Configuring Rooftop Solar for my Bigfoot th

[Civilguy]

Originally Posted by Jane P.

Another possibility is to find some business or acquaintance where I can plug in the trailer.

One thing I can’t get my head around is whether 3-4 100 watt panels covering the most of the roof would more efficiently harvest sunlight [on cloudy days] than 2 larger panels covering only one section.

Eventually, I will need to address mounting considerations - especially if I decide to get the heavier panels. I am interested that your panels were bolted onto the roof.

Five hours sounds like a full charge, perhaps reflecting the full capacity of your deeper-discharge battery. I was merely looking to supplement perhaps 25-amp-hours in an hour when the solar comes up short.

I know very little about solar, but my understand is that an array's capacity is limited by any cells or panels that are in the shade. I'm not clear on what happens when they are all equally shaded, as on cloudy days.

https://www.infiniteenergy.com.au/sh...ar-pv-systems/

Our factory-installed panel is mounted in the traditional style with an aluminum framework on standoffs. I'm sure that this is very problematic from the standpoint of aerodynamics. I understand it is elevated to provide cooling under the panel. One of my intended future projects is to try and mitigate the drag, perhaps by fairing the frame, but I haven't really worked out a plan. A quick web search indicates that I wouldn't be the first to try improving the airflow around the frames.

[Jane P.]

Originally Posted by John in Santa Cruz

I get 4-5 years out of a pair of $90 each Costco golf cart batts, which have had plenty of power for everything I've needed combined with my 160W solar. every 6 months or so, I have to check the water level, current pair that are ~ 3 years old are just about due for their first water add..

I can buy 10 of these pairs for the cost of a pair of battleborns. please explain this 'substantial savings' ?

It’s easier to post this video:

https://youtu.be/Rp8Hspi4BC4


Impressed that you get 4-5 years between replacements! I had to replace my batteries much sooner.

One 100ah lithium battery replaces both of your golf carts. And it’s cleaner & more efficient than lead acids. My Battleborn is a little longer than a led acid & weighs half as much. It does not produce gases & can be safely installed in the trailers cabin. And you can pair an older lithium with a brand new one. Not so with lead acid batteries. So if I decide to add a 2nd battery two or three years down the road, I do not have to upgrade my current battery.

If I sell my trailer, I can take the lithium with me to my new trailer.

The decision to go lithium was an easy decision for me because I was basically starting from scratch. The trailer I purchased was not set up for boon docking. I needed 2 acid lead batteries for my CPAP machine, and would have had to reconfigure my Bigfoot’s tongue compartment to accommodate a second lead acid. I definitely wanted to install a rooftop solar system. So installing a lithium battery satisfied both my short term & long term needs.

In 2-3 years when your golf carts need replacement, you should seriously think about lithium. Battleborn has reduced it’s prices. They currently offer special upgrades to Escape travel club members. I suspect you can purchase a new lithium for even less money 2-3 years from now.


Confucious 101: Friends don't let friends use lead acid

[Jane P.]

Originally Posted by Civilguy

Five hours sounds like a full charge, perhaps reflecting the full capacity of your deeper-discharge battery. I was merely looking to supplement perhaps 25-amp-hours in an hour when the solar comes up short.

I know very little about solar, but my understand is that an array's capacity is limited by any cells or panels that are in the shade. I'm not clear on what happens when they are all equally shaded, as on cloudy days.

https://www.infiniteenergy.com.au/sh...ar-pv-systems/

Our factory-installed panel is mounted in the traditional style with an aluminum framework on standoffs. I'm sure that this is very problematic from the standpoint of aerodynamics. I understand it is elevated to provide cooling under the panel. One of my intended future projects is to try and mitigate the drag, perhaps by fairing the frame, but I haven't really worked out a plan. A quick web search indicates that I wouldn't be the first to try improving the airflow around the frames.

Hi Mike,

I do believe we are on the same page. Because I know so little about solar, I’ve initiated this thread to seek out advice as well as articulate my thought processes. Kind of like a work journal.

Very informative link - thank you. I read a similar solar related article which stated that, because we’re not living in an ideal world, you need to assume you will be loosing 1/3rd of your battery’s capacity every day and plan to recharge ever 3-4 days.

My trailer roof doesn’t have many shade free areas big enough to accommodate solar panels. For instance Placing a solar panel to adjacent to my AC cover could shade that panel. It’s a tall roof, and I don’t think using bracket system to adjust the angle of the frames is practical for me.

Yes, I was stating 5 hours to completely recharge the battery. Lithium does recharge faster than lead acids. The DC-DC charger would help recharge the battery on longer drives, especially at night. But it is not a reliable solution when remaining at the same location.

Per my research, I plan using aluminum frames. I’ll ask the manufacturer & my installer about ways to mitigate drag with the initial install.

[Jane P.]

Originally Posted by BernieMac13

Hello!

Just thought I'd share what we have on our new Scamp 16!

We purchased 2x Renogy 100 Watt 12 Volt Monocrystalline solar panels

We mounted with VHB and Eternabond tape on the roof. The no-holes install is amazing, and we've driven in freezing and very hot and humid weather, and while checking these every single day, haven't found a single problem!

even though these panels are smaller and more efficient, it may have been a tough sell to get two more of these installed on our roof

We've been considering a bracket system to get these mounted at an angle and adding more

We also have the Victron Energy SmartSolar MPPT 100V 30 amp 12/24-Volt Solar Charge Controller (Bluetooth)

I love Will Prowse's videos, and his word is the gospel for us when it comes to RV electrical!!

In terms of recommendations, 1 battery may be enough, 2 will obviously be better! And if you can swing it, get the 400W of panels, it will definitely help with recharging on cloudy days.

Avoid shade, of course, but worst case, find a plug or drive to a dump station to get that bit of juice in the battery until the next sunny day.

Happy camping!

I am so trying to assure myself that a no holes install would be safe, and what combination of materials work best. I need to evaluate if 200 watt panels, weighing 26.5lbs and 10 lbs more than your 100 watt panels, are good candidates for “no hole install”.

Flexible panels are tempting, but I think the technology has a way to go.

As you can see from my picture, the Bigfoot 21’s rooftop is very limited. My bathroom & cabin fans have rooftop covers. Plus I have a tallish AC cover. I would be hard pressed to put four, “shadow free” 100 watt panels on that roof.

I’ve installed the Victron 712 and appreciate the Bluetooth connection.

The Victron controller I’d my preferred choice. But I can live with another controller if I purchase a kit.

I need to move the trailer every few days to fill up my fresh water tank & dump my gray & black water tanks. That does help.