Recommendation for solar panels

[jc_39]

I have a Class A 2019 Sightseer 33C. I don't have any solar panels.
Does anyone have a recommendation for manufacture, size, etc?
I see ads for 12v and 24v solar panels. Which would I need?
Would I need to get an LI battery?
Would I need anything other than the panels to tie into the existing system, and where would it tie in?

[BarryLS]

What is your goal for a solar system?
That is the first step in determining what you need, both in size and other hardware. Typically, you need solar cells and a charge controller. They can be used with your current battery system or you can go for better battery's to get higher energy density and use. You might want an inverter to convert DC to 110ac.

As far as solar panels go, there is an abundance of manufacturers, and you'll typically see around a dollar a watt in the smaller sizes (100w) and that comes down a bit when you get bigger. I'm planning to purchase used solar cells in the 250 watt range because they are still very good and can be as low as $0.25 a watt.

Tell us what you want to accomplish and then someone can help.

[creativepart]

About voltage. A "12v nominal" solar panel will put out about 17v to 21v on a sunny day. That's generally what you want to get.

The higher voltage panels are for higher voltage systems - many times used on a home.

Depending on how you wire solar panels you can make "12v" panels put out much more voltage.

Before moving too far forward on this purchase I'd recommend doing a lot of research about the entire SYSTEM. It's not just panels. It's panels, mounting methods, wiring schemes, wiring routing, solar charge controllers and wiring to your battery bank. Throw in a bunch of fuses, combiner boxes, cutoff switches and perhaps a Buss Bar or two.

Once you get into this it's very simple but you must understand how everything fits together into a complete charging system.

PS. Batteries and LiFePO4 batteries is a whole 'nother story and will require a bunch more research.

[Marine359]

You don’t have to switch battery type.
The solar charge controller(s) you choose are the key components of the system. Many are programmable for battery type. The amperage of the charge controller should be matched to your pv array. I recommend Victron because of their programmability, and Bluetooth compatibility with all other Victron components.

As Creativepart posted, you must plan this out before buying anything. It’s not just a matter of the watts produced by the pv panels. Your installation could be simple or complex, as far as wire routing. Fortunately, since you have a fiberglass roof, mounting should be fairly simple just using vhb tape.

You may want to consider first experimenting with a portable panel. Installation is a snap, in less than an hour, and you don’t have to go up on the roof. There are several brands of portables that use the newer EFTE/PERC technology. These panels are usually soft-folding, very lightweight (7 lbs) and nearly as efficient as hard glass panels. But they are a bit more expensive than other folding “suitcase” panels. If you buy one of these, and put an mppt controller near your battery, it’s easy enough to connect to the panel through a SAE sidewall port. I always advise against portables with built-in pwm controllers. With mppt, you can farm far more charge current in a single day because they are far more efficient at producing charge current in lower light conditions, such as mornings and evenings, times when a pwm might not even switch itself on. In a nutshell, a portable will give you some experience with solar, and reveal to you how much solar you really need. For some folks, one or two portable panels is all they need.

[Marine359]

One other thing JC.
You need to know how much power, expressed as amp hours you consume in a normal day of camping with no hookups. Measuring battery voltage is not an accurate method of calculating consumption. The first thing you should buy, if you don’t have one is a Bluetooth enabled negative shunt battery monitor. For $125, and 1/2 hour of DIY install time, you’ll learn exactly what’s going on with your battery; how much amperage is coming in, going out, and State of Charge. Since the purpose most people buy solar is to replace amp hours consumed in a day, you can’t intelligently size your solar system without this information.
Good luck on your solar adventure.

[Fanrgs]

Since you asked about 12v or 24v., look for articles and videos comparing 12v and 24v PV panels. As mentioned by others, 24v panels can be much cheaper per watt. Coupled with an MPPT controller, 24v panels are often more efficient; will start charging 12v batteries earlier in the day; and can use cheaper, more flexible, smaller AWG wire, so can be run for longer distances with minimal voltage loss. All of this info can be found in solar systems spread sheets online.

But before beginning your design, you need to add up the 12v battery amp-hours that you use in a day for lights, water pump, furnace fan, vent fans, 12v fridge if you have one, TV, sound system, personal device charging, etc., etc., including parasitic draws like the propane detector. The draw of all these various 12v RV appliances can also be found online. When you have estimated the total amp-hours that you use in a day, you will know how many amp-hours that your solar system must produce. This then determines the size PV array you need and the size of the MPPT controller to provide those amps to the batteries. And keep in mind that if you have 12v deep-cycle, Gel, or AGM or 6v golf cart batteries you can only use 50% of the stored amps without possibly damaging the batteries. Lithium batteries may be twice as expensive as good-quailty AGM batteries, but they weigh half as much and can be drawn down nearly twice as far.

The only potential drawback to lithium is that they can be discharged below 32 degrees, but not recharged. So, if you are going to camp or even just drive/tow the RV in northern or mountain climates, you will need to keep the batteries in a heated compartment or use heating pads like those on holding tanks to maintain 33+ temps 24/7.

[BobC]

As to manufacturers, I've stuck with middle-of-the-road brands like Renogy and Grape Solar. I don't see any need to go to premium brands like Zamp.

In terms of type, you want to make sure you get monocrystalline panels instead of polycrystalline panels:

https://www.rvtiresafety.net/search/...ion%20Pressure

Similarly, it's generally recommended that you get an MPPT controller vs. a PWM controller:

https://www.solarcraft.net/resources...ge-controllers

Victron, GoPower and Renogy are popular controller manufacturers. Beware of shopping for the lowest cost controllers you can find.

Although they've improved, flat, flexible panels tend to be less efficient and not as durable as traditional, rigid framed panels. They're also more expensive.

As mentioned by others, your panel wattage and battery capacity need to be consistent with your needs. The choice of LiFePO4 (Lithium Iron Phosphate) batteries vs. traditional lead acid or AGM batteries is a secondary choice and not tied to the solar decision. LiFePO4 batteries aren't necessarily for everyone despite their many advantages. For me, personally, I'm not using my MH enough to justify the expense of LiFePO4 batteries and, at least for now, I'm sticking with my 6V golf cart batteries in series. Keep in mind that the commonly stated payback period necessary to offset the additional cost of LiFePO4 batteries is about ten years. I'd recommend educating yourself as much as possible on this topic before making a decision. It's certainly a decision you can delay until after your solar install.

[moabdds]

I bought used 250w solar panels from SanTan Solar in Gilbert, AZ. They were tested and certified. They have 250 watt ones for as little as $50 each for the most common size, but since I needed a longer, skinnier shape to fit my layout, I paid about $100 each for a less common type. I got 4 x 250w panels for $400. At that time, one new 250w panel cost $400. They had been manufactured 4 or 5 years before, so they probably only have another 20 years on them, which is longer than either I or my motorhome will last. Mine have been on for about 2 1/2 years now and work like a charm. They can also do up all the wiring you need if you give them the measurements. I installed a 3000w Victron inverter and 3x100ah Battleborn lithiums at the same time. I did almost all the work myself, other than wiring the inverter into the breaker panel. (I had an RV shop install a second panel so I could split up which things can and cannot run off the inverter, like the AC.) My wife can run her hair dryer or curling iron (not at the same time) and we use the microwave off it all the time. If you'd like more info on how I did it all, contact me. By the way, don't have them ship them to you. Shipping costs more than the panels! I live in Utah, but bought them on my way home from Quartzsite, so I picked them up at their facility in Gilbert.

[Fanrgs]

I agree that used 24v panels are a great way to get started at a lower initial cost. And, although not specifically RV-oriented, check out Backwoods Solar in Sand Point, ID, for used panels and other sale items. They are willing to discuss your needs for any size system, plus their website has many examples of DIY solar installations.

As for lead-acid vs lithium batteries, we have lithium because our RV has a convection-microwave and no gas oven; one induction and one gas burner; a 12v fridge (that we love!); a 12v antifreeze kit for the Truma water heater; 12v tank heaters; and a 2KW inverter. So we need a lot of battery power to cook meals and keep everything from freezing during Colorado fall, winter, and spring RV use.

Therefore, the type of battery you select needs to fit not only the way you use your RV, but also its appliances and the region and time of year you use it.

PS: if I lived in Yuma year-round, I would sell my rooftop AC unit and install a TurboKool 12v evaporative cooler. Then, with enough solar and battery, you could cool off the RV even on very hot summer days just using the battery, with no inverter or 120v power needed. Our house has been cooled by an evaporative cooler for 45 years and our summer electric bills are 1/3 that of a neighbor with refrigerated AC.

[BarryLS]

Since shipping used panels is expensive unless you are buying a lot of them, check locally on craigslist. I did and found a supplier of used cells 10 miles from me with reasonable prices.

[cruizerEd]

I can recommend you stay away from Grape Solar that I bought from AM solar.

You should only get solar if you need it.

You only need solar if you want to maintain power to systems when there is no grid connection and you cannot or do not wish to run a generator. Typically a generator is much more economical that solar but running one has it's issues and many CG restrict generator use.

Solar is reliable, quite, and very enabling if you need it. Solar can range from a simple system to just keep your batteries topped off when the coach is in storage, to a 2KW system that lets you live off grid with lots of power. A big solar system will make a mess out of your roof, add a lot of wiring, components, and cost a good bit of money. I have had one solar charger fail and all of my panels are coming apart so the systems are not maintenance free.

As for batteries lead acid are just fine if they store enough energy and you don't need to optimize the storage of your solar energy. LiFePo4 are great at storing solar power and can get you a lot more energy storage in a smaller space for less weight. I would not recommend replacing perfectly good lead acid batteries with LifePo4 unless you have establish a real need for them. Once your original batteries are failing seriously consider LiFePO4.

We spend up to 6 months a year off grid, hate to run the generator, have a residential fridge, and prefer to use our induction cook top and microwave. Many people only need to be on battery while they are driving and don't need solar or much battery. You'll probably be somewhere in between

If you want to get a good system at a good price that meets your needs you'll need to get more educated about solar and batteries. You'll also have to spend sometime considering what you want to solar to do for you. There are some good blogs and you tubes channels that cover this. DIY solar is one good you tube channel.

If you don't want to spend the time look for a good vendor and let them guide you through the process. Get a referral for a good vendor from people who have owned their systems for several years. I don't have a recommendation for solar but I do like Starlight solar for batteries.

[BobC]

Originally Posted by cruizerEd

I can recommend you stay away from Grape Solar that I bought from AM solar.

For what reason? More information would be helpful. By and large Grape's review scores are right up there with most other mainstream manufacturers on Amazon, Home Depot and other sites. Any manufacturer can ship a bad panel from time to time.

[cruizerEd]

Originally Posted by BobC

For what reason? More information would be helpful. ...

I have 12 grape solar panels. All of them are delaminating to some degree or another. Here is the worst example but they are all getting progressively worse and will eventually be like this. In this picture you can see where the delamination is approaching the connector. Once the delamination progresses enough it will probably allow moister to enter the connector and cause it to fail. The panel will become inoperable.

Grape solar acknowledge this was a serious problem and the panels should be replaced. They said I had violated the warranty by washing them with diluted vinegar. I have a Grape document that states that you can use window cleaner on the panels. Window cleaner can be formulated with vinegar. I felt this was a completely disingenuous objections.

As for the reviews how many are after 5 years? How many people are inspecting under their panels. How many people can or will come back and update a review.

New Rich solar panels would run less than $3000 delivered so suing is going to have a marginal return. Removing, rewiring, and remounting the panels will not be covered and that is a lot of work I'll have to do even if I can collect from Grape. If I win Grape also will probably only have to ship replacement panels as less than a truckload (LTR) and at my expense. I know this because this is what Grape said they would offer if they replaced any of the panels. This means that even if I win and they agree to replace the panels I'll have to spend over $500 in shipping and have to be able to pickup a pallet of panels. That means renting a pickup truck and driving to an LTR site which are few and far between, have limited hours, and expect you go get in and out fast. So I'll have to spend time and money just to get more panels by a manufacture whose panels are failing and has provided very unsatisfactory customer support.

So that is why I don't recommend Grape Solar.

[jc_39]

Thanks for all the replies. I'm giving up on getting any kind of solar. It is not cost effective.

[BarryLS]

"It is not cost effective."

Probably not if you normally only camp in shore power equipped locations.
Since you never told us what your solar goal was there is no way to determine this.

It's very cost effective for me.

[Winterbagoal]

Originally Posted by jc_39

I have a Class A 2019 Sightseer 33C. I don't have any solar panels.
Does anyone have a recommendation for manufacture, size, etc?
I see ads for 12v and 24v solar panels. Which would I need?
Would I need to get an LI battery?
Would I need anything other than the panels to tie into the existing system, and where would it tie in?

Aren't you glad you asked?