RV Solar Part IV – Panel Tilting & Winter Solar Optimization

Paul and Alex go a-panel tilting

It’s been almost a year since we made the leap to solar on “the beast”. For those of you who missed the chair-gripping series I’ve got the whole exciting detail of how we decided what to buy and install in Part I (discovery), Part II (equipment) and Part III (installation). Since that time we’ve been geeking out and enjoying our panels through extensive dry-camping travels from FL to CA. I’m happy to say our panels have served us perfectly. On good sunny days we’re usually fully recharged on the batteries by noon plus the panels easily keep-up with our daytime power usage even if we’re on the internet all day. There’s honestly not much we’d change.

But there’s always an opportunity to geek out a little more. As days grow long and the sun sits lower in the sky we’ve started to think about winter solar optimization. Now solar panels actually like cooler temps (their output increases at lower temps), but they have a problem with angle which opens up all kinds of fun thoughts and experiments on tilting. And opportunities to blog, of course. So, here we go:

1/ Why Tilt Your Panels?

In winter the sun stays closer to the horizon

If you remember my lessons from last year, getting the best out of your solar system is all about minimizing loss. The same lesson applies to tilting too. The power density of a solar panel is always at its’ maximum when the solar panel is exactly perpendicular (at 90-degrees) to the sun. The further you get away from perpendicular the more power you lose and so the less power output you get. Since sun angle varies by both latitude and time of day that means your power output is varying all the time. So, how do you know what to do?

Well, in summer the sun will get pretty high in the sky and stays there for quite a few hours (as an example, here in Palm Springs it gets to ~70-degrees elevation) so your panel output will be pretty darn good even if they’re flat. However in winter everything changes -> the sun stays closer to the horizon (here it only rises to ~30-degrees) and your power output plummets. Sunearthtools.com has a really geeky cool page that’ll give you the exact angle of the sun any time of year for any direction and spot (just plug in your location):

Solar Diagram for Palm Springs, CA from Sunearthtools.com. The top line shows the sun angle in mid-summer, the bottom line for mid-winter.

How much of a deal is this, power-wise? In Palm Springs in summer you really don’t lose anything by keeping the panels flat whereas in winter you’ll lose more than 50% of your power output if you keep them flat. It’s HUGE!! To demonstrate this here’s another cool tool that’ll calculate daily flux (= an approximation of the total amount of energy hitting your panels) based on location, time of year and tilt.

2/ How Do You Tilt?

Our home-made tilt bars

The fanciest type of tilting systems are “sun trackers” that exactly track the sun all day long, but these are not exactly practical on a free-wheelin’ RV roof. Some RVers keep their panels mobile and just bring ‘em out to tilt/track the sun manually whenever they need them. With 6 heavy panels to lug around that wasn’t an option we wanted on our “beast” so it made a lot more sense for us to permanently attach the panels and look for other tilting options.

Our solution was to get the AM Solar mounts (highly recommend them, even if you aren’t going w/ AM Solar for the rest of their gear), and then add-on home-made tilting bars. Some basic 1/4″ aluminum stock from Home Depot cut to whatever length you want with holes drilled in (you can even drill multiple holes to have multiple tilt options). Combine with screw/nuts and you’re good to go!

3/ What’s The Best Tilting Angle?

If you’ve made it this far and manage to remember what we talked about in #1, then you know that what we’re looking for is to get your panels as close as possible to 90-degrees to the sun. The cool sunearthtools.com link will tell you what angle the sun gets to in your area, and some simple geometry will give you the optimal tilt angle:

At our current latitude and time of year we’re talking around 60 degrees tilt at noontime for best results. Now, obviously the sun moves diagonally across the sky during the day and rises/sets somewhat southerly in winter so that number doesn’t stay constant and the real (max. total energy) formula is a rather more complicated (the cool tool shows that). But if you face your RV East-West and tilt panels facing due south more or less at the 90-degree noon-spot you’ll get pretty darn close to getting the best out of the sun.

4/ Beware the Shadow Monster

See ma...NO panel shadows!

Tilting is just like everything in solar. You’ve got to make sure you avoid ALL shadows. Together with Marvin we were very particular when we installed our panels last year to make sure they had NO shadows from anything on the roof whether tilted or not, even with long winter shadows. I’ve seen shading models that show just 3% shading of a solar array can lead to a 25% decline in efficiency, with 10% shade producing up to 50% decline! The losses are dramatic and could mean the difference between a system that works and one that doesn’t. Even panels that have special “bypass diodes” (meant to help the shade problem) will suffer voltage loss for each cell shaded. Don’t be caught by the shadow monster!

5/ And Our Results Were….?

We conducted our little tilting experiment out in Owl Canyon BLM. Our tilt-bars only go to ~45-degrees so we knew we wouldn’t get optimal output, but we expected a pretty significant boost. Mid-morning with panels flat our 600W system was putting out ~20Amps. With the tilt we hit ~30 Amps, a 40% improvement. As the day wore on our boost got even better with the MPPT charger kicking up output to a stunning peak of~45 Amps at around noon (MPPT really shines with higher-voltage panels in colder temps). Coooool!

We plan to do even more detailed tracking experiments later this the winter and will undoubtedly share these exciting results with our readers, but for now this is a good start. There is also much more geekiness that can be done with solar so don’t expect to see the last of this sunny series.

NF Campground Review – Mesa, Lake Roberts, Gila National Forest NM

Gorgeous Lake Roberts

A very relaxing and pretty National Forest campground next to Lake Roberts in the Gila Wilderness in SW New Mexico.

Link to campground here: Mesa Campground, Gila Forest
Link to map location here: Mesa Campground, Gila Forest

1. Site Quality = 5/5
   Really lovely sites here with easy access even for “beast size” RVs. All are very flat, large paved sites with lovely and large ”sitting areas”, picnic table, fire-pit, grill and personal trash cans. Selection of back-in, pull-in and pull-throughs as well as ~12 hookup sites (30Amp/water). All sites have excellent separation and lovely views of open hills and trees. Select sites in front of the loop have lake views (#15, 16 and 19/20).
2.  Facilities = 3.5/5
   Very decent facilities for a Forest campground. Flush toilets, kept nicely clean (no showers). Also, on-site dump station (not mentioned on the NFS website, but it’s there!). Boat ramp and fishing piers by the lake as well as picnic areas.
3. Location = 5/5
   This is a lovely and remote location. You’re ~21 miles up on Hwy 35 deep within the Gila Wilderness. The campground has pretty views and access to lovely Lake Roberts as well as several cool hiking trails. You’re also only ~40 mins from Gila Cliff Dwellings.
4. Pet Friendliness = 5/5
   Very, very dog friendly park. Lots of space to hang out and relax, plus plenty of hiking both around the lake and near the campground (big bonus is that many trails allow “voice control”). Locals and host are very dog-relaxed. While we were there we even had a daily visitor, Booger a dog that lives ~4 miles away, who made the trek everyday to visit the campers and campground (Polly had alot of play-fun!)

Overall Rating = 4.6
BONUS ALERT = Relax with a view of the lake and hills deep in the Gila Forest!

Summary: If you’re looking for relaxation and forest it really doesn’t get better than this. Lake Roberts is located ~21 miles up Hwy 35 deep in the gorgeous Gila National Forest at ~6,000 feet. It’s a bit of a narrow (and sometimes) bumpy road coming up, but the location is beautiful. There are actually two campgrounds within ~1 mile of each other -> Upper End (which is on-level with the lake, but doesn’t have any views of it) and Mesa (which is above the lake and some sites have views). Both campgrounds are big-rig friendly, but we thought Mesa the prettiest. Sites are wonderful paved, flat with picnic table, fire-pit, grill, great separation and even a selection of electric/water hookups. Several sites near the front (#15,16,19, 20) have lake views. We chose #16 which was non-hookup, but enormous (huge) and our choice for the nicest in the loop. There’s lots of activity to keep both you and doggie happy including hiking, fishing and sight-seeing (Gila Cliff Dwellings). During the week this place is completely empty, but it does fill up with locals (and kids and dogs!) in the week-end. A simply lovely campground and we’d definitely come back.

 Extra Info:  NO Verizon coverage (zip, nada, zilch)…need to drive ~15 miles back towards Mimbres before you get a signal. Sites cost $10/night for non-hook-up, $15/night for water/30Amp electric (~12 sites). First-come-first-serve only. On-site dump station in Mesa campground.

Extra, Extra Info (BOONDOCKING): For those looking for a cheaper alternative Gila Forest allows camping anywhere you can legally drive. We saw an easy, flat forest service road between mile-markers 18 & 19 on left-hand-side  leading to an open field with several big-rigs. Also, there is a free campground (Forks Campground) a few miles south of Gila Cliff Dwellings for those brave enough to make the drive (Hwy 15 can be somewhat hairy). Forks is mostly for tenters or small rigs, but we saw at least one site at the very top (near the road) which would certainly fit a big rig.

Our gorgeous, enormous site (#16). No hook-ups, but oceans of space & views of the lake from the side.

Typical back-in site view (#22 shown)

View of back-in electric/water site (#18 shown)

Typical pull-in site (#9 shown)

View down campground loop (site #8 shown on left)

Another view down campground loop

Picnic table, fire-pit and grill at each site (this is site #19 which has a lake view)

One of the many gorgeous hikes near the campground (this one is Purgatory Chasm)

Boondocking Site Review – Calaveras Lake, San Antonio, TX

View from the banks of Calaveras Lake

This is an inexpensive dry-camping location just next to San Antonio. It’s not exactly a boondocking location, but doesn’t really qualify as a campground either, so I’ll rate it as a boondocking spot. Unfortunately it doesn’t make our favorites list.

Location: Calaveras Lake, San Antonio, TX
Coordinates: 29.305861,-98.298798. Link to map location HERE. 
Cost: $4/person/night
How We Found It: Using Don Wright’s “Free Camprounds” book.
Nearest Dump/Water: ?? Not sure.

1. Access – 4/5
   Very decent access here, but sites are mixed. The road into Calaveras Lake is paved and access inside the campground is decent. You can set-up anywhere around the lake once inside the facility. Most of the banks are very uneven/sloping, but there are a select number of flat areas and a few nicer spots right on the water.
2. Nature – 2.5/5
   Nature-wise this is a bit of a mix. On the positive side you are right by the Lake with access to fishing and water activities, but your view is marred by a large power plant on the right-hand side and the area around the lake has limited space/activity. A small nature trail on-site, but no real hiking.
3. Isolation – 1/5
   The Lake is outside of town and so does get bonus points for being “away from the city”, but its location makes it extremely popular with the locals. The park doesn’t seem to limit how many people access/camp here so don’t expect to be alone.
4. Pet Friendliness – 3/5 
   The park is pet-friendly, but there’s very limited area to hike/walk pooch. A strip of green along the back power-lines and a small nature trail pretty much make up the lot. Pooch does have access to the lake.

Overall Rating = 2.6

Summary: So, this was one of those spots that looked great on paper, but didn’t work out for us. Our experience was no doubt marred by the fact that we camped here during Spring Break, but there were also other aspects which made it less than great. Location-wise it’s a good spot -> only 10 miles from San Antonio, right on a lake with access to fishing and green for a mere $4/person/night. Camping is “free access” to wherever you can park on the banks of the lake. There are a select number (8) of designated sites on the North side that you can reserve beforehand. However the overall area is limited in size, there is a large power plant across the lake (mars your view) and the management doesn’t seem to limit how many people can camp there. So in busy times it literally packs in with as many folks as can possibly set-up on the banks.  When we first arrived it was fairly quiet and if we’d come here mid-week during low season we might well have found a nice (and somewhat peaceful) spot to enjoy the water and the area. However our experience that evening with the big build-up of people was, unfortunately, downright uncomfortable and we decided to leave. If we come back we’ll probably try a different location.

Extra Info: On-site flush toilets, but no water or other facilities. Verizon smartphone and aircard worked.

NOTE/ All below pics we taken when we first arrived (before the big build-up of people in the evening):

Front view of our parking site at Calaveras Lake

Side-view of our parking spot and the main campground road (on left)

View out the side-window of our RV.

Walking under the power-lines with Polly. View of the power plant in the background.

Boondocking Made Easy -> LED Lighting

One of our G4 bulbs and the LED we chose to replace it

Since we’ve got a few extra days of hanging out while Polly heals I thought I would add another post to my boondocking series, this time on LED lighting. Now, I consider LEDs a luxury rather than a necessity for dry-camping. You can easily manage without and, given their price, it’ll take a good few years before you make back your investment in pure $$, but the fact that they drop your power draw for lights by a factor of ~10, that their lifetime is almost infinite (up to 50,000 hours) and they run super-cool make them fascinating for a self-confessed geek like me.

A reading spotlight (1383 bulb) and the LED we chose to replace it

Oh, I wanted them…oh, yes I did…and thankfully LEDs have come a long way since the days of the dim red types that were used for calculator displays. Nowadays LEDs are both brighter, more efficient, more reliable and available in a range of colors. Technically LEDs are semiconductors, light emitting diodes, and there are a bunch of different types and an even bigger bunch of companies that manufacture bulbs from them. However they all use a similar rating system and that’s the system you want to understand when you buy a replacement for one of your RV bulbs

1. Lumens - All LED lights will have a lumens rating which tells you how bright you can expect the bulb to be (as perceived by the eye). The higher the lumens, the brighter the bulb.
2. Color Temperature – The color temp is usually listed in K (Kelvin). If you cast your mind back to high-school science you might recall that in a burning fire, the blue part of the flame is hotter than the red part. In very rough terms that pretty much explains how color temps are defined. A higher K rating (~5,000K) is blueish-white in color while a lower K rating (e.g. 2,000K) will be yellow-red. Most incandescent lights that you have in the home run around the 3,000K range.
3. Operating Voltage & Regulation - LEDs are quite sensitive to voltage. Their I-V curve is exponential meaning a small voltage change can produce a very large current change, potentially damaging your expensive LED. In practical terms LED lights really prefer a very constant/steady power source which is exactly what you don’t have in an RV. The batteries in an RV go from anywhere from 11V to 14V, depending on charge. So, for RV LED lights you really want to make sure the bulb you buy either has a built-in regulator or states it’s rated to handle a range of input voltages (e.g. 11-15VDC or 8-30VDC). This is one feature that a “cheap” LED bulb might not give you.

So, your handy-dandy steps to buy an LED replacement are as follows:

1. Identify Your Bulb - There are all kinds of bulbs inside a motorhome with names like G4, 1156, 1383. This site provides a nice, handy reference for some of the more common bulbs to help you figure out what kind you have.
2. Choose Your Brightness - For accent lighting somewhere around 100-140 lumens is fine. For spot and reading lights you want somewhere around 160-300 lumens or more, and for much brighter applications you may want to go above that. For reference a standard 40-watt incandescent bulb produces ~520 lumens (this site provides a nice table of lumens/watt produced by various types of bulbs).
3. Choose Your Color - The blue-white LEDs are often called “white” (~5,000K) and do tend to run brighter than the yellow LEDs called “warm white” (~3,000K). Outside the motorhome (e.g. for the porch light) I have no issue with a bright blueish-white color, but inside the motorhome I personally prefer the warm white color more like a regular incandescent bulb.
4. Make Sure it Has Regulation – For your LED to last the lifetime you expect it to, it needs to have regulation to handle the varying voltages in the RV. So, check that the vendor either mentions a “regulator” circuit of some kind or specs a wider operating voltage range. Most of the good vendors have this, but some cheaper ones might not.
5. Test it Out – No matter what the “spec”says on the website you’ll get variation in color and brightness from different vendors.  Taste is individual so some people may want more brightness or a different color than others. It’s always worth buying 1 or 2 bulbs just to test them out before you spend a bundle and replace a bunch.

Our new LED bulb (on left) as compared with the old 20W halogen (on right)

We replaced our G4 halogens with these bulbs from LED Wholesalers through Amazon. We are very happy with both the color and brightness (they easily matched the 10 & 20 Watt halogens that were in the sockets previously).

We also replaced some reading spotlights in our bedroom (1383 bulbs) with these bulbs from buylighting.com. The beam from these bulbs is much more “narrow” than our old 1383′s, but brightness  and color are good.

Other good vendors that we’ve seen mentioned on the RV forums:

• Super Bright LEDs
• LED Trailer Lights
• Command Electronics

The overall result? We loooove our new LEDs. They run so much cooler than the old bulbs (no more burning of fingers if you accidently touch the light) and our energy usage has dropped by a factor of ~10. When we turned on our living room lights in the old system we would run ~8-10 Amps. Now we run only ~1 Amp with all the lights on.

There’s much, much more to this whole LED business as with all things geekish, but hopefully this little intro can help you burn the night away in the most energy efficient of ways. Your batteries will thank you for it

Boondocking Site Review – Sea Rim State Park, Sabine Pass, TX

Walking the coastline at Sea Rim SP, TX

FEB, 2012 UPDATE -> One of our blog readers is workamping at Sea Rim SP & told us camping is (unfortunately) no longer free. There is now a $10/night camping fee (no hookups)

So, I’ve been trying to come up with a good method for reviewing and sharing our boondocking spots as we travel out West. Clearly things like facilities and amenities don’t apply to this kind of camping. For me, boondocking is all about getting “out there”, so I’m going to focus on it from that point of view and swap out the ratings to items which apply to that. This is a new category for me, so feel free to chime in and let me know if there’s anything you’d like to see which is missing:

Location: Sea Rim State Park, Sabine Pass, TX
Coordinates: 29.674966,-94.044471. Link to map location HERE.
Cost: FREE (no permits required)
How We Found It: By accident. I was looking for camping along the North TX coast using Google Maps. Spotted the green area of McFaddin National Wildlife/Sea Rim and called up the rangers to ask about it.
Nearest Dump/Water: ?? Not sure. Spotted some private RV parks coming down SH 87 at Sabine Pass so that would probably be the place to ask.

1. Access – 5/5
   Very easy access and camping here, even for big-rigs. The road leading down to the coast (SH 87) is excellent and the State Park itself is clearly marked all the way from Port Arthur. The park has concrete roads and 2 large concrete parking areas which are open for boondocking. Camping is also allowed anywhere on the beach. Beach is fairly firm, but tides can be deceiving, so park well back from the water.
2. Nature – 5/5
   Excellent nature here. Fully open beach views from everywhere in the park including both concrete lots. 5 miles of open coastline to hike and play. Small nature trail on East End of park.
3. Isolation – 3/5
   The spot is nicely located at the Southern Tip of Sabine Pass. You’re ~10 miles from Sabine Pass and during the week very few people come out here. On the week-end however, you will get locals coming to walk, fish and hang out on the beach. The State Park Ranger also patrols on a regular basis.
4. Pet Friendliness – 5/5
   Very pet friendly location. The beach and all surrounding areas are open for pooch. Direct access to beach-combing right from your RV.

Overall Rating = 4.5
BONUS ALERT =  Camp with an open view of the ocean!

Summary: This is a great little spot ~10 miles West of Sabine Pass. It’s a super-easy “starter” location for RVers who want to try boondocking for the first time, but it may not be around for long! The State Park was completely destroyed during the last hurricane, so the rangers decided to allow free camping until they’re able to re-build the facilities (the info on the SP website is wrong -> the camping and access is completely free for now). It’s a wonderful spot on the TX coast with fully open beach views and over 5 miles of coastline to play on. You can boondock either on the concrete parking pads in the park or anywhere on the beach. The area doesn’t have shelter so you’ll feel the winds when they whip up (as they do often down here), but the untamed beauty is gorgeous. During the week it’s very quiet and very few RVers come here, but the locals do show up on the week-end. Nearest shopping is ~20 miles away in Port Arthur so come prepared. This was a superb spot and we would definitely come back. Get down here while you can!

Extra Info: Porta-potty on-site, but no water or other facilities. Verizon smartphone worked (only just…1X bar). Verizon aircard worked, but needed external antenna/amplifier.

View of the road and one of the boondocking concrete parking lots

Back view of our RV from our parking location. The ocean view is in front of the RV.

View of 2nd concrete parking area. Porta-potties on left.

RVer boondocking on the beach

View in front of our RV, just across the road.

The fabulous coastline. Wild and deserted!