Adding a 3rd mobile panel

[champdog]

Thanks for all the replies in my other post. I stated I was going to purchase the 120w suitcase kit. Well after alot of reading and learning from all here on this site Ive changed direction. I DID purchase 2 100w panels and a 40amp mppt charge controller. I now want to set it all up so I can add a third mobile panel. I have a breaker between the panels and the controller. My thinking is to wire an sae pigtail from the breaker where the panel wires are bolted to it, and run the sae pigtail into one of the outside compartments so I can plug my mobile panel into that. Any thoughts?

[Almot]

What I meant was that there is no need to tilt vertical South-facing panels in winter.

There is no single solution for everybody. For the OP, in open spaces of Ca... If there is a room on the roof for that 3rd panel, why not do just that. With the 4th panel added as portable IF they decide they need it.

In a leafy shade they might want a portable to augment the total harvest, but then a single 100W won't add much and a couple of them will be twice as much of pre- and post- camping preparations. Also, in a partial shade I would go for parallel wiring.

When Santa Ana winds suddenly come blowing down canyons, the sound of portable panel falling on its face is loud enough to wake you up.

[Tom_M1]

By pulling two pins on each panel they can be tilted in place or removed.

[Almot]

Tom_M wrote:

Hey, this is a cheating 🙂
Portable panel you should store inside wet or dusty, carry in and out, fold-unfold the frame, hook-unhook the cables.
I like the idea though. In winter a vertical panel will work same well as 45 degrees tilted.

[Tom_M1]

Almot wrote:
2 reasons:
1) They are (usually) less efficient per sq ft, i.e. 100W flexible is larger than 100W rigid.
2) More difficult to make a frame to hold it in tilted position. To rigid you just bolt 2 hind legs of alum angle or PVC pipes.

I would also think that they are less durable, there is no glass, they use some clear film on top.

But they can be a good choice for roof mount on expensive MH where you don't want to drill any holes. I'm talking about flexible that you can roll out, not those that come with rudimentary metal trim around the perimeter and can "flex" but not roll out. You probably bought the latter type - with metal trim.

I am one that favors the portable solution. I have three panels, two of which are portable. One of my portable panels is a 180 watt flexible which I framed with aluminum channel. My 125 watt glass panel which is on the roof weighs 27 pounds and my 180 watt flexible panel weighs 12 pounds. I mounted my portable panels on the side of my coach. If that side of my coach is toward the sun I can leave them attached, otherwise I remove them and place them on the ground. I've had my flexible panel for three years and it is still working well. Flexible panels are actually more efficient than similar glass panels.

Solar Blvd. is selling a 120 watt flexible panel for $119.
https://www.solarblvd.com/products/solar-cynergy-flexible-bendable-120-watt-12-volt-solar-panel/

Their 120 watt flexible produces about 15 watts per sq ft. Their 140 watt monocrystalline glass panel produces about 13 watts per sq ft.

The flexible panels are very durable and should be stiff enough to use without a frame. About the only down side is a much shorter warranty.

My install. 80 watt on the left, 180 watt flexible on the right:

[Almot]

hedge wrote:
Why would a flexible panel be a poor choice for portable?

.
2 reasons:
1) They are (usually) less efficient per sq ft, i.e. 100W flexible is larger than 100W rigid.
2) More difficult to make a frame to hold it in tilted position. To rigid you just bolt 2 hind legs of alum angle or PVC pipes.

I would also think that they are less durable, there is no glass, they use some clear film on top.

But they can be a good choice for roof mount on expensive MH where you don't want to drill any holes. I'm talking about flexible that you can roll out, not those that come with rudimentary metal trim around the perimeter and can "flex" but not roll out. You probably bought the latter type - with metal trim.

[hedge]

Why would a flexible panel be a poor choice for portable? I ask because that was my plan but haven't done it yet. I did buy the panel so I guess I'm stuck with it but it seemed to me it would work great being lighter.

I was thinking of just leaning it against a tree or maybe even hanging it on the clothes line that we often have up. I have a truck camper so space is tight so I thought it could be stored under the mattress when not in use.

This for me is a 4th panel as I have 3 already mounted on the roof.

[Almot]

In your another thread there was a suggestion to run a cable thick enough, and place controller NOT in the closet. I would do just that.

Time to come out of the closet. What controller do you have? They are all sensitive to overheating. Some will also screw your voltages up, because the temperature sensor is inside the controller instead of having remote sensor on the battery.

[champdog]

Thanks for that!! Im in a class B+ thats 25ft bumper to bumber. Just sold a 33ft 5er. Wanted something small and easy this time. Real estate on the roof is limited but looked at it today and I can fit two more panels up there so maybe 400w is the way Ill go. Bought the 40a so I could expand. I have another thing Im struggling with, Where to mount the charge controller. The only place I have inside the MH thats within a couple feet of the batteries is in a small closet. The xantrex 600w inverter is already in there. Wondering if it will get too warm in there. Other options would be 12' run of wire to the rear outside bay or a 16' run of wire to a wall towards the front of the coach. CC says max 8awg wire to the batteries. How long of a run can I get away with? Are controllers too heat sensitive to put in a 12w x 48h closet with the inverter? Thanks!!!!!!!!!!!!!!!!!!!!!

[Almot]

Going in circles indeed. I said this earlier in other thread - flex panels are rarely used, mostly when there are VERY specific installation requirements. Not a good choice for portable.

"Suitcase model" is simply 100W system split into 50+50W with legs, lowER end controller (sometimes total junk, sometimes acceptable) and a piece of crocodile cable from controller to battery (useless cable to you since you will be either parallel wiring it with the other two panels or use a corresponding receptacle on the trailer). For all this, you will pay upwards of $250. Though I recall they sometimes sell only "suitcase", without controller.

You said you already bought 2*100W panels and 40A MPPT for roof install? Should've bought 40A PWM from Grape instead - considering possible shade. Anyway, for adding portable you only need one 100W panel and a piece of PVC for legs. If you buy a suitcase with controller included - it's usually PWM unless you pay more money yet for MPPT upgrade - you won't be able to run it in parallel with your existing MPPT and 2 other panels.

California forest? 🙂 Yeah, in some areas. Members in SoCal prefer covering all the roof with panels and not dealing with portables. Add another 200W on the roof, flat 200W will work the same as one portable 100W tilted at perfect angle to sun (or better). Just make sure all panels are of the same voltage and current (the same applies to single portable panel hooked up to 2 roof panels and MPPT). 40A MPPT can handle 500-600W array, most trailers have enough roof for that. Alright, I'm partial to roof installs...

[champdog]

Thanks, Ya maybe ill rethink the flex panel! Its not gonna be right away. Maybe by then Ill purchase one of the suitcase models!

[westend]

champdog wrote:
THANKS! Ill look into those connectors, they look awsome. I thought Id pick up a semi flex panel because their lite. Ive seen pvc frames or legs, good idea for sure. We boondock quite a bit in the trees. Thought moveable panel would provide extra when the California forest is blocking some of the 200w on the roof. Ive seen some posts with a fuse between the panels and the cc and some without. I thought a shut off switch would be a good idea so just bought a manual reset circuit breaker. tying a pigtail into the pv wires before the cc seemed like its the same as if I bought another set of mc4 y connectors.Thanks again

Good plan except for the flex panel choice. I would think that a smaller, rigid module would be a better choice, less chance of module failure and easier deployment. The only trade-off is weight and there is not enough to worry about with these sized modules.

[champdog]

THANKS! Ill look into those connectors, they look awsome. I thought Id pick up a semi flex panel because their lite. Ive seen pvc frames or legs, good idea for sure. We boondock quite a bit in the trees. Thought moveable panel would provide extra when the California forest is blocking some of the 200w on the roof. Ive seen some posts with a fuse between the panels and the cc and some without. I thought a shut off switch would be a good idea so just bought a manual reset circuit breaker. tying a pigtail into the pv wires before the cc seemed like its the same as if I bought another set of mc4 y connectors.Thanks again

[Almot]

I dislike portable panels for being portable - with all that this entails - but I hear people are happy with Anderson Powerpole connectors for this application. SAE doesn't look serious for anything more than 5W trickle charger.

Now you can go to Home Depot and get a piece of PVC pipe for panel legs. Don't remember the reasons for not getting that 3rd panel up on the roof - hopefully they are valid.

Btw, no breaker is necessary between panels and controller.