Going Solar - Have Questions

[GeorgeR]

Originally Posted by jeckel30

I am thinking about getting 2 panels though and would be relying heavily upon solar. I am not sure which way to go.

Use numbers in your decision, opinions are often good but they are just opinions.
George.

[Byron Kinnaman]

Originally Posted by jeckel30

I have been reading every thread on this board regarding solar this past week. I have some questions that I have yet to find some current answers to. I see a lot of threads from 2-3 years ago but I know the technology and prices have changed a lot.

I see in most threads from earlier this year and last that it is popular to buy the 60w panels. As I look around Ebay I see that 75w ones are only about $25 more. I am looking in the 60-80w range and wondering what currently is the best panel to buy? Are there brands to look for and ones to avoid?

Also when it comes to a solar controller it seems like Morningstar and Sunsei are the brands to go with. My question is which one is a good one to go with? I see they range anywhere from $35 on up to $200+. I am hoping a sub $100 will do the trick but if it is really worth stepping up to the $200+ ones I will do it. Is there a good middle of the road controller?

This is all going on my 13ft Scamp I picked up a few months ago and now am getting ready for fulltiming next year with my wife.

You don't need a large controller. I'm using the $35 dollar variety. It's a 6 amp controller and I have 65 Watt Panel with a maximum output of 4 amps. Don't bother to connect the "load" connection of the controller. Since all I'm doing is charging the battery I all I need is the solar panel connection and battery connection. I used this for about 3 years now. Last winter out of 3 months+ I was only connected to power about 1 week.
Good luck.

[Stoney]

Check out Handy Bob's blog you can google it , the rv battery charging puzzle was an interesting read , cheers mike

[kevin61]

YouTube - ‪Solar panel mounting system on top of a 1976 Boler trailer.‬‏

I have several videos showing the solar install on my 13 ft. Boler. Should be able to find them all on my YouTube channel. I have 160 watts and find this more than adequate for my needs

[jeckel30]

Originally Posted by kevin61

I have several videos showing the solar install on my 13 ft. Boler. Should be able to find them all on my YouTube channel. I have 160 watts and find this more than adequate for my needs

Which controller are you using?

[Andy B]

Originally Posted by Ron F

I won't always be parked in complete sunlight and the fixed install doesn't allow me to aim the panels for the best power generation.

The panels are multi-crystal, which is middle of the road in terms of efficiency. Mono-crystal panels are more efficient, but cost more. Amorphous panels are the least efficient and cost less. The higher efficiency lets you put more wattage per square foot. It' really a trade off in my mind.
Ron

One thing to keep in mind when discussing solar panel efficiency is that the rated output is under optimum conditions and those optimum conditions do not exist very often in the real world. By optimum conditions I mean there is full midday sun, no clouds or fog, the panel is kept cool, there are no shadows from tree branches or light poles and the panel is aimed perfectly at the sun.

Under those conditions the multi and mono panels will produce more power per square foot than the amorphous panels. The peak power produced is a misleading specification to use when making a decision on what type of panel to buy. What really matters is the total amount of power that the panel puts into the battery each day. High power output for a short time may not charge the battery as much as lower power output for a longer time.

Under many less than optimum conditions the amorphous type has an advantage over the other types. They will produce power earlier and later in the day. They will produce power in shade or part shade when the other types will not. They are better at producing power when it is cloudy or overcast. They work better at less than optimum angles like they would be if mounted fixed on the roof. The power does not drop significantly in high temperatures like the other types do. They also cost less. Depending on the real world conditions they may not even need to be larger if comparing total power in a day and not just peak output.

The poly and mono panel output can drop low enough to not provide any charge to the battery if there is something as small as a tree branch shadow across just a portion of the panel.

I would love to see a comparison of the total power produced in a day from all 3 types of panels under real world conditions but all I ever seem to find is peak power output.

[kevin61]

Originally Posted by jeckel30

Which controller are you using?

It should be in one of the videos. You will have to look around.Morningstar Sunsaver MPPT I think
Should be videos in there to answer most of your questions

[Raz]

We have about as simple a system as you can have. A 42 watt amorphous panel that produces 2 - 2 1/2 amps tops with a home brew controller. With such a low current, a controller really is optional as long as I keep an eye on things. The battery is a Lifeline group 24 Agm. In the trailer we have LED lights, the occasional water pump use and a modified O2COOL fan. There is also the occasional camera or ipad charging. The goal was to use less that 5 AH per day which the panel can easily handle. We have camped for weeks, no problems so far. Raz

[Francesca Knowles]

Originally Posted by P. Raz

. The goal was to use less that 5 AH per day which the panel can easily handle. Raz

For planning purposes, this approach makes a lot of sense to me!

Francesca

[peterh]

A few thoughts to add to the discussion so far:

First, unless you're installing hundreds of watts of solar panels, you don't need a super-fancy controller. One of the basic Morningstar SunSavers will do just fine, and you can use the money you save on the controller to buy a nicer battery or larger solar panel setup that will deliver more bang-for-the-buck.

Roof-mount vs movable: It's not so much a question of which is better, but which is better for you. A roof-mount system, like ours, is difficult to steal and requires no set-up time; you just park and enjoy. Its downside is you sometimes wind up parking in a sub-optimal space that has less sun, which is why transportable systems are popular. Pick the system that matches your wants and needs.

Which brings me to solar panel size and where to buy. Big solar panel arrays look sexy, but, unless they are attached to batteries that are capable of storing their output and RVs that are likely to use that output, they're more flash than function. If you convert your trailer to LED lighting and don't use a lot of power-hungry appliances, a roof-mount system of 80-100w or portable system of 60w should more than meet your needs.

I buy my panels on eBay, looking for the best price I can get from a vendor with high sales figures and an excellent rating. High sales figures mean they make a lot of panels, so they have a lot of practice at getting all the solder connections and mounting done right.

Last thought: A system is only as good as its weakest link, so don't over-engineer one part of your system -- buying more solar panels or a super-wonderful charge controller -- then skimp on your battery, wire, and connectors. An 80-amp AGM deep-cycle battery, 12g or 14g stranded wire (marine grade wire on the outside, standard inside) with as few connections as possible, and marine-grade wire connectors are all wise investments.

[jeckel30]

Originally Posted by peterh

A few thoughts to add to the discussion so far:

First, unless you're installing hundreds of watts of solar panels, you don't need a super-fancy controller. One of the basic Morningstar SunSavers will do just fine, and you can use the money you save on the controller to buy a nicer battery or larger solar panel setup that will deliver more bang-for-the-buck.

Roof-mount vs movable: It's not so much a question of which is better, but which is better for you. A roof-mount system, like ours, is difficult to steal and requires no set-up time; you just park and enjoy. Its downside is you sometimes wind up parking in a sub-optimal space that has less sun, which is why transportable systems are popular. Pick the system that matches your wants and needs.

Which brings me to solar panel size and where to buy. Big solar panel arrays look sexy, but, unless they are attached to batteries that are capable of storing their output and RVs that are likely to use that output, they're more flash than function. If you convert your trailer to LED lighting and don't use a lot of power-hungry appliances, a roof-mount system of 80-100w or portable system of 60w should more than meet your needs.

I buy my panels on eBay, looking for the best price I can get from a vendor with high sales figures and an excellent rating. High sales figures mean they make a lot of panels, so they have a lot of practice at getting all the solder connections and mounting done right.

Last thought: A system is only as good as its weakest link, so don't over-engineer one part of your system -- buying more solar panels or a super-wonderful charge controller -- then skimp on your battery, wire, and connectors. An 80-amp AGM deep-cycle battery, 12g or 14g stranded wire (marine grade wire on the outside, standard inside) with as few connections as possible, and marine-grade wire connectors are all wise investments.

We will be converting our lights to LED and won't have very many appliances at all. Mainly we will be charging a computer a few times a week(when we can't make it to a coffee shop or elsewhere).

The panel is for sure going to be mounted on the roof. I am thinking 100 watts should be sufficient.

So you think an AGM deep cycle battery and a cheaper Sunsaver is the way to go? I read through Bobs Solar guide and it seemed he leaned towards a normal flooded deep cell and a bit better of a charger(at least 3 stage or 4 stage). I am probably over thinking all of this.

[Francesca Knowles]

Originally Posted by jeckel30

I am probably over thinking all of this.

Josh,

Please don't stop-that's one of the best things about these forums!
The sum of everybody's "overthinking" often adds up to big pools of useful info

Francesca

[peterh]

There's a lot of over-thinking solar install.You're not the first, nor the last.

Flooded cells have a few disadvantages that AGM batteries don't suffer from. The most obvious is AGM batteries are zero-maintainance, meaning you don't have to check and re-check the battery water levels to prevent them from damage and both permanently and temporarily loosing their ability to hold a charge, but there are other reasons, too.

For one, AGM batteries are less prone to sulfation, the formation of battery-killing lead sulphate crystals, at all points throughout their life cycle. Discharge a flooded battery below 75% and it starts to sulphate, put a flooded battery out on a hot day, and it starts to sulphate, let it sit on a shelf and it will sulphate. AGM batteries resist sulphation to 50-60% and are more tolerant of hot days and siting unused on a shelf.

AGM batteries are also more efficient, that is their design inherently allows them to accept and release their charge more efficiently than flooded cells do.

Lastly, a well-cared for AGM battery will survive mis-treatment and last longer. My Scamp's battery is an AGM, and I have abused it mightily, yet it has lasted 5 years and only now needs replacing, where few flooded cells make it to their third year, and if I hadn't had those problems in Yellowstone or had used a Morningstar controller with a battery cut-off for when the charge drops too low it'd probably still be in great working condition.

You might want read this web page about batteries to learn more about battery types.

[Byron Kinnaman]

I'm going to add to the discussion about mounting solar panel(s) on the trailer or not. From observations and reading. the optimum mounted orientation is pointed south and at a 60° angle. Flat mounted on the top of a trailer it's pretty far off from the 60° angle.
You need a lot more panel for roof mount to compensate for the short comings of mounting angle.
My panel is almost square and a frame to stand at close to the 60° angle was easy to make with aluminum angle and pop rivets. I can move it around to get the best angle at the sun.
I also have another reason for the moveable stand arrangement, I carry a second battery in the truck to use with my ham radio. My arrangement has kept both batteries charged when stopped for more than 4 or 5 days. I don't need to charge the house battery when stopped for less than 4 days.

[Rick G]

Originally Posted by Byron Kinnaman

I'm going to add to the discussion about mounting solar panel(s) on the trailer or not. From observations and reading. the optimum mounted orientation is pointed south and at a 60° angle. Flat mounted on the top of a trailer it's pretty far off from the 60° angle.
You need a lot more panel for roof mount to compensate for the short comings of mounting angle.
My panel is almost square and a frame to stand at close to the 60° angle was easy to make with aluminum angle and pop rivets. I can move it around to get the best angle at the sun.
I also have another reason for the moveable stand arrangement, I carry a second battery in the truck to use with my ham radio. My arrangement has kept both batteries charged when stopped for more than 4 or 5 days. I don't need to charge the house battery when stopped for less than 4 days.

You bet, all of those are very good points. I thought about it for the past few months, then last weekend installed our solar system on the trailer roof. The biggest reason is convenience.

On my previous Boler, I installed the solar panel (I have two 40 watt panels but have only ever needed one) on the roof of the tow vehicle, a minivan, with the wires running through the 7 pin connector, and the charge controller installed in the battery box with the battery. This worked great, no wiring inside the trailer at all, and I could move the van around when camped to get sunshine (we had an extension cord with 7 pin connectors on it so I could separate the trailer and tow vehicle. However, even that was too much trouble for us, as we like to have no hassle at all when camping, or at least limit the hassles to food and recreational activities. With LED lights and propane appliances, the setup was more than adequate for extended camping for us.

So, on the new trailer I decided to mount the panel on the roof of the trailer, using 4 L-shaped aluminum brackets (my panel has an aluminum frame). The brackets were attached to the frame using one screw installed fairly loose, then stuck to the roof with 3M VHB tape and then a second screw put into each bracket to conform to the roof angle at that particular place. Each L bracket was about 6 inches long and about 1½ inches wide, so there was plenty of surface area for the VHB tape, and I cleaned the surfaces according to instructions. Having done a VHB tape test a couple of months ago, I am confident that it will be almost impossible to remove unless I am really trying to get it off, and not easy even then.

I agree that the angle is not optimum and we will suffer from light loss at times, however, we are willing to have that in order to get the convenience of not having to do anything at all. The wiring is permanently (I hope) installed with “No More Nails” which is a clear VHB indoor/outdoor tape, and the charge controller is again mounted in the battery box out of sight and out of the weather.

As an aside, I had to buy a large roll of the 3M VHB tape from the distributor, so I am now looking for new ways to use it. It is only rated to be good for two years if kept in relatively warm and humid conditions and in a plastic bag. When I take the tape out of its plastic wrap, I can smell the adhesive, which probably means that it loses its stick when it gets old.

Later,
Rick G

[GeorgeR]

Originally Posted by Rick G

................ The biggest reason is convenience.

...............................
Rick G

Ditto,
George.

[jeckel30]

Originally Posted by GeorgeR

Ditto,
George.

George,

What battery are you using?

[peterh]

Originally Posted by Byron Kinnaman

I'm going to add to the discussion about mounting solar panel(s) on the trailer or not. From observations and reading. the optimum mounted orientation is pointed south and at a 60° angle. Flat mounted on the top of a trailer it's pretty far off from the 60° angle.

You need a lot more panel for roof mount to compensate for the short comings of mounting angle.
. . .

That would be (roughly) correct for fixed installations, but a solar panel's true optimum angle is either perpendicular to the sun or arranged or arranged so it is perpendicular to the sun's path in the sky on one plane and the sun's position in the noon sky on the other. These alignments change with the season, and you canactually find nifty calculatorsto tell you what angle to place your panel at for your lattitude and day of the month.

You're dead on about needing more panel for roof mounts, though. A 555w panel would more than meet our charging needs if we could keep it in the sun; instead I found I needed more capacity and nearly doubled to our roof-mount panels to 105w. Now we're cool. ;-)

[GeorgeR]

Originally Posted by jeckel30

George,

What battery are you using?

My trailer came with two 27 series batteries and I added a third 27 one. I was considering 2 Trojan true deep cycle 6V batteries but without major modification (height) they would not fit in the tongue compartment. I maintain batteries as they should be maintain. My 80A Xantrex 3 stage convertor is keeping my batteries healthy for the last 3 years. New addition of solar cells will keep batteries even healthier. I installed semi-automatic water refill; it takes about 3 min. to refill 3 batteries to level.

My personal preference for RV battery is to maintain them well, use 3 or 4 stage convertor/charger, if you have room use 2 6V true deep cycle batteries. 24 or 27 series batteries are the lowest cost option.

I don’t have RV experience with AGM batteries but from my motorcycle experience I don’t like them, their motorcycle life is at best 2 years. I just replace 10 years old batteries on my Ford pickup which is rather good for ordinary lead acid batteries.
George.

[Tim D.]

My SO and I are fulltiming in a Bigfoot 17. The roof has 4 80w tiltable panels. We have never regretted spending the money for the freedom 320 watts gives us. Fulltiming would get old fast were we forced to minimize electricity use much of the time. At the moment we are in the Portland OR area. Skies were cloudy/rainy yesterday and may be so for another couple of days. Two Trojan T145s were at full charge entering the cloudy period and will recover quickly when the sun shines once more. For fulltiming without minimizing I recommend as many watts as our tiny roofs and budgets will allow.