Flexible or framed solar panels?

[mlts22]

What would be better to go with to either augment an existing installation or go with a new install? Regular solar panels with frames, or the newer flexible panels that require no holes drilled... just 3M tape/glue and caulk/sealant around the edges of the panels. However, the downside of flexible panels is the less wattage they bring in, the shorter warranties, and the fact that panels with frames usually have an air gap between the panel and the van, which provides shade and insulation.

[avanti]

I think it is a straight tradeoff between aesthetics and functionality. Of the considerations you mention, I suspect that the air gap is the most significant. PVs work MUCH better when cool, they say.

[booster]

Like Avanti says, form vs function. If you look at the specs on the rigid panels, their ideal mount is several inches off the roof, as they know they want to keep them as cool as possible. I have always wondered about the wind baffles folks like Roadtrek put in the front of panels, I would think, depending on wind direction, they could also make the panels run hotter when parked. With the flexible you also lose the ability to have them all horizontal, as they follow whatever surface they are on.

[Davydd]

You gotta quit watching the Wynns. there are other ways to mount flexible solar panels. I have a custom manufactured flexible solar panel system. Each panel is 140 watts (x 3). They are mounted on an ABS type plastic and trimmed out with a aluminum frame. The assembly is flexible enough to sit on top of the Sprnter roof ribs and span and follow the crown of the roof for a low profile appearance yet be more than an inch off the roof. The assembly is gutter attached and you have to look closely to see the edges. The crown provides positive drainage and the clearance keeps them cooler than direct roof attached. Each panel is zoned in half so partial shade does not affect the whole panel. Each panel also has its own MPPT controller. I saw the three mounted inside the cabinetry box that encloses the Outback inverter. From what I understand the panels are European and not any sold by others in the U.S. They are obviously very light weight as there is no glass and rigid assembly involved.

They were underperforming IMO when we were in Arizona. So adjustments were made that did not involve the panels. Now we have a positive gain at the end of the day despite havin a high overhead of almost 10 amps per hour battery drain from inverter on, refrigerator and I think at least three 1000 watt amplifiers and lots of parasitic controllers and idiot lights. We even have a trickle charger Dom the house batteries to the chassis battery. If I shut off the inverter I can save about 4 amps per hour and lose the use of outlets, microwave and AC. But our electric articulated beds also run on 120vac. So I leave it own.

[booster]

Davydd said:

Solar alone on a B could not charge the batteries. My 420 watts of solar on a perfect day will maybe recharge to compensate for the compressor refrigerator and parasitic energy loss.

Davydd said:

Now we have a positive gain at the end of the day despite havin a high overhead of almost 10 amps per hour battery drain from inverter on, refrigerator and I think at least three 1000 watt amplifiers and lots of parasitic controllers and idiot lights. We even have a trickle charger Dom the house batteries to the chassis battery

.

IMO, 420 watts of solar would be able to support many of the folks with B's, under most circumstances, as your second post indicates.

[wincrasher]

I have 320 watts on my Oliver (glass panels). It's able to keep 400 amp hours topped off without issue. I've never even used 25% of my capacity. To my surprise, they still throw alot of amps even though they are fairly filthy.

As far as the flexible panels go, AMSolar decided not to sell them as they had issues with them cupping and wearing/scratching much like the Wynns have experienced. It's not surprising either, considering the material is not glass, but a plastic.

I don't think the folks at AMSolar did any dancing on their panels either.

[classbbud]

Hi Davydd,
Why were you running your engine generator at ARV Fest? Thanks.

[Highlander]

Aren't the flexible panels more susceptible to scratching? Observed some with scratches amongst the Liveaboard sailing Community.

[Davydd]

Just for the halibut mostly. I never got close to actually needing to. I was there for 5 straight nights boondocking. It would have never kicked on the autogen from what I could estimate. I have autogen set at 25% forgetting that on the percentage readout 25% is actually 0%. So, I thought why not just keep it in the top half percentage wise. We lose about 20% per day max if we don't cook. We weren't even brewing coffee there.

[Davydd]

Originally Posted by Highlander

Are the flexible panels more susceptible to scratching?

I would think so. Glass shouldn't scratch much unless it was raining diamonds.

[classbbud]

Davydd: Thanks for your reply. We are trying to decide between the 800 A hr and 1200 A hr. The 1200 A hr weighs 200 pounds more. I don't think we are the type of travelers that want to move every day. So my thought is it's better to have it and not use it than to not have it and wish we had. Does an extra 200 pounds take a big bite out of the payload?

[Davydd]

classbbud,

I've gone into exhaustive detail as to how I arrived at my decision in the first place to go to 800ah of battery and just recently followed up with my experience. Unless you have an unusual electrical need or think you will use air conditioning a lot I don't think you would ever need more than 800ah. It is all covered in a thread I started called Advancing Alvar in this ClassBForum. Much more than I can say here.

[booster]

Davydd uses a lot of power, so if you have similar usage, and don't like to move often or idle the engine, you may want to get the bigger battery bank. With poor sun, Davydd will be out of power in 3 days of his normal use, maybe even less, IIRC. Even in good sun, it won't keep up and will only buy a little more time. All Davydd's calculations are based on very short stays, so they very possibly wouldn't apply to your desire for longer stops.

You may want to start by comparing what electrical loads you have compared to Davydd, so you can get a feel for how much power you will use per day. I think Davydd is using quite a bit more than the ARV computer program originally predicted, so real world use information can be a good place to start, and then tweak to fit your camping style.

[classbbud]

Thanks Booster. Davydd, do you know what your payload is for Alvar?

[avanti]

Also, note that DavyDD has come to dislike hookups. Obviously, if you usually have shore power during your longer stays, you don't need big batteries.

[classbbud]

Thanks Avanti. I also do not want to use hookups. My main concern is the extra 200 pounds that the 1200 A hr battery will subtract from the available payload.

[stanw909]

You're worried about 200 lbs ? Simply leave wife and her effects at home

[Davydd]

We are getting a bit off topic here. I think I posted my weight in Advancing Alvar. I don't have it handy as I type this. 9,800 lbs or so with tanks filled sticks in my mind. Your additional batteries are 228 lbs plus the additional weight of the enclosed support. You might be looking at closer to 300 lbs. or more.

BTW, I am not aware of any ARV computer program predicting anything. Usage varies among ARV owners. I had only been trying to test to the limits with no regards to conservation. My conclusion is I can easily go a week or about as long as I can go without tank dumping or water filling requiring me to get up and move if I practiced any amount of electrical conservation. One big one would be to simply turn off the inverter when not really needing it. That alone could be as much as 100ah per day. You are paying for an expensive second alternator and high idle option. I've concluded idling is not that bad a thing and would use it if staying some place like BLM land if I wanted to sit. That is another reason I idled at Advanced Fest in the parking lot. Everyone else was doing it and it disturbed no one. I would never do it at the Chisos Basin CG in Big Bend NP for instance. Most likely I will drive someplace and fast charge my batteries anyway even if spending a week in one place.

[Davydd]

My solar is going like gangbusters right now. I have my ARV parked facing east to west so all three of my solar panels are getting optimum sun with little shading. Problem is at home I am plugged into 30 amp service and have full batteries. All that sun is going to waste.

However, last week I had to unplug as I was having my garage re-sided. It sat for 5 days that way and got down to 27% on the battery with inverter turned on but refrigerator turned off. That was a net usage of 438ah (.73 x 600 usable ah). We were in and out of the van all week and I even spent some time watching TV.

[booster]

90ah per day without the inverter or frig, and minimal use. Where is all the power going?