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Itinerant1's avatar
Itinerant1
Explorer
Jan 09, 2018

Solar performance #s

I posted some of this on another board and thought it might interest some seeing there are a lot of solar system installs on rv using folks here. Here are some numbers from the past year. Habit from the past of record keeping info for performances and cost. A quick run down of dispersed camping, solar system and performance of system. If you keep records of your system and performance please post. It might help others on what they want with possible expectations.

Dispersed camping
2016 (4/16 - 12/31) 200 days
2017 (1/1 - 12/31) 365 days
Consecutive days dispersed camping as of January 8, 2017 starting 12/23/16 - 381 days, still going.

Using previous 2 years of rving (fulltiming) prior to solar install (4/13/16), RV park cost averaged to $25.00 a day.
443 days of dispersed camping needed for return on solar. System has paid for itself.

States AZ, UT, WY, ID, MT, ND, SD, NV
6,105 miles traveled with 5th wheel

Solar info...
Installed at Starlight Solar in Yuma, AZ last year in the spring.

*12v 500ah (400ah usable) lithium batteries (GBS LFP battery system) http://www.starlightsolar.com/elite-power-solutions-lfmp-battery/index.html
*8 CTI-160 watt monocrystalline solar panels (1,280 watts), 2 in series, 4 sets parallel (37 vmp). Panels lay flat on the roof.
*Combiner box to Magnum PT100 controller
*Magnum 3012 hybrid inverter (3000w).
There is a 7" display monitor and the ME-ARC 50 to read the performance of the system, individual cell voltages/ cell temps. A sub panel was added so everything in the 5th wheel except the water heater is running through the inverter.
Total weight for entire system 500#

This is what the system has harvested since the beginning of the year (2017) by month. Every morning I'll record previous day data from the Me-Arc.

Month ____ KWH_____ Ah to batteries
January___87.3______6,360
February__101.4_____7,410
March_____136.5_____9,950
April_____166.8_____12,210
May_______167.6_____12,260
June______164.2_____12,030
July______174.6_____12,770
August____152.1_____11,150
September_108.0_____7,920
October___90.0_____6,540
November _84.3______6,200
December _94.5______6,710
Total __1,527.3kwh___111,510ah
On/Work hours 4,214.4

*Harvest Total – Displays the total amount of energy in kilowatt hours (shown as KWH) delivered to the batteries.
*AH to Batt – Displays the total amp-hours (AH) delivered from the PT array to the DC system.
*On/Work Time – Displays the number of hours of active production by the PV array.

* Highest daily kwh haversted was on July 21st of 7.4 (740ah) in Idaho outside of Yellowstone National Park.

* Lowest daily kwh harvested was on September 15th of 0.2 (20ah) in North Dakota outside of Theodore Roosevelt National Park. Heavy overcast skies with rain.

In the past year the Honda EU2000i genterator has been used 7 times for 2 hours each time which charges at 100ah rate from the Magnum 3012 inverter/ charger into the battery bank and 3 times for 3 hours each when we ran the air conditioner before heading to higher elevation. Some of these run times where just to exercise the generator.
  • I suggest looking up the word "adjunct"

    99% of the places I used to camp had at least partial shading for a considerable percentage of the day.

    On a beach just north of Puerto Vallarta around seven years ago I was invited to a campfire evening party where the air temperature at 8:00PM was around 55F

    It was a big group. Some folks from British Columbia, others from Alberta and even one from Saskatoon. Friends were from Washington, Oregon, and Idaho. Around 20 people or so were sitting around the fire.

    There was discord. All of them had solar panel charging. One fellow even clad his toy yanker trailer with panels.

    The issue was too high of daytime temperatures inside the rig. Full sun was needed. And some folks had had enough. They were pulling out and heading for an RV park.

    What is seldom discussed in discussions is the heat tolerance or vulnerability of people. Some it seemed get overheated when air temperature climbs to 75F. Many of these folks lived in British Columbia or the wet side of the Cascades in Washington and Oregon.

    I can tolerate heat myself to a point. Humidity is a big factor. But I have seen days with no shade where inside rig temperatures climbed to 105F+ with 70% humidity. I'd like to meet the folks who are convinced those numbers are comfortable.

    Aside from solar panels high in the mountains, I bailed out of my house when temperatures reached 98F at 6,780 feet. The whole tiny town was complaining. I traveled up up up to the top of Tioga Pass, 9945 feet, parked at 10,000 and climbed straight up. My NIST lab mercurty thermometer was registering 91F beside me in my shadow. I moved into the shade of a stunted sugarpine and it was a shock.

    Down here, way way down here, temperatures seldom drop to the sixties. People tend to live around their rig, not in it during the day even parked in the shade. I know of no one who parks in the sun down here.

    So with all due respect, claiming solar voltaics is "The Answer" without qualifying and without caveats can be misleading -- even deceptive.

    The whole picture should be painted. To me the first priority of RV'ing is safety, followed by comfort.

    Heat Prostration For Amp Hours may not be someone's idea of a good trip.

    But kudos on your report.
  • Almot's avatar
    Almot
    Explorer III
    Chum lee wrote:
    about 2pm. They have +-30Kw of fixed solar panels on the roof. With a thin cloud layer at about 10,000 feet (sun visible through clouds) the LCD monitor screen showed the total instantaneous output to be 3kw. Not impressive at all!
    3KW could be what their loads demanded?

    Like I said, my system gets topped up before noon, if there is any sun. At that point batteries are very close to full (more in AGM, less in flooded), and controller output drops to a trickle, except for what loads demand.

    Here is estimated AC output for flat 1.1 KW (for example) in El Centro CA. In line with what I and others observed. You can get estimates for most US cities, based on long-term statistics: http://pvwatts.nrel.gov/.

    Month kWH

    January 150
    February 136
    March 172
    April 178
    May 174
    June 161
    July 158
    August 165
    September 159
    October 151
    November 142
    December 146
  • Last Saturday (1-6-2018) I was in the local ALDI store in Los Angeles at about 2pm. They have +-30Kw of fixed solar panels on the roof. With a thin cloud layer at about 10,000 feet (sun visible through clouds) the LCD monitor screen showed the total instantaneous output to be 3kw. Not impressive at all! I hope the state of California gave them a real good tax incentive to install the system because that day it surely wasn't paying for itself. (the CA residents were) That said, I am a big fan of solar power.

    Chum lee
  • Almot's avatar
    Almot
    Explorer III
    SMKettner in SoCal who doesn't post here anymore, have set an example years ago, when installed 660W and after a season decided to leave his genny home. IMO, applies to most of Southwest, save for A/C run. Back then 660W was considered big. Your 1000W is huge.

    My 500W at Lat 41 in winter harvests almost nothing when it rains, 10AH at best. But, since 10AH is ~1/3 of what I use on some days, and since it doesn't rain often in desert, I'm not worried. That it, not worried that there is no genny to exercise :)...

    Your numbers - downscaled to 500W - agree with what my system "would" harvest if given a chance. The problem is, I'm below its capability most of the time. Controller drops to Float (current-based termination of Absorption stage, not a forceful timer) at noon or earlier. Life is good when it's sunny (and not too hot).

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