Basic Questions on Solar Install

[freetheheal]

I'm finally getting rid of the generator and looking to install solar. Right now I have a 2000W inverter and 450AH of lead acid batteries. I'm looking at installing (3) 175W panels and an MPPT charge controller. I'd like to run my idea by the forum and make sure I'm not missing something.

My run from the panels to the charge controller is about 25'. From what I've found I should wire the panels in series and run a 10 gauge wire. I'm looking at the Renogy Rover 60 mppt controller and that can handle up to 140V which is well within the parameter of the open circuit voltage of the 175W panels which is 24.3V per panel and allows room for additional panels down the road if the need arises. Does anyone see an issue with this or something that I'm missing?

From the charge controller to the batteries I am going to run 8 guage wire (5') with a 60amp fuse.

And between the solar panels and charge controller I was going to mount a 10amp fuse (the solar panels optimum operating current is 8.62amps).

Does this seem like a good plan so far? Am I missing anything? Thank you for your input and help.

[pianotuna]

freetheheal wrote:
to go with 4 175W panels.

Panels-->combiner box-->DC circuit breaker-->controller-->fuse close to the bank-->battery bank.

[Vintage465]

freetheheal wrote:
Well there are a lot more considerations and opinions on solar than I imagined. What I ultimately decided was to go with 4 175W panels. There will be 2 at the very back on each side of the vent. Then one in front of the vent situated perpendicular to the trailer. And then one more between the A/C and the vent in the middle of the trailer. These will be installed in parallel and running 8awg wire from the panels to the combiner box that is at the front. From the combiner box I'm going to go through the roof and straight down to the charge controller with 4awg. We use the trailer quite a bit in the winter so hopefully this will be enough to let us dry camp without the generator for 4 or 5 days. Right now we can go about 2 days in the winter without the generator.

I'm 3-150w panels to the combiner with #10 then I ran #4 from the combiner to the controller in the pass thru then #2 from the controller to the 4-6v GC batteries. I camp for a week at a time in the dead of winter(18-24 degrees)run the furnace and a cpap. With good sun, some light clouds I'm topped up at 11:00 AM usually. We keep the trailer around 55-60 at night. You should be good

[freetheheal]

Well there are a lot more considerations and opinions on solar than I imagined. What I ultimately decided was to go with 4 175W panels. There will be 2 at the very back on each side of the vent. Then one in front of the vent situated perpendicular to the trailer. And then one more between the A/C and the vent in the middle of the trailer. These will be installed in parallel and running 8awg wire from the panels to the combiner box that is at the front. From the combiner box I'm going to go through the roof and straight down to the charge controller with 4awg. We use the trailer quite a bit in the winter so hopefully this will be enough to let us dry camp without the generator for 4 or 5 days. Right now we can go about 2 days in the winter without the generator.

[Vintage465]

pianotuna wrote:
#8 is overkill for a series install.

So If I go to an MPPT controller with mine and go series my #4 from the combiner to the controller will be serious overkill!:B

[ppine]

Keep your generator as a back up for cloudy and rainy days and days with a lot of power usage.

[glennts]

There are 325W panels that are @ $200 new. REC Solar and Hanwah Q. Peak Duo G7 are about @ 5' x < 4' in size. They would probably fit in the 3 open areas if you utilize that space as others have suggested.

[pianotuna]

BFL13,

Adding a panel makes up for not tilting. That works for series and parallel.

Series is better for wire size and a titch early and later in the day production of power. Probably an insignificant additional amount of energy production. But the savings on line losses are significant.

My ideal system would be 48 volts with 1600 watts of panels and 200 amp-hours (at 48 volts) of SiO2 batteries.

Adding an extra panel won't do much for shading unless there are diodes between every cell. So far as I am aware, only Unisolar did that--and they are long since gone. My panels are 15 years old now and still doing 17 amps (~200 watts), if the battery bank is hungry, or I turn on a heavy draw item.

[2oldman]

BFL13 wrote:
In series the added panel is still going to be at the lowest amps same as the shaded panel; in parallel it could be more panel not in the shade so it does its full amount?

I don't know, but when going solar I think it's best to do everything to avoid shade, not make it a factor in installation.

[BFL13]

I forget the math on this, if I ever knew it--when you add a panel to make up for can't be fixed shading loss, do you do better if in parallel?

In series the added panel is still going to be at the lowest amps same as the shaded panel; in parallel it could be more panel not in the shade so it does its full amount?

[2oldman]

freetheheal wrote:
I'd like to run the panels in parallel because I think I will always be dealing with shade issues from the vent covers.

You will still be losing amps. Or you could ditch the vent covers.

[ppine]

Hang on to your generator.

[BFL13]

Yes, move the middle panel at the back to the front. I would choose the right side instead of in the middle and not cover the combiner on the left, but might be a Tv antenna in the way.

[pianotuna]

Hi,

Can you rotate the vents so the lids "open" away from the panels?

Can you raise the panels up 4 inches? This will allow them to cool on the bottom side, while reducing possible shading from the vents.

Can the two "outside" panels be scooted back to the very edge of the roof, and moved to the very side of the roof?

Can the middle panel be moved forward and placed in a transverse manner between the A.C. shroud and the vent?

Or can the panels be staggered between the front vent, and AC. Another in the middle behind the AC shroud. The third panel at the very end of the roof? (this is what I would consider with 3 panels).

Another solution is to add one more panel. (this is what I would do).

. Vent

xxxxx
panel
xxxxx

. AC

xxxxx
panel
xxxxx

. vent

pxx.. ..xxp
axx. v .xxa
nxx. e .xxn
exx. n .xxe
lxx.. t ..xxl

[freetheheal]

I've been trying to think about this and I could use some additional input. I've attached a rough layout of my trailer roof and how I would like to mount the panels. I prefer to mount them at the rear for two reasons.

1. I am trying to keep as much weight to the rear as possible

2. The least amount of obstructions are at the rear to shade the panels. The A/C is the big one I'm trying to stay away from.

I'm thinking I will run #8 wire from the panels up to the front of the trailer. They will enter a combiner box at this point and #4 wire will go from the combiner box to the charge controller. This distance will be about 12'. I'd like to run the panels in parallel because I think I will always be dealing with shade issues from the vent covers. What are some things I should be thinking about with this setup...?