As I work through the process of upgrading batteries, either a 4-jar bank of Lithium 100Ah 12V, one 300Ah + a 100 Ah, or two 200 Ah, I'm also researching the addition of more solar panels to the roof of my Class A. My boondocking plans in the years to come require a more serious look at power needs and requirements.Currently, I have 3 - 160W solar panels - 26.1 amps total output, fixed to the roof, a 30A PWM Controller, and have room for up to 4-5 more, depending on configuration. Of course, will need a new Controller if I do so. For the solar wattage I'm considering, some sites have suggested an 80A MPPT Controller. I initially thought a 60A would do the trick, but I was basing that on the total amp output of all panels. I also have a 120W, 5.6A portable.I'm thinking I might be better off using portable panels. As a practical matter, at 100-120W per portable panel, I'd need at least 3, probably 4 to reach my goal. It might make sense to have some of my charging capacity in panels I can move around when shade impedes. I understand some can be hooked together, but then, there's the inconvenience of having to store, set up, and take down 4 folding portable panels. Perhaps just two?I understand each person will have different needs and requirements, but is this a balance some strike, where solar is concerned? Or are there 'druthers out there who swear by one way or the other?As an aside, I have a Trav'ler II mounted to my roof, but have considered picking up a portable sat dish - again, when I find myself in the trees...

I’d get very tired of deploying movable panels every morning, moving them around, storing them to go to town for lunch, redeploying upon return, moving them around and putting away at dusk. Plus I’m usually out exploring during the day while my roof top panels are working. Portables won’t be working. Heavy too. IMO you should add more panels to the roof.

I'd prefer the panels on the roof where I never had to worry about them being stolen. Plus one of my goals is to minimize the number of things I need to set up when I get to camp.

I'd also prefer multiple MPPT controllers so you don't lose all solar if the unit dies on you (been there, done that). Probably would come to the same cost other than the minor one to run another set of wires.

I think a combination of both would be beneficial, especially when your coach is shaded..Sometimes it is just hard to be in the sun all the time and portable lets you get the sun that's just missing your RV..My situation here in the Idaho mountains is camping in the sun is hard to do,so I went with portable panels, although I am thinking of putting atleast one 100 watt panel on the roof..A combination of both seems to be the best option..

Interesting... I'd never given thought to the potential for theft... is this more common than not?

Solar - Permanent mount or portable? | Good Sam Community

20 Replies

obiwancanoli
Explorer
Aug 27, 2020
Pianotuna,

I can appreciate your caveats, and they are worth considering, but, how often might it rain ? I'm less confident about roof panel's usefulness in the shade when, with 1 or 2 portables, I can easily aim at the sun, should the charging be needed. Yeah, the panels are potentially cumbersome, and storing them could be a challenge, but then, if I can store them safely - one already is conveniently tucked away - I would, I think, have only one more to find space for. This could prompt me to seek out panels of a size where I CAN store it conveniently.

It would also be interesting to learn if there's a means of tilting the roof panels from the ground, since climbing on the roof at my age probably isn't the safest approach, but then, securing these panels would seem to require a hands-on approach. Still cogitating this dilemma...

As for the batteries, I'm definitely leaning toward two 200Ah Li's, though I have room for the four wet cells that will come out. Others have suggested keeping all batteries at the same size and Ah...

What I'm needing more clarity on is the panel voltage, why higher might be better, how it would function with existing panels which operate at lower voltage. Mono vs. polycrystalline is also not clear to me, though a little research will solve that... some of which, by the way, suggests an MPPT Controller north of 80 amps for the panel wattage I envision...
vermilye
Explorer
Aug 27, 2020
I also prefer both. With my small trailer, rooftop real estate is limited. I have 2 160 watt panels on the roof & carry a portable 160 watt. Most of the time the rooftop panels meet my needs - around 50 amp hours per day & a pair of 100 amp hour lithium batteries. The portable comes out when parked in the shade, and during December/January in the Arizona desert where even tilting the rooftop panels doesn't make up for the low angle sun & short days.
pianotuna
Nomad III
Aug 27, 2020
obiwancanoli wrote:
As I work through the process of upgrading batteries, either a 4-jar bank of Lithium 100Ah 12V, one 300Ah + a 100 Ah, or two 200 Ah, I'm also researching the addition of more solar panels to the roof of my Class A. My boondocking plans in the years to come require a more serious look at power needs and requirements.

Currently, I have 3 - 160W solar panels - 26.1 amps total output, fixed to the roof, a 30A PWM Controller, and have room for up to 4-5 more, depending on configuration. Of course, will need a new Controller if I do so. For the solar wattage I'm considering, some sites have suggested an 80A MPPT Controller. I initially thought a 60A would do the trick, but I was basing that on the total amp output of all panels. I also have a 120W, 5.6A portable.

I'm thinking I might be better off using portable panels. As a practical matter, at 100-120W per portable panel, I'd need at least 3, probably 4 to reach my goal.

It might make sense to have some of my charging capacity in panels I can move around when shade impedes. I understand some can be hooked together, but then, there's the inconvenience of having to store, set up, and take down 4 folding portable panels. Perhaps just two?

I understand each person will have different needs and requirements, but is this a balance some strike, where solar is concerned? Or are there 'druthers out there who swear by one way or the other?

As an aside, I have a Trav'ler II mounted to my roof, but have considered picking up a portable sat dish - again, when I find myself in the trees...

I would do two 200 amp-hour batteries. 2nd choice would be four 100 amp-hour batteries. I would DEFINITELY NOT do 300 / 100. I would consider one 400 amp-hour, but there is a certain comfort in two jars.

Portable panels are, in my opinion, a pain to store, a pain to set up, and subject to breakage when being moved. They are LARGE. Not too bad as far as weight goes--but wind loading needs to be considered. Do you really want to be out in a wind storm with rain trying to strike camp? Do you really want to have to move the panels off the bed--so you can grab 40 winks after a lovely lunch? There are other reasons to avoid portable panels--however theft is the very least of those considerations.

I still get 17 amps from my 2005 panels (256 watts), at solar noon. That is from a fixed flat install. Theoretically I should only see about 15.5 amps, as the panel voltage is 16.5, on a perfect solar day, with perfectly aligned panels (tracking the sun).

In your shoes, I'd add ALL the panels I could and at the highest voltage. Say 8 panels in series/parallel (4 per string). The panels, after all, are the cheapest part of the system.

Be sure to buy a controller that would allow for more wattage in the future. Why? Because should the panels break--new panels are quite likely to have a higher output.
obiwancanoli
Explorer
Aug 27, 2020
Jayco, the more I think about this, the more I agree with your perspective... I suppose the reality of it is this... IF you're going to have solar, roof mount seems a good way to approach it, for at least SOME of the time, they'll be exposed to sunlight... for example, as ktmrfs suggests in the previous post.

I could opt to adding one more panel to the roof, but I think I'd also opt to have an additional portable - two I can deal with. But I might switch out my 120W for a 200W I found, and have another 400W portable, or another Zamp panel at 180W, which could add up to 30+ amps. That, plus the roughly 31 on the roof should be more than sufficient for my anticipated needs...
ktmrfs
Explorer II
Aug 27, 2020
obiwancanoli wrote:
Interesting... I'd never given thought to the potential for theft... is this more common than not?

probably camped well over 100 days with our portable panels, never any hit of any growing legs. But it is a possibility. In reality in 60+ years of camping our family has never had anything taken.

On OP topic I have three 160W panels on the roof and three 160W portable panels. Most often the trailer is pretty well shaded during the day, so portable really helps. couple that with efficiency of a flat panel (poor) vs an angled portable (ability to be near optimum during the best part of the day). But the roof panels do charge while driving down the road. Fixed and portables are on their own controllers.
obiwancanoli
Explorer
Aug 27, 2020
Interesting... I'd never given thought to the potential for theft... is this more common than not?
jaycocreek
Explorer II
Aug 27, 2020
I think a combination of both would be beneficial, especially when your coach is shaded..Sometimes it is just hard to be in the sun all the time and portable lets you get the sun that's just missing your RV..

My situation here in the Idaho mountains is camping in the sun is hard to do,so I went with portable panels, although I am thinking of putting atleast one 100 watt panel on the roof..A combination of both seems to be the best option..
phemens
Explorer
Aug 27, 2020
I'd also prefer multiple MPPT controllers so you don't lose all solar if the unit dies on you (been there, done that). Probably would come to the same cost other than the minor one to run another set of wires.
dedmiston
Moderator
Aug 26, 2020
I'd prefer the panels on the roof where I never had to worry about them being stolen. Plus one of my goals is to minimize the number of things I need to set up when I get to camp.
Lwiddis
Explorer II
Aug 26, 2020
I’d get very tired of deploying movable panels every morning, moving them around, storing them to go to town for lunch, redeploying upon return, moving them around and putting away at dusk. Plus I’m usually out exploring during the day while my roof top panels are working. Portables won’t be working. Heavy too. IMO you should add more panels to the roof.

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Solar - Permanent mount or portable?

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