Affordable Solar -- How To Design and Install an Affordable Solar System

[SolarPoweredRV]

Because operating an Air Conditioner while Boondocking is so important to many of us who have installed (or are going to install) Solar and battery systems, I have provided a link to a thread discussing Lippert's new "Inverter style" Air Conditioner.

Here are the highlights:

Finally, Finally, somebody comes out with an energy efficient Air Conditioner for RVs!!!

> 40% more efficient.
> Variable Speed motor(s).
> Does not require a "Soft Start".
> Smaller 8k BTU model for bedrooms and smaller RVs.
> Higher 18k BTU rated unit to cool larger spaces.

If you have a Solar system, or are even thinking about getting a Solar system, this new "Inverter style" Air Conditioner could allow RVers to finally be able to use their Air Conditioners while Boondocking without needing a "Robust" Solar and battery install. You could get by with a more "Modest" Solar and battery system installation and still be able to run your Air Conditioner while Boondocking, or overnight when you are traveling.

This Air Conditioner is also so efficient that it does not require a "Soft Start" to allow you to run it from a smaller battery bank.

Having this Air Conditioner(s) installed on your RV will also allow you to carry a smaller, more efficient, Generator when you Boondock.

While they did not mention that this new A/C unit could also provide heat, it seems logical that it would, given that it is an all new design based on the "Inverter" style "Mini Split" units available for residential use.

If you would like to view a video with the Lippert Executives demonstrating the features of this new Air Conditioning system:

Lippert Executives Introduce New, 40% more Efficient, Air Conditioner for RVs

If you would like to read and follow the thread discussing this new Air Conditioner:

MyGrandrv.com/forum/New Inverter Air Conditioner

[Scott'n'Wendy]

This is very much related to your thread here but a different concern than most of you 'southerners' would have. What if you have the potential for snow buildup on your roof? I have been looking at possibly adding a modest solar system and see the panels are rated for X amount of load. But those panels are mounted with four brackets that have a very small foot print on the roof....which would put a very high load on the roof at those four points I would think. Is this a legitimate concern?

[SolarPoweredRV]

This is very much related to your thread here but a different concern than most of you 'southerners' would have. What if you have the potential for snow buildup on your roof? I have been looking at possibly adding a modest solar system and see the panels are rated for X amount of load. But those panels are mounted with four brackets that have a very small foot print on the roof....which would put a very high load on the roof at those four points I would think. Is this a legitimate concern?

There are a couple of ways to address this issue:

First, you could perform some Snow Load calculations based on the actual footprint (approx. 2 inch by 4 inch) of the mounting brackets you plan to use and determine if they exceed the compressive capacity of 3/8 inch OSB.

The other thing you can do (and this is the route I would take) is to "beef up" your installation.

I would install 6 brackets (presuming use of the popular "Z" style brackets) on each panel. I would also install a 6 inch by 6 inch piece of 1/4 or 3/8 inch plywood under each mounting point to spread the weight across a larger roof area. I would first waterproof the plywood with either paint, or spray on truck bed liner (my preferred method). Then, I would attach the wood to the roof using sealant and cover the wood with EternaBond tape, thereby, encapsulating the wood and waterproofing it before I mounted the Solar panel on top.

Note: I used this method of installing wood (shims in my case) under the mounting bracket and encapsulating it in EternaBond tape on the four corner brackets of my transverse mounted Solar, panel right behind the front cap. Because the roof is curved, and I used 6 brackets per panel, I needed to build up the area under each corner to accommodate the curvature of the roof.

[Lance Glogowsky]

There are a couple of ways to address this issue:

First, you could perform some Snow Load calculations based on the actual footprint (approx. 2 inch by 4 inch) of the mounting brackets you plan to use and determine if they exceed the compressive capacity of 3/8 inch OSB.

The other thing you can do (and this is the route I would take) is to "beef up" your installation.

I would install 6 brackets (presuming use of the popular "Z" style brackets) on each panel. I would also install a 6 inch by 6 inch piece of 1/4 or 3/8 inch plywood under each mounting point to spread the weight across a larger roof area. I would first waterproof the plywood with either paint, or spray on truck bed liner (my preferred method). Then, I would attach the wood to the roof using sealant and cover the wood with EternaBond tape, thereby, encapsulating the wood and waterproofing it before I mounted the Solar panel on top.

Note: I used this method of installing wood (shims in my case) under the mounting bracket and encapsulating it in EternaBond tape on the four corner brackets of my transverse mounted Solar, panel right behind the front cap. Because the roof is curved, and I used 6 brackets per panel, I needed to build up the area under each corner to accommodate the curvature of the roof.

Dave

Hope you don't mind me jumping in here since I'm ready to take the Solar system plunge and have learn a lot reading your threads. Just want to get your thoughts.
I want to go with the Multi Plus II with the needed Victron accessories needed for it. I already have 4 Safari Lithium 12 volt batteries. I'm wavering on the type and size of solar panels. Our power usage includes 2 nightly cpaps, my DW's morning hair dryer and curling iron, maybe 4 hours of daily TV/DVD playing, and maybe 30 minutes of microwave usage. supplementing with our two 2200 watt generators if needed, especially for the AC. We boondock about 2 to 21/2 months a year, in 2 week cycles. I know you recommend residential panels. I believe you have 325 watt panels. Would three be sufficient in my power usage. I couldn't find any on amazon and looking around. I'm assuming I could use non-residential panels but would need more to come up with the same wattage and would take up more room. I still don't understand when you would connect them in series compared to parallel. Thanks for any insight.

Lance

[SolarPoweredRV]

Dave

Hope you don't mind me jumping in here since I'm ready to take the Solar system plunge and have learn a lot reading your threads. Just want to get your thoughts.
I want to go with the Multi Plus II with the needed Victron accessories needed for it. I already have 4 Safari Lithium 12 volt batteries. I'm wavering on the type and size of solar panels. Our power usage includes 2 nightly cpaps, my DW's morning hair dryer and curling iron, maybe 4 hours of daily TV/DVD playing, and maybe 30 minutes of microwave usage. supplementing with our two 2200 watt generators if needed, especially for the AC. We boondock about 2 to 21/2 months a year, in 2 week cycles. I know you recommend residential panels. I believe you have 325 watt panels. Would three be sufficient in my power usage. I couldn't find any on amazon and looking around. I'm assuming I could use non-residential panels but would need more to come up with the same wattage and would take up more room. I still don't understand when you would connect them in series compared to parallel. Thanks for any insight.

Lance

The answers all revolve around the voltage of your Solar panels...

You didn't say, but I assume you will be installing a 12 volt battery bank instead of a 24 volt battery bank.

A secondary reason I recommend using Residential Solar panels, besides the higher Watts per dollar (and square foot), is because they operate at a higher voltage. The usual (12 volt) brands used on RVs operate around 18 volts. Your battery voltage will be about 14.2 volts when fully charged. When the Sun hits your Solar panels, they only generate their "full voltage" when the Sun is shining directly on them (in the case of being flat mounted on an RV roof, from 11am to 1pm), otherwise, the Solar panels generate partial voltage. With 18v panels and needing ~14.2 volts to charge your batteries, you only have 3.8 volts differentiation to allow for cloudy days or shaded panels. In other words, you would only be charging during a small portion of the day when your panels are generating above the 14.2 volts your batteries need.

To address this voltage issue, you can install higher voltage panels, or install the panels in "Series" which will "add" the voltage together for each panel, i.e.: 18, 36, 54...

Keeping the above explanation in mind, if you are using higher voltage panels, say 39 volts, you might not want to string your panels in "Series" because your voltage would be too high for your Solar Charge Controller to handle, i.e.: 117 volts for three panels. This is why panels are often installed in both Series and Parallel (keep in mind you need an even number of panels to install in Series/Parallel).

Additionally, you need to consider the effects of shading on your panels. In a series configuration, if you get shading on one panel, the voltage for the whole string can be reduced, whereas, if the panels are wired in Parallel, only the panel with the shade would be effected.

You need to evaluate all of the above issues when deciding on which Solar panels to purchase and how they will be wired on the roof.

Also keep in mind that the voltage and amperage of your Solar panels will dictate which Solar Charge Controller you will need to buy.

Note: often, wiring your panels in Series/Parallel will give you the best results.

Note 2: to give yourself more Solar panel options, simply perform a Google search for the Solar panel wattage you are interested in. Look at the panel dimensions to determine if they will physically fit on your roof. Keep in mind that the lower wattage panels (275 - 325) will be smaller in size compared to the 450+ Watt panels. If you could fit two 450 Watt panels, you might be better off than getting 4 - 275 Watt panels because of the ease of mounting only two panels on the roof.

Note 3: I would recommend sizing your Solar panel Wattage to be about 2 to 2.5 times the amp hour rating of your battery bank, i.e.: 400ah battery bank, 800 to 1,000 Watts of Solar.

Note 4: when looking at Solar panels, make a cardboard cut-out of the Solar panels you are considering and get on your roof to plan their placement (be sure to include the mounting brackets in your cardboard dimensions).

[huntindog]

The answers all revolve around the voltage of your Solar panels...

You didn't say, but I assume you will be installing a 12 volt battery bank instead of a 24 volt battery bank.

A secondary reason I recommend using Residential Solar panels, besides the higher Watts per dollar (and square foot), is because they operate at a higher voltage. The usual (12 volt) brands used on RVs operate around 18 volts. Your battery voltage will be about 14.2 volts when fully charged. When the Sun hits your Solar panels, they only generate their "full voltage" when the Sun is shining directly on them (in the case of being flat mounted on an RV roof, from 11am to 1pm), otherwise, the Solar panels generate partial voltage. With 18v panels and needing ~14.2 volts to charge your batteries, you only have 3.8 volts differentiation to allow for cloudy days or shaded panels. In other words, you would only be charging during a small portion of the day when your panels are generating above the 14.2 volts your batteries need.

To address this voltage issue, you can install higher voltage panels, or install the panels in "Series" which will "add" the voltage together for each panel, i.e.: 18, 36, 54...

Keeping the above explanation in mind, if you are using higher voltage panels, say 39 volts, you might not want to string your panels in "Series" because your voltage would be too high for your Solar Charge Controller to handle, i.e.: 117 volts for three panels. This is why panels are often installed in both Series and Parallel (keep in mind you need an even number of panels to install in Series/Parallel).

Additionally, you need to consider the effects of shading on your panels. In a series configuration, if you get shading on one panel, the voltage for the whole string can be reduced, whereas, if the panels are wired in Parallel, only the panel with the shade would be effected.

You need to evaluate all of the above issues when deciding on which Solar panels to purchase and how they will be wired on the roof.

Also keep in mind that the voltage and amperage of your Solar panels will dictate which Solar Charge Controller you will need to buy.

Note: often, wiring your panels in Series/Parallel will give you the best results.

Note 2: to give yourself more Solar panel options, simply perform a Google search for the Solar panel wattage you are interested in. Look at the panel dimensions to determine if they will physically fit on your roof. Keep in mind that the lower wattage panels (275 - 325) will be smaller in size compared to the 450+ Watt panels. If you could fit two 450 Watt panels, you might be better off than getting 4 - 275 Watt panels because of the ease of mounting only two panels on the roof.

Note 3: I would recommend sizing your Solar panel Wattage to be about 2 to 2.5 times the amp hour rating of your battery bank, i.e.: 400ah battery bank, 800 to 1,000 Watts of Solar.

Note 4: when looking at Solar panels, make a cardboard cut-out of the Solar panels you are considering and get on your roof to plan their placement (be sure to include the mounting brackets in your cardboard dimensions).

As a dedicated boondocker, we never know just how our solar will be situated. For that reason, I am not a fan of the larger panels for RVs. I have many panels distributed across the entire roof, leaving enough room to be able to perform maintainence up there (another reason for smaller panels) So no matter how our camp ends up, our system will harvest a fair amount of energy
IMO, the reason residential panels are larger is because it makes sense for a residential install. A house never moves, so it's solar position once fixed will stay the same and houses need a LOT more wattage than an RV. They are cheaper per watt because so many are produced for houses, that economy of scale makes them cheaper to produce.

[Conner58]

We use portable panels with roof mounted. The portable ones provide more power on alot of days . Being able to get sun early, angle and rotate makes a huge difference.

[huntindog]

We use portable panels with roof mounted. The portable ones provide more power on alot of days . Being able to get sun early, angle and rotate makes a huge difference.

I have considered this. Figured I would likely end up with a busted panel, plus I don't sit around camp enough to baby sit them, and my present configuration is working quite well.

[robmcqueen]

Dave

Hope you don't mind me jumping in here since I'm ready to take the Solar system plunge and have learn a lot reading your threads. Just want to get your thoughts.
I want to go with the Multi Plus II with the needed Victron accessories needed for it. I already have 4 Safari Lithium 12 volt batteries. I'm wavering on the type and size of solar panels. Our power usage includes 2 nightly cpaps, my DW's morning hair dryer and curling iron, maybe 4 hours of daily TV/DVD playing, and maybe 30 minutes of microwave usage. supplementing with our two 2200 watt generators if needed, especially for the AC. We boondock about 2 to 21/2 months a year, in 2 week cycles. I know you recommend residential panels. I believe you have 325 watt panels. Would three be sufficient in my power usage. I couldn't find any on amazon and looking around. I'm assuming I could use non-residential panels but would need more to come up with the same wattage and would take up more room. I still don't understand when you would connect them in series compared to parallel. Thanks for any insight.

Lance

This show how to connect the panels.
https://explorist.life/using-mismatc...r-panel-sizes/

[Lance Glogowsky]

Everyone:
Thanks for the help and thoughts. It seems if you have the roof room without interfering with roof maintenance and safety, residential panels might be the way to go.
Still working on a lot of questions. I still have a lack of understanding when it comes to connecting panels in series v. parallel or both, dealing with voltage and amperage. Studying robmcqueen's link regarding connecting panels in series or parallel, the ending result is still the same with the same amount of wattage going into the solar charger, using the example in the link. It seems like parallel would be the best overall so if one panel goes bad or in the shade, the others are still doing their job over series. Besides for wattage, does different panels have different voltage output? I'm assuming you determine the solar charger you need after figuring out your panel setup? I'm trying to understand the numbers relationship on the solar charger with the panels.
With my four 12 volt 105 AH Safari lithium batteries and power usage, I'm thinking any where in the range of 900 to 1000 watts for the panels. Same panels without the thought of adding any, using my Honda generators as a backup as needed. Obviously for running the A/C.