I hope you have been following along by reading both Chapters 1 and 2 of this series. Also, my RV Batteries 099 posting from March 8, 2010.
I am trying to keep things simple while at the same time making them clear and understandable so that anyone wishing to explore alternative campsite power will have a good idea about what is needed and even where the bargains are.
.
The two questions that I am frequently asked:
How much wattage will I need?
and……..
How much will it cost?
My usual answer is, “It depends”.
It all depends on how much power you want to use from your battery and how much sunlight you have each day.
OK – I’m going to stick my neck out and suggest a minimum system for anyone wanting to try solar power for their camper.
Batteries – Go for two 6-volt golf cart batteries wired in series to give 12 volts. Purchase the best grade of golf cart batteries you can afford. I strongly suggest Trojan brand batteries. Remember these batteries MUST be installed in a well-ventilated space away from ignition sources.
Solar Panels – 45 watts should keep you up and running if you are a conservative user of power and have at least 8 hours of unobstructed sunlight each day.
Controller – For a 45 watt system you will need at least a 7 amp charge controller.
Page from the HF on-line listing for the 45 Watt Solar Kit
Currently, I see the best buy for the money as a 45 watt solar kit from Harbor Freight Tools. This kit includes three 15 watt panels and a 7 amp controller for under $200. Harbor Freight currently has this item on sale for $149.95 with the super saver coupon. My December/January issue of Field and Stream contained the coupon. Many other popular magazines, including Highways, which is sent to all Good Sam Club members, often have the coupons as well. The super saver coupon is good for both retail stores and on-line orders.
Be advised that this is not the best system out there, but it is one that you can get started with for an affordable price that should work well on your camper.
SAMPLE Super Saver Coupon for 45 Watt Solar Kit. Copies of this coupon are NOT valid.
Keep in mind this system is not adequate for maintaining the current drawn from a battery for a large inverter, which changes the 12-volt battery current to 120 volt household current. Two or more of these kits will come closer to meeting the power demands of an inverter.
Additionally, if you are camping in a cold location where you need to run the camper’s gas furnace, a 45 watt system will not provide enough power to maintain the blower motor. For this situation, I suggest investing in a much larger solar array or purchasing two or more of the Harbor Freight kits and additional storage batteries.
An INDOOR SAFE Infrared Buddy Portable Propane Heater.
To conserve battery power an alternative to using the camper’s gas furnace are propane fueled infrared heaters that are certified for indoor use. We carry two infrared heaters when we camp in the near-by mountains in the early spring or fall. They keep the large fifth wheel camper toasty warm even when nighttime temperatures fall below freezing without draining the storage batteries.
Once you have the solar kit you must decide where and how you are going to mount it.
The best solution is to pack the panels in the camper so that they will travel safely. Placing them on a bed while in route is a popular storage spot. Once at your camping site the panels are placed outside, on the ground, so that they are facing true south or directly toward the sun. As our planet moves, the angle, and direction of the sun will change. Repositioning the panels to follow the sun will provide the greatest amount of power to your storage batteries. Keeping the panels portable will also eliminate the problem of how to run the wire from the panels. The charge controller is mounted in a protected area near the batteries. When you set-up, the wires from the panels are routed through an access door or power cable hatch and plugged into the controller.
3-panel portable solar kit in use by a camper
While I really like a portable system that can be realigned, I elected to mount my panels on the trailer’s roof. This eliminates the need to unpack, set-up and repack the panels. The down side is I am unable to capture as much sunlight due to the angle of the panels and shading from the front air conditioner.
I have six 25-watt panels that can provide up to 150 watts, or 11 amps of charge current. When camped in a sunny spot this set-up will maintain our camper batteries and even allow a couple of hours of power from a 300 watt inverter to operate the LCD television and satellite receiver. The solar panels can easily eliminate or reduce the amount of time we must run a gasoline generator. This is extremely convenient as some camping facilities either have specific generator hours or completely restrict their use.
Author's Permanently installed 150 watt solar array on the top of the fifth wheel camper.
While sunlight is a free and abundant resource for RV power needs, the equipment needed to capture and store that power can easily run into thousands of dollars for a professionally installed system. For some readers, this may be the preferred route. But, if you are handy with tools, enjoy making or adapting accessories for your RV yourself and want to be as green as possible when camping off the grid, an inexpensive starter system like the one from Harbor Freight Tools is hard to pass up.
Next week I will cover the basics of inverters that convert 12-volt battery power to 120-volt household power.
Until then – Happy Camping Trails to everyone!
John Reed
I lived for 3 years off of nothing but one of these Harbor Freight panel sets, 5 truck batteries, a generator and 5 auto battery chargers. Whenever I had to run the gen for power, I charged all 5 truck batteries plus I had 2 – C, AA, AAA – 110 V. battery chargers that charged 4 batteries each running at the same time too. UP in the morning… fire up the gen for microwave coffee (use a french press!) and charge it all for 5 minutes. Got a 12V adapter for my laptop and cell phone… switched to LED lighting. DVD's I watched in the laptop… courtesy of the library… when I needed online.. I bought a cup of coffee in between the rush hour times at Bob Evans and used their WiFi. Had a Nice Park close by so I took 3-5 girl. water bottles there to get my water. Even used the gen to operate a washing machine for my clothes… the solar would never do that! If you're goin solar… learn wattage requirements and use the math and you'll be surprised how well you can do with just a few hundred dollars of equip. Oh yea… I was spending around $7 a week in gas for the gen.
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howe
how would you mount the HFpanels to the roof of an rv? what kind of mounts could you buy and where could you buy them? i would like to permanently mount the panels.
thankx
George
Have you ever looked at these Unisolar flexible solar panels? They are self-adhesive and designed for the channels of metal roofs. I’m not sure what could go wrong, and it might depend on the nature of the RV roof. They are long, so you need to lay them down straight the first time, apparently.
Here’s a link…
http://www.amazon.com/Unisolar-68-Flexible-Solar-Laminate/dp/B002MWDI44
Bernd Deve
Beware a 45watt solar panel power is rated at about 2.5amps at 18v. Once hooked to a depleted battery at say 12.0 volts, the actual power output is actually 12 x 2.5 = 30 watts. Enough to keep batteries charged if using lights sparingly and water pump use. Two standard 12v bulbs consume about 35 watts. Led bulbs consume only 1/6 to 1/10 as much less power, helping keep more battery power. Florescent bulbs are about 1/2 to 1/3 the power of incandescent bulbs. I like the ease of roof mounting, but I like to park under shade of trees – killing roof solar, so I keep mine mobile and place in full sun and rotate them several times during the day for optimal gain. I had the JC Whitney setup , but it couldn’t keep up with my energy needs (I like to watch a movie at nights).
I went with two 90watt panels and a morningstar controller. These panels will put out 5.5amps max each. MPPT controllers are nice, but for the price of a quality unit (the no name ebay units are junk), I’d rather get a standard 3 stage solar controller and spend the saved money for more solar panels. I charge two golf cart batteries, but haven’t had the opportunity to test my new setup yet in the field.
My Sam’s club golf cart batteries only lasted two years. Like the article said, it’s probably worth the extra $ for the top 2 or 3 cart battery manufacturers. I found my two new 90w monocrystaline solar panels on ebay for $360 shipped. Got my morningstar solar controller there also. The more you dive into solar, the more you realize there’s a lot more to learn… Enjoy the experience & I couldn’t do it without Google & internet!
Joseph Mullin
I am in the process of researching solar power and then combining wind power to augment it.
Southwest Windpower has a small unit for RVs and Boats called the Airbreeze. The unit is about 17 lbs but requires an approx. 30 foot tower made of schedule 40 steel pipe. Oh the weight!
I am looking for a hefty solar system so I am currently looking at Krocera solar panels that put out 50 [email protected] AMPS. I figured 3 of these will give me 9 Amps.
Other components
MPPT charge controller from Outback Power
2 Xantrex Prosine 1200 inverters to get 240VAC
2 large AGM batteries.
The cost may be prohibitive so I have to do a lot of consideration. But I think the system will power the 39 ft. fifth wheel toy hauler. May be able to only run 1 AC unit.
Don
Hi,
I find the article misleading. 45 watts is not going to do much more than maintenance charging on any decent sized battery bank.
If, on the other hand, one wishes to keep the battery bank charged up between trips, as little as 12.5 watts per 100 amp-hours of storage may “do the deed”.
For a really useful system 60 to 150 watts per 100 amp-hours of storage is a good goal.
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jimjan
“Thanks for your blogs. They are technical enough to be interesting but not so technical that I get lost. Please keep writing them so I can learn more.
Billy”
Hi Randy,
Let me echo Billy’s sentiment. My rig’s in storage and not accessible so I can’t go and apply the information to a practical use but, your blog is much like a personal seminar for those of us who need a little help with some of the projects you illustrate and that’s one of the great things about ”camping’.
Professor95
GK,
Yep, dirty solar panels are not as efficient as clean ones. You must remember to clean them when shaded rather than when hot from the sun. The problem is particularly bad during the spring pollen season when rainfall is scant. But, with a factory installed rear ladder as part of the coach and a walk-on roof I find it no big deal to keep them clean. Maybe I should rig up a windshield wiper and washer for them?
Randy (Professor95)
Professor95
Earle,
As you probably know, the 8D is an industrial/marine battery designed in much the same manner as the popular, smaller marine starting/trolling batteries. It is not a true deep cycle since it’s plate design allows for high current output for starting as well. The 4D is the half size version of the 8D.
In the past I have used 8D batteries as deep cycle replacements with considerable success, being able to recharge them from a dead (10 volt) state to full charge several hundred times.
“If” I were confronted with your situation I would not swap out the house battery until it is 3-4 years old or beginning to show signs of failure (rapid discharge rate). Then I would replace the house battery with either sealed AGM or open lead-acid golf cart batteries. Replace the battery used for engine starting with the same type you have now. Just be reminded that batteries in series (two six volt) add voltage, not amperage while two 12 volt batteries in parallel add amperage, not voltage. 6 volt golf cart batteries are designed for up to 500 deep charge cycles and can endure the bounce and vibration an RV introduces while moving. They are typically about 220 amp hours each.
Randy (Professor95)
Earle Hasney
We have an Allegro Diesel motor home. It has an 8D Battery for the Chassis and an 4D Battery for the coach. I wonder whether I should change the coach battery to a deep cycle? Earle
GK
Something I’ve heard about roof-mounted panels (from a friend who has them) is that you have to remember to clean them once in a while. A coating of dust, dirt and grime will reduce their efficiency. His approach is basically to rinse them off with water once he gets to his site to wash off anything that accumulated during the drive.
Professor95
Hey Butterbean,
I have not encountered hail large enough to damage the panels. I guess if hail is big enough to do damage to the panels you might as well figure on a new roof and awning too 🙂
Solar start-up costs can easily run into the thousands for high end pro installed systems. The one I showed is entry level do-it-yourself but still cost effective and efficient. Truthfully, solar on a camper is not about saving money – it is about sustaining a system so you can camp longer and more comfortably.
My panels are BP Solar built in the USA. Not sure where the HF panels are built.
Forest River is offering solar as an option in 2012 on their Cedar Creek line. They already offer inverters. Biggest issue is the majority of campers stop at full hook-up campgrounds so demand is low. Some of the most beautiful places we camp have no hook-ups. Those tethered to a power cord don’t know what they are missing.
butterbean carpenter
Howdy Prof Randy 95,
How do you protect your solar panels from HAIL???? Or is that not a problem where you travel??
Nick Russell sez that solar is okay, but the start up cost is too great… I think I’ll send him this; then
again he doesn’t buy Chinese goods… If solar is so good why don’t the manufacturers offer it as an
option, with controllers, inverters, etc.??
Thank you…..
Billy Bob Anderson
Dr. Randy, Prof, Professor, what ever you are, you made my day.
After I read your blog this morning I went to our CVS drugstore and browsed the magazines. I found the super saver coupon in a Popular Mechanics. I took the coupon to the Harbor Freight on the other side of town and bought a 45 watt solar kit. It is in the driveway making free power right now. I had looked for solar to use with my Jayco TT but all I could find was $700 or MORE for less power. This is a dream come true. I can’t believe I got this for $149.95.
Thanks for your blogs. They are technical enough to be interesting but not so technical that I get lost. Please keep writing them so I can learn more.
Billy