Locations for Installing Solar Panel Wiring and Charge Controller

[gordonsick]

I am interested in knowing what route people have chosen for the solar panel cables to the charge controller and where they installed the charge controller.

I realize that the choices will depend on the MH coach configuration, so I'll note that I have a Berk 34QS. It has quad slides and the battery bays and the bay for the Magnum inverter unit are underneath a bedroom slide. I have a closet in the rear, and no rear bath.

So, I really have two related questions:
1. Where to put the charge controller?
2. How to route the wires to the charge controller?

Initially, it seemed best to put the charge controller in the electrical bay behind the Magnum inverter. But, there is not much space there. A lot of other stuff is mounted on the walls, and a bunch of battery wire is looped around and fastened to the wall. I could shorten the battery wires and clean up that mess, but things will be a tight fit. I have an MPPT charge controller that is about 4" by 6" and about 2" deep.

The battery bays have more room, but the batteries are flooded, and I shouldn't put electrical equipment in with them (nothing on my MPPT controller says it is safe in an environment of explosive gas).

Other locations for the charge controller become available, depending on my wire routing, so let me describe my thinking along these lines.

My initial thought was to route the wires down through a cupboard above the TV on the back of the bathroom wall. This wall is fixed and doesn't slide. The outside of the cupboard has the panel with my Magnum ME-RC remote, thermostat and lights indicated tank fill etc. But, with this approach, I'm going through a lot of walls and could hit something buried in the walls, like other wiring. I then have to route the wiring along the coach to get to the battery bay behind he wheels.

After looking at the MH more carefully last weekend (it is in storage), it suddenly occurred to me that if I bring the wires down the back of the coach, I could go into the bedroom closet and route the wires under the floor alongside the water pipes that go from the heater and washing machine to the water bay.

Thinking further along these lines, it occurred to me that I could route the wires down the the louvered box that is for the engine air intake. I could even route the wires outside the coach until I get to the box. And, I could put the charge controller in the air intake box, out of the weather, but still allowing me to see the status lights.

So, I'm interested in people's opinions. Either let me know the hazards of the choices I've listed above, or tell me how you did it on your MH.

It sure would have been nice if FR had pre-wired a solar system.

–Gordon

[NO3putt]

Gordon, let us know how it goes. Can't think of any Berkshire owners that have installed solar.

[silver]

I am just completing my 300 watt solar install. Last part is the remote monitor inside the coach by the rest of the controls. I was able to generate power for the first time today. What I call my electronic bay is the last bay on the passenger side of the coach. I mounted the MPPT controller there with the magnum. As the batteries are right next to this bay it was easy to get to them. I got down from the roof by going through the rear cap, It is hollow. When I get everything done I will post pictures. Plenty of dicor where ever I penetrated the roof to attach the panels and route the cable.

Other routes from the roof could be down the frig stack or down one of the breather vents for the gray or black tank. I have read where people have used all three. It is not recommended to put the charger controller with the batteries due to the explosive gases the batteries give off when charging.

[dan-nickie]

Silver did you mean the last bay on the driver's side?

[silver]

No. On my 2008 the Magnum is in the last bay on the passenger side and the batteries are next Bay. I will try to post pictures this weekend if I complete the last bit.

[dreamin533]

Silver, I have a 2008 Berkshire 360QS and I am going to install solar once it comes out of storage. I talked to the people at forest river and they suggested I use inserts in the fiberglass roof to anchor the panel. They say there is only a thin piece of wood, 1/8th to 3/16 thick under the fiberglass. How did you find the roof on your Berk, was it thick enough for the screws to bite into? Thanks, Roy

[silver]

Originally Posted by dreamin533

Silver, I have a 2008 Berkshire 360QS and I am going to install solar once it comes out of storage. I talked to the people at forest river and they suggested I use inserts in the fiberglass roof to anchor the panel. They say there is only a thin piece of wood, 1/8th to 3/16 thick under the fiberglass. How did you find the roof on your Berk, was it thick enough for the screws to bite into? Thanks, Roy

I am curious who you spoke to at Forest River and when. I contacted them with this question about a month ago and only got silence. As they are normally very responsive I thought it might be a reliability issue. Not wanting to make a recommendation it the event the panel came off while traveling.

On to your question, Yes the roof skin is only about 1/8 inch thick. Renogy recommended the use of well nuts to hold the panels on and they worked great. My next post will have part number and where you can purchase. Once installed I used generous amounts of Dicor to water proof as well as aid the bonding. They will not be going anywhere.

[silver]

As promised the pictures of my solar install on my 2008 Berkshire 39QS.

I began thinking about solar about a year ago. Did my homework and decided I needed a 200 watt MPPT system. I did not want it for cooling or cooking but wanted to run the rest of the coach. As I put together a system I wanted room for expansion so I wanted a larger controller. I also wanted 10Ag wire for the solar panels and 9 Ag wire to the batteries, and Monocrystalline panels. I found to my surprise that putting together a 200 watt system with these specifications was 20% more expensive than the Renogy 300 watt package system of the same specifications. I then waited to purchase until cyber Monday and got another 15% off. My final cost for a 300Watt MPPT system was around $733. to follow is what I ended up with.

Click on picture to enlarge.

[gordonsick]

Silver,
Nice job and description.

When you got the wires through the rear cap, could you see right to the ground, or did it stop at some point where you had to fish the wires?

You've got a lot more space in the electrical (non-battery) bay than I have, so that makes the job easier.

–Gordon

[silver]

Originally Posted by gordonsick

Silver,
Nice job and description.

When you got the wires through the rear cap, could you see right to the ground, or did it stop at some point where you had to fish the wires?

You've got a lot more space in the electrical (non-battery) bay than I have, so that makes the job easier.

–Gordon

I was able to see right down to the ground but where I drilled the hole, to the left of the ladder if facing the rear of the coach it was not a direct drop. I removed the passenger tail light and that enabled me to grab the cable and route it the remainder of the way to the bottom of the coach.

I did remove a screen that was in the bay that took up space. Made the bay look smaller. You just need to be sure that you have enough space around the controller for cooling. You might also consider the bay in front of the battery bay for the controller. Would be a shorter run to rout the MT5 monitor cable.

Can you post pictures of your back bays? Both sides so I can see what they are like?

[gordonsick]

Originally Posted by silver

I was able to see right down to the ground but where I drilled the hole, to the left of the ladder if facing the rear of the coach it was not a direct drop. I removed the passenger tail light and that enabled me to grab the cable and route it the remainder of the way to the bottom of the coach.

Silver,
I'll break my answer up into two parts, since we are covering a lot of territory now.

I did go to see my Berk today and crawled under to see a clear drop down from my back fibreglass cap to the ground on the driver's side. There is no insulation in this space and no source of heat to affect the wiring (exhaust pipes are on other side and the radiator and engine are well out of the way.

I can get my bearings because I can see the inside wiring for the top left rear clearance light. So, I'll drill down from the top and put a small weatherproof electrical box on top. I can put a couple of fuses in there and seal the wire on entry with silicone or something like that. I think I'll run the wiring in a flexible plastic conduit, such as Carlex flexible liquid-tight tubing. I see it in use in my centre electrical bay to deliver wires to my Magnum Inverter/Charger.

There is lots of room to route that to my electrical bays, once I get it to the bottom.

[gordonsick]

Originally Posted by silver

Can you post pictures of your back bays? Both sides so I can see what they are like?

Silver,
Unfortunately, I visited our Berk before reading your request for photos. So I don't have a full set. My Berk has three bays at the left rear for electrical, and one at the left front (to serve power to the coach and generator). I'm concerned about the three bays at the rear here.

Facing the bays, the left bay has 4 golf-cart batteries in it for the house. The right bay has two chassis batteries for the engine. I've got pictures of the middle bay, which is where I need to put the charge controller. As you can see, it is a lot busier than your centre bay. Below these pictures is the space for the 50 amp power cable. The dominant part of the bay is the Magnum Inverter charger, but the walls are filled with electrical items.

The photos below are the Left side of the Bay, the Centre of the Bay and the Right side of the Bay.

At the Centre, you can see the serpentine bit of 12v power cable in the red loom that I plan to shorten. They must have used a standard loom that also covers a bigger RV.
–Gordon

[gordonsick]

Originally Posted by silver

As promised the pictures of my solar install on my 2008 Berkshire 39QS.

I began thinking about solar about a year ago. Did my homework and decided I needed a 200 watt MPPT system. I did not want it for cooling or cooking but wanted to run the rest of the coach. As I put together a system I wanted room for expansion so I wanted a larger controller. I also wanted 10Ag wire for the solar panels and 9 Ag wire to the batteries, and Monocrystalline panels. I found to my surprise that putting together a 200 watt system with these specifications was 20% more expensive than the Renogy 300 watt package system of the same specifications. I then waited to purchase until cyber Monday and got another 15% off. My final cost for a 300Watt MPPT system was around $733. to follow is what I ended up with.

I had purchased a couple of 100 Go Power Flexible panels with PWM controllers, and then decided I needed an MPPT controller, because I wasn't getting a charge in the low winter light I have. (I just put the panels in my front window facing SW, hoping that the low winter sun would catch them nicely and it had trouble getting enough voltage to charge, while also shedding any snow.)

One of the advantages of an MPPT controller is that I can put the panels in series to get higher voltage in low light, and let the controller manage the output voltage in better light.

So, I ordered a 60 amp Solar Mate system. It can be seen on eBay at eBay
but I ordered it from Amazon Canada at
https://www.amazon.ca/quality-MPPT-S..._sim_sbs_504_1

In theory, I can get 600 watts of power by running two banks in parallel that each contain 3 panels in series (6 panels all together). Each bank would have a maximum voltage of 51 volts (3 x 17), and the controller maxes out at 55 volts input.

The manual for the controller talks about an RJ45 port for a display panel to go inside the coach, but I can't see anybody selling these. It would be nice to read the volts and amps while I'm in the coach.

BTW, the MPPT controller with 200 watts of panels couldn't keep my batteries charged over the winter. At 51 degrees of latitude, the idea of putting them in the front window just doesn't get enough power. I didn't have time to mount them on the roof and was worried that snow would block it.

But, I'm hoping that everything is functional, so that by putting the two panels on my roof, I can keep the batteries charged while I'm storing it away from shore power, when I'm not in a snow zone.

I'll report back on that project later.

–cheers, Gordon

[Blackhat6mike]

There is a rubber insert that the mounting screws expand. You drill the hole, insert the rubber "plug" into the hole, then run the screw down through it and it expands to make a really tight and waterproof connection. The screw and expanding plugs are expensive, but work great for thin roofs. Got mine from HD.

[silver]

Originally Posted by gordonsick

So, I ordered a 60 amp Solar Mate system. It can be seen on eBay at eBay
but I ordered it from Amazon Canada at
https://www.amazon.ca/quality-MPPT-S..._sim_sbs_504_1



–cheers, Gordon

Have you thought about mounting the controller in the rear closet? Might be a good spot. Solar cables come down the back of the coach right behind it. Plenty of room. Then take cable out to battery. As for remote I wonder if the Renogy MT5 remote would work? Renogy does not make it they buy it. I have seen it used on other MTTP controllers. Just a thought. Also use Dicor to patch any spot you go through the roof, not silicone. Flex panels are nice. I did not want to go the extra expense for them but they say you can even walk in them. I also want to have my system keep battery up when away from electricity for long periods of time.

[silver]

Originally Posted by Blackhat6mike

There is a rubber insert that the mounting screws expand. You drill the hole, insert the rubber "plug" into the hole, then run the screw down through it and it expands to make a really tight and waterproof connection. The screw and expanding plugs are expensive, but work great for thin roofs. Got mine from HD.

They are called well nuts

[gordonsick]

Originally Posted by silver

Have you thought about mounting the controller in the rear closet? Might be a good spot. Solar cables come down the back of the coach right behind it. Plenty of room. Then take cable out to battery. As for remote I wonder if the Renogy MT5 remote would work? Renogy does not make it they buy it. I have seen it used on other MTTP controllers. Just a thought. Also use Dicor to patch any spot you go through the roof, not silicone. Flex panels are nice. I did not want to go the extra expense for them but they say you can even walk in them. I also want to have my system keep battery up when away from electricity for long periods of time.

Silver,
Good thought on the closet, but this is why I'm not going that route:
The MPPT controllers generate heat – at least there is a big heat sink on mine and they say to mount it vertically, so that heat flows through it. Thus, a closet would have poor ventilation and would present flammable material.

I might have to mount the controller in the bay below the Magnum charger and share space with the power cable.

I might also be able to mount it behind a flexible bit of material at the back that goes between the metal frame and the rear end cap. This goes the full height of the radiator. I haven't removed the screws to see how much room I would have, though.

On the remotes, there is an interesting question as to whether there is a standard control chip in several models. If so, the same remote might work for several control units.

I've often heard people recommend Dicor, but is it needed only for rubber roofs? My roof is fibreglass.

The Carmanah GoPower people recommended using Sikaflex to glue the panels to the roof, when I enquired by email. Sikaflex | Sika Corporation U.S.

My specific concern was how to glue the panels, since they are on a pretty hard plastic substrate that might not be gluable. But, the Sikaflex seems to be a good overall adhesive for roofs and it seems to be available in places like Home Depot.

–cheers, Gordon

[silver]

I would use what solar company recommends to glue panels down then use Dicor around edges. If you look at your roof the white material around the seems and roof vents is Dicore.

I was thinking about the closet for a mounting location. If you mounted it low, most closes hang high like shirts leaving the low area open. You could but a rat wire screen around the controller if you were concerned. My Mppt controller has an operating spec of 55 Degree C or 131 Degree F. Not enough to start a fire. Just need to be sure it can get air to cool. Just a thought. Remember they are not rated for outside mounting.

[ScottBrownstein]

Awide variety of panel "feet" and those great well nuts. You want clearance under the panels since they really don't put out a lot of power when they get hot. The air space will help.

[gordonsick]

I prefer the idea of minimizing the number of entries from the roof to the living area, since they all have a risk of leaking. If I put the controller in the closet, I have to enter the living area and then leave it. If I put it outside, I never have to pierce the living area.

The Carmanah person recommends using the Sikaflex around the edge of the solar panel. In particular, he gave another option to use a two sided 3M VHB (very high bond) tape to hold the panel down and then use Sikaflex around the edge. I might use that option, since I would be wearing a belt and suspenders, then.

An advantage of Sikaflex is that it can be readily obtained from hardware stores, rather than RV dealers, which is handy if I don't buy enough to finish the project. If you look at the data sheets on Sikaflex, it is widely used in demanding architectural situations, such as bonding fabric, metals and cement/stone surfaces. They make a lot of different products, but I suspect the one that Home Depot carries is suitable for bonding to fibreglass and metal. The hard thing to bond to is the plastic on the solar panel, since it seems to be a variant of polyethylene.

Unless Dicor is specified as bonding to polyethylene (few glues are), I think it would be a poor choice, even around the edges of the panel, since a crack would open up and invite water in.