to do.
All the wiring on the roof was ran through ½” Flexible Non-Metallic Liquid-Tight Conduit (purchased at Menards). And connects through a couple Carlon FS boxes to a Carlon Type X Conduit box.
Conduit connected to Solar Panel junction box. 10 AGW multi-strand wiring is used to connect the panels to the main junction box.
Each panel’s conduit is connected to a junction box. Each pair of the panels shares a conduit. So the two on the driver’s side join to one junction box and continue to the main junction box, same with the two on the passenger side (drivers side conduit shown).
The conduit for each pair of panels were connected to a Carlon FS box which then ran to the main junction box. The junction box is attached to the roof with two screws. Dicor sealant is applied to the bottom of the box before attaching.
The two drivers side panels and conduit.
The main junction box (shown with only one conduit connected). I mounted 2 terminal ground bars (cut and ends beveled to fit) into the box. These fit pretty tight but I also screwed them into place as well. A hole was drilled through the center of the box and roof so I could run the wiring down through the RV and into the compartment where the batteries and equipment would be mounted. I applied a liberal amount of Dicor sealant to the bottom of the junction box and screwed it to the roof.
Visible – the main junction box (round) and the passenger side panel junction box. The driver’s side panels feed into one side of the main junction box and the passenger’s side panels feed into the other side.
All the conduit is secured to the roof using clamps and screws. Dicor sealant is applied to the screws when installing them
I decided to replace the bolt and wing nuts and instead use 1” by 5/16” Clevis Pins and Clip. This makes it a whole lot easier and faster to raise and lower the panels.
I purchased the pins and clips through Fastenal. The Clevis pins can in a bag of 30 which was perfect for what I needed. The Clips however came in a quantity of 100. I’m sure I’ll find some use for the extras in the future.
Battery and component installation
On my RV the compartment best suited for storing the batteries and electrical components with close access to the engine compartment was just behind the passenger side front tire. The entire compartment was carpeted but had plenty of room to be able to install everything I needed.
I lined the bottom and sides with some spare plywood I had on hand. These were screwed to the compartment walls and floor. The rods you see are the rods for battery hold down clamps. I temporarily installed the batteries, marked out the end points for the batteries, drilled holes for the L-shaped rods, inserted the rods from beneath the plywood then screwed down the plywood.
The visible hole in the back is for running the 2 AGW wiring to the engine compartment where the Shunt is located. I used 2 AGW welding cable for the battery wiring. It was on sale and is quite flexible. There is a 1” PVC connector inserted in the hole I drilled in the wall to prevent chafing on the vehicle sheet metal wall. I zip-tied the cable (using heavy duty zip-ties) to existing lines between the exterior of this compartment and the forward compartment.
Batteries installed. I used two pieces of plywood with holes drilled aligning with the battery hold down rods along with washers and nuts to hold down the batteries. A 2×4 is mounted to the left of the batteries to prevent them from sliding.
2 – 250 Amp Bus Bars are mounted on the back wall. The TriStar Solar Charge Controller, Disconnect Box, 60 Amp Circuit Breaker and 100 Amp Fuse are mounted on the left wall.
The shunt required for the TriMark battery monitor had to be mounted to the frame in the engine/battery compartment in order to reduce the amount of cable ran between compartments. Two Insulated Battery Power Junction Post Blocks were also mounted on the frame to make it easier to tie the vehicle and cabins electrical systems together. The 2 original cabin batteries were mounted just forward of this frame. You can see one of the battery clamp rods at the bottom of the photo just right of center. The 6 GC2 batteries now replace those.
Completed electrical compartment mods.
The power cords connected to the Inverters are connected to 2 outlets in the RV cabin. The inverters can be powered on from the compartment or individually via a 3-way switch in the cabin.
Because of how the connections are made to the Shunt there are 2 negative cables and 1 positive that run from the forward compartment to this electrical compartment. See wiring diagram for details.
The RV Cabin
The wiring from the main junction box runs into the cabin just above the door. I haven’t decided whether I’ll put something over this to hid it or not. For now, I’ll keep it as is.
I run the wires down through a LeGrande/Wiremold Cordmate channel. It’s got a self-adhesive backing and the channel itself snaps open/close. The 2 power wires run all the way down to the floor and through a hole which enters into the electrical compartment.
The TriMetric TM-2030-RV Battery monitor is mounted in the cabin above the electrical compartment. Also mounted on the same wall is a 3-way switch which turns the Inverters on/off. Note: only one can be turned on at a time using this switch. The wiring for both run from the floor through another LeGrande/Wiremold Cordmate channel.
This is the lighted 3-way switch used to turn on/off each of the inverters. The depth was greater than I had hoped for so I ended up using a rather deep outlet box. If I can find a slimmer and/or flat mounted switch, I’ll swap it out.
The inverters are connected via 2 – 6 ft. 14 AGW power cords to two separate outlets. The red one is for the 1600 Watt inverter and the white for the 800 Watt. The enclosure both provides a place to mount the outlets as well as covering the holes the Panel and component wiring runs though. This will eventually be either stained or painted. I may add two additional outlets farther back in the RV beneath the kitchen cabinets if I’m able to run wiring from the electrical compartment over to those cabinets.
Additional Electrical Mods
In addition to the solar mods I also replace the original power converter with a Progressive Dynamics PD9270C Power Converter. The old converter weighed about 15 lbs. and buzzed when power was applied. This new one is about the size and weight of a PC power supply and completely silent when running. It’s also 70-amp vs. the original 30-amp converter.
I also installed a Progressive Industries EMSHW30C internal Surge Protector. It was a bit more expensive than the plugin types but I’ll never have to worry about someone stealing my surge protector.
TriStar Remote Meter-2
Connects to the TriStar TS-MPPT-45 Solar Charge Controller and allows monitoring and diagnostics of the Charge Controller.
Additional Disconnect Switches
I’ll probably add two disconnect switches allowing me to cut off power to/from the batteries and the power converter. This will make things easier if/when I need to work on some of the system components.
Change Panel Wiring Configuration
The panels are currently wired as 4 strings of 1 panel each in parallel. This produces a max of 560 Watts @ ~16-volts min. However, this can result in lower voltages when there’s less sun. If I change this to a configuration of 2 strings of 2 panels – each string in series. I still get a max of 560 Watts but at ~34-volts min. This gets me a higher voltage output with the same light input. The controller will cut off power to the batteries if the power is too low so the second option allows for a longer period of power production through the controller. The MPPT controller can handle a higher input and still produce a 12-volt output for the batteries. It wouldn’t be hard to change to that configuration with how my current wiring is ran.
May Replace the GC-2 6-volt batteries with 12-volt when these finally reach end of life. This could allow me to double my capacity without adding additional batteries. I’ll make that decision after I’ve had a chance to really test the current configuration. Cost wise the 6-volts are a better deal but your Amp Hours remain the same when combining two 6-volts in series to make one 12-volt. 6 12-volt batteries ran in parallel would multiply the Amp Hours by 6 (if all have the same Ah rating). A long term option may be to use Lithium Ion batteries if the price drops enough in the next few years.
I have enough room to add 2 additional panels. So far even with the panels down the existing configuration has been able to recharge the batteries fairly quickly during the day. I haven’t had a chance to really put a load on the system yet but I have time to test everything before making that decision. I do have one limitation with the Solar Charge Controller I’m using when it comes to adding additional panels to what I already have. I’m maxed out as far as power input goes. The controller can safely handle a greater input but max output remains the same. What additional panels can give me is an increased input/output when conditions aren’t peak over what the 4 panels I currently have produce. I can increase the max output slightly by also upgrading to the next model controller. 2 additional panels would still exceed the max input but I would have some gain. I’d also have to do some rewiring to accommodate it. Can’t justify the cost at this time.
Larger Inverter (3000 Watt or greater)
I’ll probably add one more inverter. The 1600 Watt does a pretty good job but there are some devices I’ve connected which have drawn more than it can handle (at least initial draw). Having 3 different inverters gives me much more flexibility. The issue will be either finding a 4-way toggle switch or coming up with a way of wiring in multiple switches for remote powering of the inverters.
Electrical and other Components (found on Amazon)
1 – Progressive Dynamics PD9270C Power Converter
1 – Blue Sea Systems ANL Fuse Block with Insulating Cover – 35 – 300A 1 – Blue Sea Systems ANL Fuse – 100 Amp
1 set – Positive Insulated Battery Power Junction Post Block 3/8 Lug X 16 (Red & Black Set) 2 – Blue Sea Systems MaxiBus 250A BusBar with Four Terminal 18 Studs of 5/16-Inch
2 – Blue Sea Systems Insulating Cover for PN 2127 and 2128 MaxiBus 1 – MinnKota MKR-19 Circuit Breaker 60A Waterproof
1 – Progressive Industries EMSHW30C Surge Protector 1 – Whistler XP 800i 800-watt Power Inverter
1 – Whistler XP1600i 1600-watt Power Inverter
Dicor Self-leveling Lap Sealant
4 – Kyocera KD140SX-UFBS 140 Watt Solar Panels
TriStar TS-MPPT-45 Solar Charge Controller
TriMetric TM-2030-RV Battery Monitor
Cables for connecting batteries (best pricing I found was from batteriesinaflash on Amazon)
AWG #1/0 Red Battery Interconnect Cable 12″ with 3/8″ Lugs
AWG #1/0 Black Battery Interconnect Cable 6″ with 3/8″ Lugs
AWG #1/0 Black Battery Interconnect Cable 12″ with 3/8″ Lugs
Parts I got from Menards
1/2″ Flexible Non-Metallic Liquid-Tight Conduit 1 – Carlon Type X Round Conduit box
2 – Carlon 3-way non-metallic Conduit boxes Eaton 60A Outdoor Disconnect
Terminal Ground Bar
3/8 & 5/16 2-AWG Battery Cable Lugs
Misc cable lugs, ring terminals, butt connectors, bullet splices, cable clamps, zip ties.
25’ 2 AGW welding cable (it was on sale and works great for connecting batteries to Bus Bar and shunt) 16 & 14 AGW multi strand wire
10 AGW multi strand wire (used to connect the panels to the junction box on the roof) 6 AGW multi strand wire (used from junction box on roof to disconnect box) LeGrande/Wiremold Cordmate cord channels
2 – 6 ft. 14 AGW 3-wire power cords Misc screws, bolts, washers, etc.
5/16” Clevis Pins (0156739 – bag of 30) Hitch Pin Clips (0156981 – bag of 100)
Batteries purchased from SAM Club
6 – GC2 6-volt Golf Cart batteries 208 Amp
Parts from auto supply shop
Battery Hold Down Clamps