FYI Solar 101 - A General Guide to Solar in your RV or Motorhome

[Neal]

I am not a solar expert but I have learned a lot from others here mainly @Chuggs who guided me through my solar install which I mirrored his setup and then took it a few steps further. I wanted to share what I have learned to date as it may help others and I welcome others that also installed solar to add your opinions, correct me where necessary, and help to educate the RV community with where we are with solar as of this writing closing out 2019. These are only my opinions, it's okay if you don't agree, take from this what you want, discard what you don't want. I am writing this based on my knowledge of my coach brand - Newmar, others may vary.

Solar Prep

If you have the opportunity to order your coach you may be presented with an option to add solar prep. In my opinion everyone should add this option whether you intend to add solar or not. The next owner or owner after that may want to add solar and having these few wires run at build time will sure make adding solar an easier endeavor. At the time of ordering your coach you may have no plan to ever use solar and later change your mind. Not getting your coach solar prepped would be a huge mistake.

Solar prep is nothing more than running a positive and negative 6 AWG wire to your roof in addition to an ethernet cable run from your basement to your inverter control head inside the coach. These wires will be coiled and attached to a basement wall.

Why Solar

Solar is a battery charger, nothing more. When your RV is not powered by shore power the batteries are doing all of the work via your inverter and supplying the power as configured. Most of our motorhomes come with outstanding generators such as the ONAN QD8000 in my Newmar Ventana. These generators are often under utilized and will serve the needs to power your motorhome or RV in the event there is no shore power. Depending on the inverter controller you have there are various settings you can take advantage of as to when the generator comes on and how long it runs. The generator also serves as a battery charger but also works to supply electricity in the same way shore power does. So if we have these generators why would we ever want solar? There are benefits of solar such as not burning fuel to run a generator or making noise in a peaceful camping situation. Other scenarios include blending shore power with solar such as when I was recently at a 30 AMP campground I could use shore power to supply my air conditioners and solar to provide the source of power for all inverter supplied loads. An additional scenario is keeping your batteries charged when in storage or in for service. Advanced coaches these days have such high electrical loads then sitting in a service lot such as Cummins when not connected to shore power will kill your batteries if not disconnected and may damage your batteries requiring you to replace all of your house batteries which could be near half the cost of a solar install. Another scenario for solar which I'll be using in a few weeks is a long term stay at a campground that charges for electricity. I'll have my MH setup so that solar supplies all of my electrical demands until the batteries get to a certain percentage of charge and then shore power will come online if solar is not doing the job. So there are many reasons for solar and the amount of solar installed depends on your usage scenarios. If just keeping batteries charged while in storage you could require fewer panels such as just two panels on the roof. If you want to keep your refer on such as was one of my requirements for solar before I moved to a storage facility with shore power it was determined I needed a minimum of 1440W of solar.

What is involved in installing Solar

Believe it or not solar is not complicated. You can do it yourself as I did mine as long as you are educated and/or coached by someone else that has done it. You can have it professionally installed as well and I highly recommend AMSolar.com as they were very helpful at the time of my solar setup in determining minimum loads for my demands, what hardware to buy, etc. If you can get on your roof you can do this yourself, it's best to have someone help you even though I did mine solo. Getting the panels on the roof is the hardest part. As with everything these days YouTube is a great resource for learning something prior to doing it. Search YouTube for your topics of interest and get educated. AMSolar has great videos as well which I watched prior to my install.

Solar from top to bottom starts with the panels. You can get panels of various sizes based on your needs and available space. You'll want to design a layout so that you can still walk on your roof as needed. You can get solar panels from various supplies from AMSolar.com to Home Depot, etc. In fact you can get refurb or blemished ones from AMSolar I later learned when I needed two more and save quite a bit of money so don't hesitate to ask about that if you're okay with it. They still work the same but may have a scratch on the glass that prevents them from being sold as new. In the configuration @Chuggs designed to go against a MPPT type solar charger he designed the setup so that two solar panels were paired together to increase the voltage going to the solar charger effectively doubling it by putting the two panels in a series configuration. Each pair of panels then gets wired into what is called a combiner box which sits right on top of the area where your RV manufacturer left the ends of the wires underneath your roof. In the case of Newmar they put a metal plate over top of the area where the two wires should be. Keyword "should be". Cut carefully into the roof below this panel only large enough as needed to start looking for these wires. Don't go too deep either only cutting through the thickness needed to get through the roof material, there was a duct below my location. The two wires were about 6 inches offset from where Newmar indicated they would be, I then pulled them up and connected them to the combiner box. Each pair of panels is also connected to this combiner box and then you're essentially done on the roof after mounting the panels per the guidance of your solar coach or manufacturer. In my case it was simply a matter of cleaning the fiberglass with a mild abrasive scotchbrite pad, then 91% ISO alcohol, then adding 3M primer and using the adhesive mounts to attach to the fiberglass roof. You can also screw them down if needed but it's not necessary. Then add dicor around the mounts to keep the elements from breaking down the adhesive connection.

Now that the roof is done and the panels are attached to the roof and the wires are connected to the combiner box the power is now ready to be connected below. Obviously you want to protect the ends of your solar prep 6 AWG wires as you now have electricity flowing. I mounted all of my solar components to a board and then screwed the board to the sidewall of the basement. A mistake I made was the location of this install. I elected to install between the chassis rails and as I later got HWH Active Air installed it interfered with the location where the leveler sensor should have been mounted. With that said consider mounting your solar components near the basement door i.e. not between the chassis rails.

My coach has a Magnum 2812 inverter. Some choose to remain with Magnum components such as the PT100 but @Chuggs made a great decision to go with someone a little more cutting edge with bluetooth functionality, the ability to easily update the firmware, and an array of other components that all play well together. Per @Chuggs I went with a Victron Energy MPPT 150|100-tr solar charger. In the image below you can see this "blue box" but let's follow the flow of voltage. As you can see with the red arrow the positive from the roof is coming into a catastrophic fuse that will protect the components such as a voltage spike, lighting strike, etc. This cable then goes into the charge controller. The negative comes into the black power cutoff switch and into the charger controller allowing you to isolate (cutoff) the power flow from the roof panels if you need to such as doing some work on the solar charge controller or simply turning off your roof panels. The blue arrow indicates the flow which is going from the solar charge controller to the battery bank I believe using a 2 AWG cable and going through another cutoff switch to cut power to the charge controller and stop the flow to the battery bank. As you can see this is a very simple setup, nothing cosmic here, this is solar!

A few additional components are involved to improve the entire battery charging experience. As you can see in the photo below with the solar charge controller on the left side is a Magnum Battery Monitor Kit (ME-BMK) which measures the electricity flow through a shunt. Installing this shunt is a little complex in that you need to know how to install this carefully so as not to damage your inverter. Follow the instructions, research the web, or have a professional install it. The ME-BMK works well with the improved Magnum control head called the ME-ARC50 (A is for advanced, i.e. advanced controller) which works better with solar (PT100) and BMK components networked together. As some of us elected to go the Victron Energy path we opted to also add a battery monitor that the Victron system can use which is the BMV-712. The BMV shunt can be shared by the ME-BMK so you can have a single shunt in use that provides the information to the solar setup and also the Magnum control head. The BMV-712 also has a battery temperature sensor you can buy so the solar system can do automatic compensation based on battery temps such as in extreme hot or cold locations. Another item we added is the Venus GX which is a networking controller that provides data to the free Victron Energy Remote Management cloud portal (VRM). This allows you to view your solar data from anywhere using a computer or smartphone but also to configure alerts such as if your batteries go below a certain charge state, etc. You can also add a temperature sensor to the Venus GX to monitor items such as I use it to monitor my wet bay temperature and have alarms should the temp get below a certain point.

Conclusion

Solar is a great way to really learn the electrics of your RV/motorhome but also as described above to avoid being in situations where your batteries can be damaged by not being properly charged when out of your control. You'll better understand your house batteries and their capabilities, your inverter, and your shore power and how all this comes together to provide the needed electricity for your coaches demands. In addition if you decide to add MicroAir Soft Start units to your air conditioners as some of us have done and do a little more electrical work you can actually run an AC off of solar which is cool. That's for another discussion.

I've seen some great solar installs and learned so much from others on forums such as this. Several have even gone the lithium route and if you ever cross paths with @10 fan you should look at his lithium and solar setup where he installed two PT100 charge controllers and has both legs of his power supplied by solar allowing him to do anything that you can do with shore power. Amazing! Impressive install and design!

Feel free to ask any questions but again this is really designed to be an intro to solar with some usage scenarios but also not to be intimidated by solar as it can be a great asset to have on your RV. It is amazing how much power you can draw from the sun, with my 1800W setup (10 x 180W panels) I can easily sustain 100A of power from the roof which is the limit of my solar charge controller.

Victron Energy

Victron Energy - the professional choice for independent electric power

www.victronenergy.com

 

[Richpatty]

Hey Neal - This is a great start and gives a nice overview of what we went through as we did our installs very close together under the tutelage of Charlie (@Chuggs).

One thing I did differently, is I completed all of the basement work first... so when the panels came on line one set at a time, I could watch the controller "see the juice" coming off the roof and that allowed me to feel better about my connections. As I plugged in the panel pairs, I had my the Victron app on my phone and could see the system come alive. It was a good feeling as I had not done anything like this before either, so seeing success as I went along on the roof was nice. It also eliminates the issue of having hot panels with no connections. I put in the BMK first, then the controller and associated wires, then the combiner box...then the panels. Worked pretty well for me. Just a thought to others. Don't think there is a "wrong" way.

I am sure there are lots of chapters that could be written here...as folks can go in depth here with each component and I am sure that would be great to have as well. And you are correct that this is very do-able as I was able to do it - as have others- and not with much previous knowledge. YouTube is great - as well as the folks on the forums, as I would not have been able to do it without them.

Thanks.

 

[texskeet]

I am not a solar expert but I have learned a lot from others here mainly @Chuggs who guided me through my solar install which I mirrored his setup and then took it a few steps further. I wanted to share what I have learned to date as it may help others and I welcome others that also installed solar to add your opinions, correct me where necessary, and help to educate the RV community with where we are with solar as of this writing closing out 2019. These are only my opinions, it's okay if you don't agree, take from this what you want, discard what you don't want. I am writing this based on my knowledge of my coach brand - Newmar, others may vary.

Solar Prep

If you have the opportunity to order your coach you may be presented with an option to add solar prep. In my opinion everyone should add this option whether you intend to add solar or not. The next owner or owner after that may want to add solar and having these few wires run at build time will sure make adding solar an easier endeavor. At the time of ordering your coach you may have no plan to ever use solar and later change your mind. Not getting your coach solar prepped would be a huge mistake.

Solar prep is nothing more than running a positive and negative 6 AWG wire to your roof in addition to an ethernet cable run from your basement to your inverter control head inside the coach. These wires will be coiled and attached to a basement wall.

Why Solar

Solar is a battery charger, nothing more. When your RV is not powered by shore power the batteries are doing all of the work via your inverter and supplying the power as configured. Most of our motorhomes come with outstanding generators such as the ONAN QD8000 in my Newmar Ventana. These generators are often under utilized and will serve the needs to power your motorhome or RV in the event there is no shore power. Depending on the inverter controller you have there are various settings you can take advantage of as to when the generator comes on and how long it runs. The generator also serves as a battery charger but also works to supply electricity in the same way shore power does. So if we have these generators why would we ever want solar? There are benefits of solar such as not burning fuel to run a generator or making noise in a peaceful camping situation. Other scenarios include blending shore power with solar such as when I was recently at a 30 AMP campground I could use shore power to supply my air conditioners and solar to provide the source of power for all inverter supplied loads. An additional scenario is keeping your batteries charged when in storage or in for service. Advanced coaches these days have such high electrical loads then sitting in a service lot such as Cummins when not connected to shore power will kill your batteries if not disconnected and may damage your batteries requiring you to replace all of your house batteries which could be near half the cost of a solar install. Another scenario for solar which I'll be using in a few weeks is a long term stay at a campground that charges for electricity. I'll have my MH setup so that solar supplies all of my electrical demands until the batteries get to a certain percentage of charge and then shore power will come online if solar is not doing the job. So there are many reasons for solar and the amount of solar installed depends on your usage scenarios. If just keeping batteries charged while in storage you could require fewer panels such as just two panels on the roof. If you want to keep your refer on such as was one of my requirements for solar before I moved to a storage facility with shore power it was determined I needed a minimum of 1440W of solar.

What is involved in installing Solar

Believe it or not solar is not complicated. You can do it yourself as I did mine as long as you are educated and/or coached by someone else that has done it. You can have it professionally installed as well and I highly recommend AMSolar.com as they were very helpful at the time of my solar setup in determining minimum loads for my demands, what hardware to buy, etc. If you can get on your roof you can do this yourself, it's best to have someone help you even though I did mine solo. Getting the panels on the roof is the hardest part. As with everything these days YouTube is a great resource for learning something prior to doing it. Search YouTube for your topics of interest and get educated. AMSolar has great videos as well which I watched prior to my install.

Solar from top to bottom starts with the panels. You can get panels of various sizes based on your needs and available space. You'll want to design a layout so that you can still walk on your roof as needed. You can get solar panels from various supplies from AMSolar.com to Home Depot, etc. In fact you can get refurb or blemished ones from AMSolar I later learned when I needed two more and save quite a bit of money so don't hesitate to ask about that if you're okay with it. They still work the same but may have a scratch on the glass that prevents them from being sold as new. In the configuration @Chuggs designed to go against a MPPT type solar charger he designed the setup so that two solar panels were paired together to increase the voltage going to the solar charger effectively doubling it by putting the two panels in a series configuration. Each pair of panels then gets wired into what is called a combiner box which sits right on top of the area where your RV manufacturer left the ends of the wires underneath your roof. In the case of Newmar they put a metal plate over top of the area where the two wires should be. Keyword "should be". Cut carefully into the roof below this panel only large enough as needed to start looking for these wires. Don't go too deep either only cutting through the thickness needed to get through the roof material, there was a duct below my location. The two wires were about 6 inches offset from where Newmar indicated they would be, I then pulled them up and connected them to the combiner box. Each pair of panels is also connected to this combiner box and then you're essentially done on the roof after mounting the panels per the guidance of your solar coach or manufacturer. In my case it was simply a matter of cleaning the fiberglass with a mild abrasive scotchbrite pad, then 91% ISO alcohol, then adding 3M primer and using the adhesive mounts to attach to the fiberglass roof. You can also screw them down if needed but it's not necessary. Then add dicor around the mounts to keep the elements from breaking down the adhesive connection.

Now that the roof is done and the panels are attached to the roof and the wires are connected to the combiner box the power is now ready to be connected below. Obviously you want to protect the ends of your solar prep 6 AWG wires as you now have electricity flowing. I mounted all of my solar components to a board and then screwed the board to the sidewall of the basement. A mistake I made was the location of this install. I elected to install between the chassis rails and as I later got HWH Active Air installed it interfered with the location where the leveler sensor should have been mounted. With that said consider mounting your solar components near the basement door i.e. not between the chassis rails.

My coach has a Magnum 2812 inverter. Some choose to remain with Magnum components such as the PT100 but @Chuggs made a great decision to go with someone a little more cutting edge with bluetooth functionality, the ability to easily update the firmware, and an array of other components that all play well together. Per @Chuggs I went with a Victron Energy MPPT 150|100-tr solar charger. In the image below you can see this "blue box" but let's follow the flow of voltage. As you can see with the red arrow the positive from the roof is coming into a catastrophic fuse that will protect the components such as a voltage spike, lighting strike, etc. This cable then goes into the charge controller. The negative comes into the black power cutoff switch and into the charger controller allowing you to isolate (cutoff) the power flow from the roof panels if you need to such as doing some work on the solar charge controller or simply turning off your roof panels. The blue arrow indicates the flow which is going from the solar charge controller to the battery bank I believe using a 2 AWG cable and going through another cutoff switch to cut power to the charge controller and stop the flow to the battery bank. As you can see this is a very simple setup, nothing cosmic here, this is solar!

A few additional components are involved to improve the entire battery charging experience. As you can see in the photo below with the solar charge controller on the left side is a Magnum Battery Monitor Kit (ME-BMK) which measures the electricity flow through a shunt. Installing this shunt is a little complex in that you need to know how to install this carefully so as not to damage your inverter. Follow the instructions, research the web, or have a professional install it. The ME-BMK works well with the improved Magnum control head called the ME-ARC50 (A is for advanced, i.e. advanced controller) which works better with solar (PT100) and BMK components networked together. As some of us elected to go the Victron Energy path we opted to also add a battery monitor that the Victron system can use which is the BMV-712. The BMV shunt can be shared by the ME-BMK so you can have a single shunt in use that provides the information to the solar setup and also the Magnum control head. The BMV-712 also has a battery temperature sensor you can buy so the solar system can do automatic compensation based on battery temps such as in extreme hot or cold locations. Another item we added is the Venus GX which is a networking controller that provides data to the free Victron Energy Remote Management cloud portal (VRM). This allows you to view your solar data from anywhere using a computer or smartphone but also to configure alerts such as if your batteries go below a certain charge state, etc. You can also add a temperature sensor to the Venus GX to monitor items such as I use it to monitor my wet bay temperature and have alarms should the temp get below a certain point.

View attachment 642

View attachment 641​

Conclusion

Solar is a great way to really learn the electrics of your RV/motorhome but also as described above to avoid being in situations where your batteries can be damaged by not being properly charged when out of your control. You'll better understand your house batteries and their capabilities, your inverter, and your shore power and how all this comes together to provide the needed electricity for your coaches demands. In addition if you decide to add MicroAir Soft Start units to your air conditioners as some of us have done and do a little more electrical work you can actually run an AC off of solar which is cool. That's for another discussion.

I've seen some great solar installs and learned so much from others on forums such as this. Several have even gone the lithium route and if you ever cross paths with @10 fan you should look at his lithium and solar setup where he installed two PT100 charge controllers and has both legs of his power supplied by solar allowing him to do anything that you can do with shore power. Amazing! Impressive install and design!

Feel free to ask any questions but again this is really designed to be an intro to solar with some usage scenarios but also not to be intimidated by solar as it can be a great asset to have on your RV. It is amazing how much power you can draw from the sun, with my 1800W setup (10 x 180W panels) I can easily sustain 100A of power from the roof which is the limit of my solar charge controller.

Victron Energy

Victron Energy - the professional choice for independent electric power

www.victronenergy.com

Neal have one thing you should change. The solar Off-On switch should after the solar and before the solar charger. The panels can be turned off with no harm but charger can be hurt.

 

[texskeet]

I need some help on one thing. I put soft start on my ac unit but when I try to power it off the batteries I get E7 on my ac control . It goes off real quick then the hour glass comes back on and when it is finished it timing the E7 comes back and so on.

 

[Neal]

Neal have one thing you should change. The solar Off-On switch should after the solar and before the solar charger. The panels can be turned off with no harm but charger can be hurt.

The black on/off is the cutoff between panels and charger. The red on/off is the cutoff between charger and batteries. Correct me if I'm wrong Professor @Chuggs

 

[Neal]

I need some help on one thing. I put soft start on my ac unit but when I try to power it off the batteries I get E7 on my ac control . It goes off real quick then the hour glass comes back on and when it is finished it timing the E7 comes back and so on.

First step is soft start on AC units. Second step is a bit of a complex wiring change in the circuit breaker panel @Chuggs architected. Essentially we have a 3 way switch in that area now that tells AC1 to get power from either shore power or inverter. The 3 way switch essentially is a "shore power" | "off" | "inverter power" switch. So when we want to power the front AC off of batteries we need to change the switch position. It involves adding a circuit breaker so essentially there are two paths for AC1 (front AC): shore power side (left) or inverter power side (right) as mine is left right, I've seen Dutch Stars with a vertical orientation where the inverter breakers are at the bottom (and also shaded gray on the labels).

 

[Chuggs]

The black on/off is the cutoff between panels and charger. The red on/off is the cutoff between charger and batteries. Correct me if I'm wrong Professor @Chuggs

You are 100% correct...

I decided to make the switches different colors in case I had to describe to someone over the phon...the steps to deactivate the system. Top switch, black...is the PV side on/off...Bottom switch, red...is the Battery Side on/off.

 

[Chuggs]

First step is soft start on AC units. Second step is a bit of a complex wiring change in the circuit breaker panel @Chuggs architected. Essentially we have a 3 way switch in that area now that tells AC1 to get power from either shore power or inverter. The 3 way switch essentially is a "shore power" | "off" | "inverter power" switch. So when we want to power the front AC off of batteries we need to change the switch position. It involves adding a circuit breaker so essentially there are two paths for AC1 (front AC): shore power side (left) or inverter power side (right) as mine is left right, I've seen Dutch Stars with a vertical orientation where the inverter breakers are at the bottom (and also shaded gray on the labels).

I gave Neal some of my ugly drawings...and told him exactly what to buy. Problem is...the breaker that should have worked didn’t...and Neal drove all over Timbuktu getting a breaker that would work. He saved me a lot of time when I went to install mine...he had already ironed out the roadblocks

 

[Neal]

I forgot about the breakers, for those that don't know Newmar uses two different types of breakers, very very slightly different, for the shore power side vs. inverter side, not sure why. If you look at the front of the breaker you can see the type and that's what you would need to get whether shore power or inverter sides.

 

[Joe Hogan]

We have a similar solar setup but with an upgraded Magnum Inverter, 3000 watt Hybrid. The hybrid will allow the batteries provide supplemental power should the shore or generator need help with a load.
We have 1260 watts of solar, theoretically, on the roof. Eight panels in series. Generates 75~90 volts on a sunny day. We used the higher voltage to reduce current (amps) over the Solar Prep wiring coming from the roof. So far we see as much as 1100 watts during a sunny day. At summer solstice it can be higher and winter lower.
I have been struggling with the BMV 712 to get correct readings. The 712 seems to think the battery bank is 300 amps not 600 amps. Changed settings on the 712 and reset it a couple of times but just can't get it to read correctly. I think I'll relocate it closer to the shunt to see if that helps.

 

[Woodsie8*]

Silly question, but I see people with pirtable panels at RV parks, they move around on the ground to face the sun. Can I just get one, with battery connections and hook to house battery to charge the battery? I obviously know nothing about it, but we can hook a battery charger to it and charge it like that.

 

[kangarooelaine]

My question is how long does install take? what is the average install time for pros? for random owners?

Second, my thought was dividing it into two processes:
1. install inverter and extra battery to use with portable solar panel
2. install roof panels and more batteries
Does that sound reasonable?
My thought was that I want to be able to take out the RV for a weekend and use some solar for extra power. If all goes well and we enjoy this a lot then maybe install more so we can do longer trips without plugging in. This would be to save costs (as well as reduce weight short term since more panels and batteries add weight).

Our RV is a Minnie Winnie 22R with an Onan generator 4000. It is NOT 'solar ready.' We live in the SW where it can get VERY hot in Summer. Even at night. We try to escape the heat by traveling in Summer, but there will be times where we just need to run that a/c for a whole day or weekend, maybe longer.

Silly question, but I see people with pirtable panels at RV parks, they move around on the ground to face the sun. Can I just get one, with battery connections and hook to house battery to charge the battery? I obviously know nothing about it, but we can hook a battery charger to it and charge it like that.

I'm no expert and haven't done anything with solar but I've been reading. From what I've read, those people have RVs that have 'solar prep' and so they can just plug those portable solar panels into their RV to add some power. It's not as much power as a roof full of panels though and can obviously only generate power when parked and the panel is set up (not on the road or in storage).

 

[Neal]

How long does it take? Depends on what is being done. For me which was initially 8 panels on the roof, done by myself. 1 day (a RV day is a few hours of course, not 8-10 typically) was the basement work installing the solar controller and wiring to the battery. Essentially built it on a board on the picnic table then mounted the board and connected the wires. Next step was placing and securing the panels. Final step was the wiring. Then back for cleanup including tie downs, dicor around the solar panel mounts to keep moisture and yuck out of the adhesive area. I'd say 3 "RV" days minimum if you break it into the phases. More or less based on the level of the job such as replacing batteries, inverter, etc. In the end, give it a week whether self or professionally.

 

[flyboy013]

Thanks for the writeup and the offer to answer questions. Here are my initial questions:

While I think I’m competent enough to do the install myself, I’m interested in taking the coach somewhere and just having it done in a day or so. I reached out to AM Solar, but given that they are on the West Coast and we haven’t made it out that way yet due to having other commitments that limits the time we have to travel that far at our slow pace, I’m wondering if you’ve found any competent RV Solar companies in Virginia or surrounding states?

Newmar’s solar prep includes a blue cable with RJ45 connectors that goes from the basement to the cabinet above the driver. Did this cable get used?

Related to the above question, does the MPPT have a remote monitoring capability that would be installed inside the coach?

I noticed that the MPPT has a LED indicting which charging mode (ie. bulk, absorb, float) it is in. Does the MPPT get this info from the inverter/charger so that it can adjust the output voltage accordingly?

Is there such a thing as installing too much solar capability? It would seem that it would be cheapest to install the most panels at the time that the initial installation was being done. Is there a downside?

 

[Kevin D Pem]

Silly question, but I see people with pirtable panels at RV parks, they move around on the ground to face the sun. Can I just get one, with battery connections and hook to house battery to charge the battery? I obviously know nothing about it, but we can hook a battery charger to it and charge it like that.

Hi @Woodsie8* Some things you should know. There are only two types of solar panels. Those that are bolted down and broken ones. The difference is one gust of wind. Second thing you should know. Solar controllers save batteries and should be considered a necessary part of the package. two types are available PWM(not great) and MPPT controllers. MPPT stands for maximum Power Point Tracking. The idea is panels produce their highest power level at only one point on the output scale and the controller is designed to find and maintain that point. Don't think that a charge controller need break the bank. My charge controllers are MPPT controllers the last one a 60 amp controller from Amazon cost me 100 dollars with shipping. I use a different controller for panels (individually or strings) because different angles or shading will bring down that string. I am inclined to use flexible panels where I can for weight reasons. But for my setup I need the frame so use house panels (250 watt 60 cell panels). If you want to run the panels in series have fun. When voltages are more than 2.5 times the battery voltage, efficiency of the controller goes down. can't get around it, it is the nature of the buck converter. (DC to DC converter) question this, look up buck converter data and design data for them. A point here. with only small losses in output you can use a buck converter as a solar controller, I know I have done it. They work better when lithium is used and the voltage drops to low they will self start because they never shut down. You only need enough batteries to get through the night, or if you have the space 4 days of cloud cover. That depends on your usage, and enough solar to supply power enough to keep up with demand and trickle charge the bank. You can never have to much solar, I repeat what I hear like a record. I happen to believe it though, would like to aquire another 500watts because I can make them fit on the roof, already have 1000 watts, and a 280 watt panel I see no way of putting on the roof.
Another point: this is important. MPPT controllers choose what voltage to run at with the battery bank hooked up. This means the battery should be the first thing connected and the last thing disconnected. They have been known to self destruct when this order is not used. For solid connections air gap breakers should be used for both battery connections and solar panel connections.

 

[Woodsie8*]

Ih my gosh! Thanks for the info! I have a 20’ rig, not a lot of room up there. The roof is difficult to clean, as it is. I could out hinges in frame to lift. I live in the forest and I just know a branch or heavy limb will land in it. Thoughts?

 

[Kevin D Pem]

My 26ft fifth has a 20ft box the rest over the hitch. I have 1000w over the box only. I look for spots in the forest that are clear of trees. I don't park under the shade of trees, what is the point if solar is the game.

 

[Chuggs]

Thanks for the writeup and the offer to answer questions. Here are my initial questions:

While I think I’m competent enough to do the install myself, I’m interested in taking the coach somewhere and just having it done in a day or so. I reached out to AM Solar, but given that they are on the West Coast and we haven’t made it out that way yet due to having other commitments that limits the time we have to travel that far at our slow pace, I’m wondering if you’ve found any competent RV Solar companies in Virginia or surrounding states?

Newmar’s solar prep includes a blue cable with RJ45 connectors that goes from the basement to the cabinet above the driver. Did this cable get used?

Related to the above question, does the MPPT have a remote monitoring capability that would be installed inside the coach?

I noticed that the MPPT has a LED indicting which charging mode (ie. bulk, absorb, float) it is in. Does the MPPT get this info from the inverter/charger so that it can adjust the output voltage accordingly?

Is there such a thing as installing too much solar capability? It would seem that it would be cheapest to install the most panels at the time that the initial installation was being done. Is there a downside?

Let’s start last question first. Not really. A solar panel, when exposed to sunlight is like having a battery. More solar panels equals more batteries. Aside from cost and weight...there is no downside to having MORE. You aren’t likely to fit so many on an RV that you will hear anyone say...”I think I have too much.” Never heard anyone say that, yet.

The solar charge controller is Independent of the Inverter/Charger. Well...if you have a Magnum MS inverter and add a Magnum PT-100...they do talk to a common remote...and share settings. But think of the Solar MPPT controller as an independent thinking device. It looks at battery voltage and charges accordingly. If there is something already charging, when the controller wakes up at daybreak...it may idle in Float mode...and let the other charger go at it. If it wakes to less voltage...it will go thru BULK, ABSORB, and FLOAT, which may cause the other charger to idle in FLOAT, Standby, Silent, etc...as it’s programming is set. If you apply a large load...and both chargers see a dip in voltage...they may both hit the party by going back to BULK at the same time. You really don’t have to worry about it too much. It all happens automatically, once set for the correct charge parameters.

Some inexpensive controllers are stand alone. And you have to see the settings/readings on the unit. Others have a remote panel display. The option many take is the Victron SmartSolar series. It has built-in Bluetooth... You download the free Victron Connect app for your device...pair the two...and now you have a very intuitive display. You set, control, monitor, and even update firmware....all from your phone or tablet. I don’t want to put the cart too far ahead of the horse...but Victron devices can also be linked a few different ways. VE.direct is a proprietary cable. If you connect your Solar Controller to a GX device by VE.direct cable...such as Venus GX or Cerbo GX...and you have the GX connected wirelessly/or wired to an internet router/hub. You now have the ability to monitor and manage your solar from anywhere in the world, it is called VRM or Victron Remote Management. If you have your rig stored somewhere else...it sure is nice to be able to check in. It can also be set to give you email alerts to any condition you care to be alerted to. I monitor mine mainly from the VRM portal...and have an iPAD mini mounted to my A-pillar and can see the display while driving. More for fun...or running high loads like an AC unit.

You can add a remote to the cabinet with the solar option RJ cord...but if you go with Victron SmartSolar...it’s kinda a big step backward. The Victron app is easier to read, interpret, and control. A remote display means you have to stand and bend your neck. Reach up. Cycle thru multiple tiny display pages...and toggle up/down repeatedly to adjust settings. After using Victron Connect...the remote will feel like the stone ages.

I understand that having someone else do it adds convenience. If you have all the parts and tools...good weather...and assistant...you can knock the job out in two days. One day on the roof...mounting panels, running wires, adding combiner box, and connecting to the solar prep.
The other day is spent in the basement...mounting switches, breakers, controller, wires, fuse...and battery terminations. Actually, doing the basement first is better...because you will not Have to worry about loose ends when you start applying solar PV energy. It isn’t a difficult task. There are positive and negative wires...you’ll have to cut, strip, and crimp terminations on wires...apply colored heat shrink for a neat job. From the mounts (I used AMSolar) to the wire terminations...there are step by step video instructions on AMSolars website or YouTube. Beside saving yourself a lot of labor expense...having a first hand knowledge of your system will pay dividends. Instead of having a system plopped into your lap...you’ll have most likely read and reread the manuals before and during installation. When done...you actually know what the readings are telling you. If something isn’t up to par...you know where stuff is and where to look for connections, components. There will be no mystery. I‘m not recommending anyone get up on the roof, if it isn’t something they feel safe doing. You have to be careful. It can expose you to a fall hazard. So, please don’t bite off more than you are comfortable with...just because I promote self-installation. Only you know if this falls within your personal comfort zone.

Most of us joke...after installing the system ourselves we say...”Now I know why it’s so expensive to have one installed”. You’ll get a workout...no doubt. But, it is a rewarding experience and really gives you a detailed insight into the working of your system.

Sorry for being long winded. Ask questions...we all did...as the first thing you build is the system in your mind. After you get it built completely in your mind...you will be able to build the physical system on your coach.

 

[Chuggs]

BTW...the “Victron Connect” App is free...and you can launch it in simulation mode. Select the type of solar controller you would like to view and you can become familiar with the settings and options without even purchasing a charge controller. All of the Victron manuals are available free online as well. I reviewed the manuals for both of the charge controllers I was considering before purchasing. The Manual for the Magnum PT-100 has some excellent worksheets for determining amp rating for breakers and wiring. I recommend downloading it even if you do not purchase a PT-100 solar charge controller.

The Victron controller I have is the Victron SmartSolar MPPT150/100-TR... As the name implies...it can handle 150v PV input...and it will output up to 100A of charge.

 

[flyboy013]

Charlie - Thanks for the detailed response. It really helps in understanding the capability, especially the part about the MPPT being a charger and the coach’s two chargers (MPPT and Xantrex SW3012) working in parallel. I hadn’t thought of it that way.

I previously purchased a BMV-712, but haven’t yet installed it. I had looked at connecting it to my SmartHome capability via a VE.Direct RS232 cable so that I can remotely monitor its data in addition to all the stuff available on the RV-C network. I’ll probably continue to look into this and include the MPPT as well. I prefer having control of my own data/system instead of relying on a cloud service, but will utilize a cloud service when it’s best to do so.

As I get older, getting on roofs is not something I look forward to. Especially the transition from the ladder to roof and vice versa. I just remembered that my brother recently purchased on of those scissor jack lifts like they have at the Newmar Service Center. That would definitely make the install more comfortable, thus perhaps I can do the install myself.

I understand that the solar prep includes two 6 AWG (?) wires to take the solar panel power to the basement installed MPPT. I understand that there is a limit as to how many amps can flow over the wire and the solution to providing more solar power watts to the MPPT is to increase the voltage begin carried over the wire either by using higher voltage panels or by connecting several panels in series (similar to how the coach’s 6V batteries are wired). Do I understand this correctly? Is there an ideal voltage? I assume the limitation will be based on the MPPT input voltage capabilities?

Thanks