Large Solar Panels on a FWC

You should consider based on you wanting to stay in place for days in marginal conditions - sun angle, shade - a standard size panel on the roof and add a folding portable panel that you place away from the truck in the sun at the optimum angle. It seems like this could take best advantage for charging. An outside plug linking the portable to the battery is easy to install.
 
ski3pin said:
You should consider based on you wanting to stay in place for days in marginal conditions - sun angle, shade - a standard size panel on the roof and add a folding portable panel that you place away from the truck in the sun at the optimum angle. It seems like this could take best advantage for charging. An outside plug linking the portable to the battery is easy to install.
Click to expand...
This is how I did portable/stand-alone panel with outside plug:

gallery_2431_103_52034.jpg


This was before I added the roof panels.
I don't bring the stand-alone panel with me anymore...though I could if I wanted to sell power, I guess. ;)
 
I can see the benefit of the portable solar panels and facing them toward the sun. However, I want something simple that will work without effort and something that wont take up space in the camper or my truck. Right now I think the 160 watt panel on the roof will get me what I want. I am going to try and develop a simple mechanism to tilt the panels on the roof to get as much out of the system as possible. I hope that even not tilted and at higher latitudes in the winter, the 160 watt panel will still have no problem charging the batteries.

I've got some thoughts on mounting them to the Yakima racks that will allow them to swivel/tilt up on one side by using the round bars of the rack as the hinge point. My wife is a SketchUp master so I'll see what we can come up with.
 
During the summer my roof mounted panel does just fine. Its in the off season when I really notice how much better my portable panel performs being able to aim it at the sun. In addition to sun angle and shade there fewer hours of sun to achieve a charge in the winter.
 
I'd like to say something for new buyers lurking....

As Pvstoy points out, capacity is a personal thing according to ones usage. I stand by the fact that solar panel size has a point of diminishing return. It's fun, I get that, heck I even went through the math of covering my top and installing a Glacier Bay DC air conditioning / refrigeration unit. But why? Are we four wheeling to work on systems or enjoy nature. Another thing I considered is over sizing solar capacity and cutting back on storage. Now you are saving weight and and appropriately cycling the battery. Makes sense, but the replaced weight though less is higher. Everything is a trade off, but what brought us to FWCs in the first place? For me, simplicity and keeping it lite to negotiate uneven ground.

Not only draw, but also output will be different for a given temperature range and latitude. Output is not only affected by sun angle but also by type and installation. For instance a flush mounted panel without proper air circulation behind it will have a diminished capacity when hot. The math is easy. The assumptions are difficult. Being honest with ones self to make those assumptions is frankly the most challenging part of the equation. The one simple fact is most of us are not honest about is how often the truck is running.

For those new buyers lurking, may I suggest starting with FWCs standard system panel and then determine your actual needs based on actual usage. FWC has engineered their systems over time and a large data base of feedback. Most will find they are well served and not require modification. Supplemental solar or other generation will do the trick for most others. For my personal usage, I'd still go with a 3way refer for a whole host of reasons, but that's just me. Others here obviously have different opinions based on their usage. With 95W of solar, like someone else said, sometimes I feel like I could sell power.

Wetting my finger and putting it in the air,.. Bwh4X4 may have it about right for his long duration stay and a DC refer with, 160W? Just an "un-calculated" guess,.. But for others who have not etched it in stone, just consider erring on the side of less is better and then supplement if needed. All we need to do is start the truck. Most of the time, most of us do that anyhow before and without "needing" to charge.

BTW, there are flexible portable panels about the thickness of card stock now that can be rolled up or stored flat anywhere. One can hook em up and aim them directly at the sun when and where it's shinning through the canopy. That's efficiency,.... If you need it? Most of us probably won't.
 
As Pvstoy points out, capacity is a personal thing according to ones usage...
Click to expand...
A LOT of folks on WTW have dc compressor fridges -- so sufficient electrical power isn't a luxury for a lot of us. And it's amazing how much power -- 90 watts -- my laptop charger draws, and if I'm processing photos while still "out there" I need to charge the laptop a lot. Sure, these are my particular needs...but everyone has their particular needs -- which can be greater or less than average.
Sizing the solar capacity for average use only makes sense to me if the downside of running out of power is negligible.

Yes, you can bring along an extra stand-alone solar panel to deploy if/when needed...but it's simpler to me to just have enough -- plenty of -- capacity on the roof all the time. For me, simpler is better.

And you could use your truck as a big generator in the campsite...but I'd rather not. Running the engine for a little while appears to do the job because of the transient higher voltage -- the "surface charge" -- that the battery shows for a while after charging stops. You have to run the engine a LONG time to really charge the battery...and gasoline is too expensive and flows too fast through my 6.8L engine! And then there's the noise and smell -- not my preferred camp experience.

I wonder how much harm -- loss of longevity -- not deep-cycling does to a battery? (I'm asking because I really don't know.)
That is, if a battery rarely gets below, say, 60% of fully-charged does that reduce its lifetime by 10%? 30%? 50%? Is it different for an AGM vs wet-cell?
If it is a big problem -- if it reduces battery longevity by a lot (whatever "a lot" is), I would use a different approach to making the battery cycle more deeply: Rather than undersize the solar panels in order to ensure that the battery drains enough when sun is plentiful -- that is, "undersized" from the standpoint of not having enough power in low-sun-angle winter or high-latitude or clouds or tree-cover, why not just install a simple switch to cut the power from the panels when sun is plentiful and the battery is easily fully charged?

So with an easy way (via a switch) to ensure sufficient deep-cycling while still ensuring worst-case capacity, what's the downside of a large solar system?
Cost? I spent more on gasoline in one trip to the eastern Sierra than I spent on my entire 240-watt solar system, which will last for years of trips.
Weight? The panels weigh 45 lb while the camper weighs >1000 lbs and the truck+camper weighs >8000 lb.


Whatever capacity one thinks they need/want, I wouldn't go though FWC for the solar panel system (even if you decide that you want the same capacity they standard-ly provide). You pay a lot more for their installed option compared to doing it yourself. It's not hard to install a solar system -- I did it and I'm not a handyman at all.

That's what works for me, anyway. :)
 
I've used the solar calculator I found on this site to determine my needs. I've ran a variety of scenarios through it based on staying in a northern latitude in the late fall and also the lower latitudes when it's hotter and each time I do it I come up with a recommended solar panel of 150 to 160 watts. I'd rather put a 135 watt panel on top, but I can only imagine how miffed I'd be at myself if my system couldn't keep up with my usage on a long stationary trip. I don't want the hassle of taking along a generator or having to pack a smaller portable panel. The roof is such a logical and simple place to keep a panel.

I think I'm going to hold off a few weeks on the solar until I get my refrig installed so that I can accurately determine what the usage will be since it'll be the biggest user of amps. Once I get a good handle on the refrig amp consumption I will be able to determine overall per day usage and size my panel accordingly.
 
Well the refrig comes tomorrow (Isotherm Cruise 85) and so do my new Yakima racks. I had the tracks installed at FWC, but held off on the other rack components until now so I could use an REI gift card and our REI dividends. I ended up saving about $250 on the rack components doing it this way.

What I think I'm going to do is hook up the refrig in the camper temporarily to run so I can assess it's amp usage and then go from there on whether to order the 135 or 160 watt panel. Based strictly on 5 lb weight the difference between the two it's not enough for me not to get the 160 watt panel. However, I still want to test the power usage on the refrig before I pull the trigger. I might need to go bigger! ;)
 
Thought I'd post that I have installed the refrig temporarily into the camper while I wait till I get up to FWC so they can cut the exterior vent. I've been running it to see how many amps it uses and in my first full 24 hour run it used, on average, 1.6 amps/hr. It was also 27 degrees this morning when I checked it.

The refrig wasn't cooled down either before hand and I had it set on the highest setting for the first few hours. So, I think pre-cooling it on 110v before I leave and keeping it at a medium setting will easily get me to 1.5 amp/hour easily. I'll update this info once I get another 24 hours on it now that it's cold.
 
Bwht4x4-- My experience with a Solar World 140 watt panel (made in USA), 115 AH AGM battery, and a NovaKool compressor fridge is that the panel provides what I need without worry, but I don't park in the shade for long periods. It does put out decent amperage when it's overcast. The panel cranks. I bought the panel and basic Morningstar charger from the local shop in SLO (Pacific Energy). It eased my mind to have them size charger and fuse for me, and know that I could return any product to them without mailing. Take HandyBob's advice on wire sizing and run lengths (http://handybobsolar.wordpress.com/) Tip: you can get 10 ga landscape lighting wire from the electical supply shop out by the airport to run from your panel to controller and battery. 30' cost me about $8 there as opposed to non-UV garbage from Home Cheapo for five times the cost. It has lots of fine strands and is very flexible and UV rated. I can give you more details on my solar set up, including how I bolted into the Yakima tracks if you are still contemplating your set up (PM me).

One note on battery cycling--from all of the manufacturers' literature, deep cycling reduces battery life.

For lifting the roof, I did the speaker stand thing that others on this forum discovered. It works great and is always out of the way. I find I can lift the roof no problem with just the solar panel, but I need the speaker stand when surfboards are on top.
 
Central Toast,

Will your solar set-up also charge your battery fully each day, in addition to running the refrig? What I'm going to need is panel big enough to run a refrig during the day, but also fully charge my dual AGM batteries so the refrig will run throughout the night.

I'll PM you. I'd like to see your set up some day if you don't mind. I'm in SLO a couple of times a week.
 
It charges the battery fully each day with the fridge running, when parked in the sun. I ran it for a week straight without driving (so no alternator charge) at fridge temps (around 37 degrees) and checked the battery in evenings and every morning before the sun came up. There were a couple of overcast days that week. It was never below 12.7 volts on my multimeter in the mornings and "full" on the FWC charge indicator and Morningstar controller. It was fully charged in the evenings. See http://www.energymatters.com.au/renewable-energy/batteries/battery-voltage-discharge.php for a chart on voltage and percent charge for AGM vs. gel vs. flooded batteries. That test was good enough for me because I'm usually camped in the sun and I end up driving at least every few days on a trip.

Feel free to get in touch and I'll show you how I went about it...putting this system together was definitely a learning experience for me.
 
Central Toast,

Thanks I will. I'm debating what to do right now for a solar panel. I'm tempted to make my own portable out of two 100 watt panels but I also really like the idea of the panel on the roof and one thing less for me to lug around and have to set up.

I'll PM you to see what your schedule is during the week.

Thanks
 
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