How much solar would be needed?

[Dick1142]

I have a 15.5 CF residential refrigerator with a dedicated inverter and 200 watts of solar with 6 6vt batteries. I have found it very adequate for occasional overnighting. I have not tried extended dry camping, but am very happy with this setup. I use very little 12v power otherwise.

[Dranoel]

I have a 25 cf residential fridge and run the generator from 1-2 hrs/day to make up the daily deficit in the spring and summer. But, there are a lot of variables.

[SSG Scott]

Originally Posted by oatmeal

I totally agree. But with the residential refrigerator, you're going to need a pretty good amount of solar--more than you're going to want to have portable panels for.

We dithered on solar for a while, back when it was quite expensive (2005), and finally decided that the deciding factor would be if we wanted to do it, mainly to not have to listen to the generator, and not whether it made financial sense.

We have 1,050 watts flat-mounted on the roof. If we're in the sun, we can go pretty much indefinitely without running the generator, but we have a propane refrigerator. I worked through some numbers and concluded we wouldn't be able to do that if we had a residential refrigerator.

Sure enough, there's a guy who has 1,000 watts of solar on this same type of motorhome, but he has a residential refrigerator and he reports that he runs his generator every 2-3 days, which comports with what my numbers told me.

I ditto the above post as I have 1040 watts of panels on my 28 foot Tiffin Breeze, big wiring to minimize losses, Morningstar TS-60-MPPT controller, Xlink pro battery monitor and love the silent sound of 60 amps of charging power while camping in the woods (20 amps on full overcast days). I too have a propane fridge but switch it over to solar when the batteries are fully charged most sunny afternoons. (draws 30 amps).

It doesn't have to be expensive-1040 watts of panels, Morningstar controller and 12 & 4 gage wiring- $1425 total cost.

[mchero]

Full Wall slide on My rig so I have plenty of space on the roof for 4 255 watt high voltage panels flat! 8 z brackets/panel. No tilting on this rig. I don't have ANY AC units casting a shadow in the late afternoon. I typically point the nose north.
2 strings paralled. Running 60 volts so I can run 12g PV wire with branch connectors so NO COMBINER BOX NEEDED!
I used A simple entry plate just over the closet (left rear) for a super water tight seal. Batteries are also on the left rear so it was a straight shot down. Midnight Solar Classic light 200 connected to my internal network lets me keep a close eye on what's going on.
I replaced the cooked Norcold cooling unit on the 4 door with an Amish cooling unit and VERY glad I did. Did NOT want a residential fridge. Even in 95 to 100 deg temps out here in Quartzsite she keeps her cool.
Running 4 Interstate 220ah deep cycle 6v batteries so i'm around 440ah total. Will U/G the batteries down the road. I could go for weeks w/o running the genset but we do like to watch Dish network via Pathway x2 in the late evening so we run the generator to charge the batts about 2hr.s/night.
We also pump water from the 60 gallon bladder in the back of the jeep, run convection and will sometimes run a load of clothes or two while genset is running (multitasking).
Onan Quiet Diesel 7500 sips the diesel. So glad I don't have a gas or LP genset.

LOVE the boondocking lifestyle out here in LaPosa West With the solar we can run the two vent fans All day. Also, brewing a pot of coffee in the AM w/o the generator is wonderful. We have a mean lean boondocking machine!

[mchero]

The installation of the solar panels was quite simple one person job. I just needed a 2nd person to hand them up to me AFTER I attached 8 z brackets to each panel.

Looking from front to rear you can see three panels, I have plenty of open space to lay the panels FLAT. Note I have ZERO shadowing from any AC units on the roof.



The 4th panel is BETWEEN the two roof AC units. Nose currently pointing south so I have to close the kitchen vents somewhat to prevent a very small shadow from landing on the panel.



Closeup of the Z-brackets. I installed 8/panel. 20K miles and zero movement. Note the sealant under and on top of the screws. No water intrusion what so ever!



In my first post above I stated 12awg PV wire but I stand corrected, 10 awg is what I installed. I'm running 60 vdc thru the PV. You can see some of the branch connectors that I used. 2 strings paralleled. The rear 2 on one string and the two forward on the 2nd string. Did this por possible shadowing BUT if I'm out in the open pointing north or south I have no shadows to worry about.
I used branch connectors to connect the PV wire. I did purchase a bag of MC4 connectors and I also invested in a crimper for the connectors so I'm available to assist in your cabling!

Loose cables need to be tied down but I have about 15k miles of travel with those panels, No chafing or rub marks on the roof so far.



All in all I'm very satisfied with the solar install. I have much more detailed images as well as links on my web page. Please PM me for my PERSONAL web page address.
I did have the address on my signature but was informed by two separate admins here on this forum that I'd have to remove the link or risk getting kicked off the forum. I guess they thought it was a competitors web site just by looking at the name!

NOTE I apologize for the pics displaying sideways.

[oatmeal]

There are lots of threads about solar installations. This thread is about whether someone with a residential refrigerator can get enough solar using portable solar panels to not have to use the generator.

My answer is definitely "no." And even with roof-mounted panels, you're going to have to have much more than the occasional boondocker is willing to invest in, even assuming there's enough roof space.

[mchero]

As stated in the original post; " do very little dry camping now." Perhaps the poster will consider panels on the rooftop in the future?

[CountryFit]

Originally Posted by ScottHelmann

I ditto the above post as I have 1040 watts of panels on my 28 foot Tiffin Breeze, big wiring to minimize losses, Morningstar TS-60-MPPT controller, Xlink pro battery monitor and love the silent sound of 60 amps of charging power while camping in the woods (20 amps on full overcast days). I too have a propane fridge but switch it over to solar when the batteries are fully charged most sunny afternoons. (draws 30 amps).

It doesn't have to be expensive-1040 watts of panels, Morningstar controller and 12 & 4 gage wiring- $1425 total cost.

scott, your controller shows charging at 57.3a. that is awesome. was it taken lately? where are you at? i could only get 40a with 1200w at noon in a sunny day in san francisco now.

[mchero]

Originally Posted by CountryFit

scott, your controller shows charging at 57.3a. that is awesome. was it taken lately? where are you at? i could only get 40a with 1200w at noon in a sunny day in san francisco now.

How about 62.9? Quartzsite AZ panels flat on roof!

Flat on the roof w/o any shadows

Sorry about the PIC being sideways.
4 Gigawatt 255 amp high voltage panels for just about 80c/watt. Just under 1000.00 after a $50.00 pallet breakup fee AND about $70.00 in CA taxes.
Midnight Solar Classic Light 200

I LOVE SOLAR!

[SSG Scott]

Originally Posted by CountryFit

scott, your controller shows charging at 57.3a. that is awesome. was it taken lately? where are you at? i could only get 40a with 1200w at noon in a sunny day in san francisco now.

Checking the date time info on the picture - It was taken on Sunday October 2nd at 10:42 am. It was taken at Stockade lake north campground in Custer State Park, South Dakota.

Wiring size, wiring configuration and wire length in addition to what controller you are using makes a difference. It's all in the details. This photo was taken with a Morningstar Tristar TS-60 PWM controller (not even a fancy MPPT controller). If you want to give me lots of details about your system i might be able to help or we can just hook up together while traveling and see if there is a tweek or two that might get you some of those missing amps.

Note- I did change out the Morningstar Tristar TS-60-PWM controller with a TS-60-MPPT controller last week for testing (as I happened upon a used one at a great price) and am currently datalogging for comparison tests. More to come about that later.

[SSG Scott]

Originally Posted by mchero

How about 62.9? Quartzsite AZ panels flat on roof!

Flat on the roof w/o any shadows

Sorry about the PIC being sideways.
4 Gigawatt 255 amp high voltage panels for just about 80c/watt. Just under 1000.00 after a $50.00 pallet breakup fee AND about $70.00 in CA taxes.
Midnight Solar Classic Light 200

I LOVE SOLAR!

Nice system! Good installation with no shadows! There are some great deals out there on bigger solar panels if you have great space like in your installation! Solar Cells, Solar Panels, Renewable Energy, Wind Energy, Charge Controllers, Solar Trackers - Solarblvd has 320 watt full sized panels like yours for $119. They wouldn't fit on my roof but on an RV like yours it's pretty much awesome! Solar just keeps getting cheaper and cheaper! Nothing like the silent sound of the sun running all your systems!

[pcurt23]

Originally Posted by Scottybdivin

Bill, I am with you. My reason for not boonedocking as much as I would like may be different than yours, since I am still employed. A good portion of my boonedocking is in a warm climate and the need for AC negates the value of solar. However, when we do visit the mountains or high desert and dry camp, it would be nice not to have to run the generator. There's no way I can justify installing solar from a financial standpoint, but the fiddle factor in me make me want to jump all in.

"Fiddle factor" That is great. I call it something different but I have installed AGS, Battery monitor, electric toilet, led lighting all for the same reason. I used the ags once. Go for it.

[mchero]

Scott
I believe the full wall slide had alot todo with the space available on the roof. Nice that the rear ac unit is placed about halfway down the roof.
With the current batteries i wake up to 12.1 volts at around 7am and as soon as the sun hits the panels charging starts around 9 ill fire up the coffee pot. Im able to run the ceiling fans and such throughout the day but come around 4 or so i start backin off on the power consumption. If i had a newer battery bank i could prob. make it thru the night but we like our tv and such so we do run the genset in the
late evening. Thats when we will also run the other appliances like washkng a load of clothes, pump water into tanks or perhaps run the convection. I think the real key to the whole setup is not running the generator at all during the day.
I believe we where running a convection oven when i took the above screenshot. Not all of that power was going into the batteries.

[CountryFit]

both robert's and scott's are impressive!

i have been to custer state park, it's way up north. you even produce more solar than i do! something isn't quite right with mine... here is my set up:

- 5 "sunpower" 240w at 40v panels; flat mounted.
- midnite solar classic 150 mppt controller.
- 700ah li battery pack (have extra 600ah cells already will hook them up soon)
- wires from panels to combiner box is #10
- wires from combiner box to controller is #6
- wires from controller to battery is #4
- panels are parallel connected
- combiner box is on top. the wires go through fridge vent down to the compartment below the fridge then go horizentally to the battery bay.
- the controller is inside of the battery bay
- breaker on each in and out of controller

now in sf bay area, 41a during noon. in summer in mid coast oregon, i have seen 56a the max.

why it does not output as much as desired? i can think of -

1) the panel self. i bought those @60 cents/w from a small shop in phoenix. he fabricated the black frames, no manufacturer's labeling anywhere. he said it's sunpower 240w panel. the size and number of the cells on each panel corresponds to sunpower's spec. now i am not sure.

2) with flat on the roof, i measured the voltages at combiner box - open voltage for each panel is 42v; closed voltage is 38.6v. the controller input voltage is about 37.6v. drop of 1v is expected.

3) my combiner is a diy item - i used aluminum bus bar for positive and negative connections. an inline fuse for positive wire. don't feel that has any problem.

can't think of anything else wrong... can you?