Tag Archives: tilting panel

Solar Charging Stuff for RVs We Should Have Known

winter tilt position on our roof

winter tilt position on our roof

You might be interested in buying into the quietest electrical power generator? There is no fuel to keep up with and pour (and spill). Maintenance is very minimal for the panels, just wiping them off, ensuring they are well-attached to the RV, and keeping the wires secure and free of chafing. You should already be tending your batteries to keep them clean, topped off with distilled water (unless yours are “no-maintenance”), and keeping the connections tightened, no matter whether you have solar panels or not.

pair of 125 watt solar panels

pair of 125 watt solar panels

Solar makes sense for more RVers than just full-timers. These roof-top battery chargers allow us to go most of the year without ever needing to use the trailer’s electrically-powered battery charger. A small solar charging system can tend your batteries for your RV without any shore power connections. A larger system can keep up with all your daily uses for your RV’s batteries including fans, lights, water pump, and even ham radio operations.

from http://www.solarchoice.net.au/blog/wp-content/uploads/Module-cost-vs-BoS-costs-on-average.jpgStill higher end systems can also provide all the DC, or 12 volt power, as well as your 110 volt power for your RV. You could run your microwave, hair dryer, coffee pot and more from your batteries, all recharged with solar panels. Beware though, there are costs to all this. The trick, as with so many things, is to strike your optimal balance between cost and benefit.

Before you consider buying anything, study up a bit.  Don’t buy anything yet!  The two links that follow this paragraph provide helpful information about solar panels, controllers, what sizes are useful.  

Look at http://www.windsun.com, halfway down the page. They have “Solar Information Pages” with good learning info about solar.

Look at amsolar’s rv_solar_education pages. They provide good learning info.

Before you buy anything, read this short post we wrote about installing a meter to measure and record battery usage and capacity.  We highly recommend anyone consider carefully this tool before spending a dime on changing the size of their battery bank or adding more solar panels.  If you don’t know what size shoe you wear, why would you order a pair of shoes without being fitted first?<

Trimetric Meter by our fridge

Trimetric Meter by our fridge

The meter we installed in October 2013, in case you did NOT read the article I just told you to, is a Trimetric 2025RV.  It costs $180 from BestConverter, including the required shunt. You can see it through this link. We bought the approx 25′ of control wire from a really neat store in Boise Idaho, they spooled off 25′ of Cat5 for about $5.  We had the battery cables we needed to connect the meter in-line with our batteries and the house.

No one told us to have a cooling off period or to learn more.  Well, we learned more anyhow — we studied our fannies off learning about so many sizes and brands of solar.  Solar was smoking hot in 2007, the dealers could not keep good panels on the shelves.  Same with charge controllers (you already learned in the first two links way above, these are very important), they were often unavailable.

We somehow stumbled upon a very nicely documented description of installing solar panels ON OUR VERY RV — Yep, Don had installed a pair of solar panels atop a 2005 Airstream CCD 25 trailer.  Wow, we’re supposed to do this.  We tried to be just like Don.  We ordered the same kit from the same place, put our panels in the same spot, installed our charge controller in the same blank panel.  This is too easy!

Well, it wasn’t quite so simple.  You see, you have some days luckier than others.  The day we installed our solar panels was a less lucky day.  Jim drilled holes in our trailer’s roof. Eight 5/16″ holes, four feet for each panel, didn’t take very long to make.  The panels attached easily to the roof with the supplied mounting hardware and . . .

Inside the trailer the 12 volt lights didn’t work anymore.  Oh, it’s probably something really simple.  No. A wire must be cut somewhere from all that drilling.

see the patched hand-hole from patching wires?

see the patched hand-hole from patching wires?

After much snarling and searching and spending sleepless nights, Jim found the one hole in which the drill bit had touched two wires.  The insulation stripped off, the two wires were crossed and shorting out.  Finding the problem was the hard part.  Jim spent only an hour or two fixing these two wires and our solar charging system has worked fantastically since.

Here is one more link, to a seller with very nearly the same system we bought over five years ago. This is our favorite system, the 270 watt one, close to what we have but seems a bit sharper and is certainly much less expensive than what we paid then. The technology has improved in five years, although we’ve read the manufacturing may be lower quality. The article we read from NY Times reported a case where the failure rate for newly manufactured panels has risen from below 5% to between 13 and 22%.

P1120863We are now more advanced users due to lots of practice — full-time with the solar charging system for over five years.  All the components are original, but we’ve enlarged the battery storage to four 6v golf cart batteries.  Jim can now rest assured of having full power for his ham radios before sun-up tomorrow, every day. Debbie rests confident Jim will not once ask her, “are you still using that light or may I turn it off for you?”  We have lots of battery capacity.

arm uni go powerJim installed a neat tilting system for our solar panels. Our panels can be up to 30% more effective by tilting than if lying flat on our roof.  This is especially useful in winter months, when the sun is much lower angle in the sky and solar gain is much harder to obtain.  

both panels now tilt at once

both panels now tilt at once

Our panels, tilted up, are ready to get all the solar they can in winter.  At least each quarter-year, Jim changes the amount of tilt to correspond with the sun’s higher, or lower, path across the sky.  And no, we do not travel down the road with the solar panels tilted up. The panels lie flat on the roof for travel.  Jim can easily and quickly tilt the panels, standing on a ladder leaned against the trailer’s side.

See you down the road!

Jim and Debbie

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©2007-2013 Dreamstreamr

Increase solar panel gain by XX%

panels are mounted on z-brackets 2" above roof

We want to chase 75 degrees all over North America in and, sometimes, out of campgrounds. It is especially nice to camp without needing utility hookups. Several places (e.g., Kentucky Horse Park, several Ohio state parks) allow discounted parking on grass without hookups. Perfect if you don’t need electricity or water — and solar panels are so much quieter than a generator.

We assumed, with two 125 watt solar panels, we could keep them flat on the RV’s roof and we’d have plenty of solar recharging for the RV’s two batteries. This seemed mostly true throughout the past four years. If the solar panels had clear view of the skies, if the weather was fair with lots of sunshine, the two panels did fine.

There are, however, winter days with limited (and low-angle) sunshine when we capture solar energy for far fewer hours. Too, we have been only recharging a 225 amp hour battery bank, a pair of 6v 225 amp hour batteries wired in series. We want to increase our battery capacity by two-fold and we want to increase our solar panels output to the solar charge controller.

Tilting the solar panels seemed the simple solution. Our criteria were, (1) easy to install; (2) easy to operate from a ladder at the RV’s side. We found very nice ready-made tilting hardware from Go Power! through Amazon. We purchased two sets for our two 125-watt solar panels atop our RV.

These Go Power ARM-UNI Tilt mount kits look fine and meet both criteria perfectly. The aluminum parts are smoothly finished and accurately drilled. All mounting bolts, nuts, washers are stainless steel. We mounted the supplied brackets atop our existing Z-brackets on our roof to provide an additional 1.5 inches clearance above our roof surface. All to gain and no disadvantage for us.

10-32 well-nuts

The kits also include a set of well-nuts for mounting through the roof surface — we neither wanted nor used the well-nuts. Oddly, our solar panel package (purchased and installed 2007) also included well-nuts for installing the panel feet (z-brackets) to the RV roof. These well-nuts might be just the trick for some roofs but we just wouldn’t again use them on an aluminum roof like our Airstream travel trailer. The problem with expanding anchors like the well-nuts in a sheet metal roof: they require a large hole and they just aren’t necessary.

Our solar panel installation was to have been a simple affair in November 2007. Jim briefly chronicled it in our journal (see week of Nov 7) at the time and it looks easy if you read it. We might not have mentioned before, Jim spent less than a day installing the solar panels and charge controller and an entire week tracing the resulting short circuit and repairing the damaged wiring inside the RV’s roof. All is well and we know our RV’s 12vdc wiring better for the trouble. But we recommend following an easier path for self-installing your panels.

The large hole wouldn’t have been the problem had Jim used a stop-collar on the drill bit and therefore avoided drilling over an inch below the outer skin and into a wiring bundle. The real trick though, is to dimple the roof with a sharp 8d common nail or an awl. Then use a #12 or #14 x 3/4″ sheet metal screw to fasten the panel attachments.

indenting would have been far superior

A drill bit removes material from about the hole whereas the awl or nail point pushes down and indents the material.  Indenting the roof surface allows the screw’s threads to engage more material than if drilled away. This can provide a very strong and minimal hole without drilling.

These tilt mount kits are expensive and we could have saved a bunch by fabricating them ourselves. However, the included hardware is first-rate and Carmanah Go Power did the engineering and assembling of the kit so we didn’t have to mess with it. Sometimes it’s nice to take the easy, if a little expensive, way to get a project done right the first time.

The result is we now have both our panels tiltable with nicely made aluminum arms and brackets and securely mounted with all stainless hardware. Looks good, works fine. And we’ve greatly increased our solar panels morning and evening gain by tilting the panels to 38 degrees. Big difference.

Jim found a couple of sites on internet (http://energyworksus.com/solar_installation_position.html; http://www.wholesalesolar.com/Information-SolarFolder/mount-info.html) The latter site provided the simplest guideline for solar panel tilt angle relative to latitude and season:

  • February 5th – Set to same angle as your latitude.
  • May 5th – Set at the same angle as your latitude minus 15 degrees.
  • August 5th – Set at the same angle as your latitude.
  • November 5th – Set at the angle of latitude plus 15 degrees.

With one panel tilted at 38 degrees toward the south we have immediately noticed a couple of benefits. We are, by 07:30 a.m. gaining battery charging through our panels to the battery charge controller. We are getting higher amps charging throughout the day resulting in topping off the batteries charging for more than four hours. And we are gaining battery charging later each day due to the panel tilted toward the southern sky.

We can only tilt one panel at a time because they are mounted so close to each other. If we tilt them both then one shades the other, reducing the shaded panel’s output by more than it gained by tilting. With one tilted and the other flat, the flat panel is doing as well as we ever had it and the tilted one is greatly improving its output.

Flat panels were okay when the sun was at its zenith, but the tilted panel arrangement is much more effective. One of our solar panels is aimed nearly squarely at the sun and the other is helping as best it can. As long as we park approximately east-west (or west-east) we can easily tilt one panel or the other from the trailer’s roof edge and boost our solar charging output noticeably.

This has worked out very well. Panel tilting is a cool improvement, and so easy to do.

locate us here
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©2007-2012 Dreamstreamr