Solar panels on roof?

Discussion in 'Off Grid Living' started by JRR, Dec 5, 2017.

  1. JRR

    JRR Monkey

    Howdy, y'all.
    I'm looking into getting my house off grid. Currently, I spend more in fees and the minimum charge than I do in the actual electricity I burn. Most months, I'd pay about $45 if I pulled the main breaker for a month. Most months my total bill is about $85. It's a bit more in winter, as much as $100-130, maybe. I heat my house with space heaters at the moment, so that could be even lower.
    Anyways, I live in a wooded area, and the only good place to mount panels in full sunlight is on the roof of the 2nd story. I have joint issues, so I won't be able to get up there to clean them off very often. Fortunately, I live in Alabama, so snow is rarely an issue - maybe once or twice a year on average. There might be an issue with tree sap and bird crap, however. How often will I have to get up there to clean those panels off?

    Gator 45/70 and Dunerunner like this.
  3. Asia-Off-Grid

    Asia-Off-Grid Loving Life Site Supporter+

    Another thing to keep in mind, besides snow, is dust. I live in Cambodia, right off a farm (dirt) road. Over the dry season, dust will really build up on the panels, located on the roof. So, how far off a road are you? Is the road dirt?

    If the dirt road issue doesn't apply, I imagine you would need to clean them, at least, once per quarter. If you start seeing output drop, you may wish to check them as well.

    Also, a lot of videos I see on Youtube, the people install their panels in partially shady, or shady areas. They may not realize that, even if shading only ONE cell on a panel, you will seriously inhibit its output. So, you want as much possible DIRECT sunlight as possible, through the day.
    Tully Mars likes this.
  4. oil pan 4

    oil pan 4 Monkey+++

    Need to know what your electrical consumption is and how much you got to spend.
    There is probably no way you can go off grid with electric space heaters.
    It's cheaper to save power rather than generate your own.
    Gator 45/70 and Bandit99 like this.
  5. ghrit

    ghrit Bad company Administrator Founding Member

    The direct answer is that there's no way to know how often cleaning will be needed without some history. That simply says watch the output, and when it starts to drop off, it's time to look closer. Us olde phartes and those with other physical issues might have a real good reason to buy a drone and hire a (monkey) to do the climbing.

    By now, you know there's a LOT more to solar than buying the panels ---
  6. Seawolf1090

    Seawolf1090 Adventure Riding Monkey Founding Member

    The power loss due to one or a few cells being blocked means more small panels can be better than fewer large panels.
  7. arleigh

    arleigh Goophy monkey

    I built my solar on my shop trailer ,Made it easier to service and move with me when I move, Each panel has it's own wire going to the control panel and it's own switch to test it's out put. same with the wind mill and other 12 volt contributors .
    I am primarily on a battery system and solar is only one part.
    It is advised that you have your batteries as close as possible , and if your converting through inverters, they should be close to the batteries .
    Since my panels are less than 10' off the ground and I live in ranch country it is dusty a lot especially with the wind .
    I often have used a squidgy on a long poll to go over them and that's enough. I don't think a roof two stories high as the same issues. I have never seen any one else cleaning theirs, however moving snow off might be of some concern.
    I dislike heights, especially in slippery conditions and particularly on a roof .
    If I were tasked with cleaning snow off a roof especially 2 stories up I would rig a push broom and ropes and a ridge cap so that passing the rope over the house a partner could pull the rope with the broom up to the peak and I could pull it down over the panels.
    the round ridge cap would both protect the ridge and the rope and make an easy transition moving across the ridge and row of panels.
    My second choice is purchasing boat shrink wrap ,enough to cover the whole set of panels and suspending it in place with ropes, so that during or after the storm ( if it is necessary) give it a good shake and the snow will slide off. snow does not stick to this material.
    I did this covering my truck when/where ever parked in the winter . kept it warmer and ready to go while every one else was scrapping off their wind shields . I closed the fabric in the door jamb so it couldn't be blown away and kept snoopers from peaking in. The material comes in several colors even clear , I strongly recommend not using white in the winter as snow ploughs cannot see the difference if you happen to park in the street. but white is great for protecting other things for the rest of the year.
    This material unlike any other tarp material you can find, and it's uv resistance is unparalleled .
  8. Dunerunner

    Dunerunner Brewery Monkey Moderator

    So, Welcome to The Monkey, JRR!

    What do you heat hot water and cook with?
    Replaced your lighting with LEDs or going 12VDC?

    I would heat with wood, pellets second if wood is undesirable, propane and natural gas or electricity last. There many advantages to Solar Electrical generation, but it requires an investment in equipment to be done right. At your level of utilization of electricity it would cost you more to put up solar than to continue using the utility feed. JMO.
  9. arleigh

    arleigh Goophy monkey

    The electric company takes no responsibility for brown outs ,spikes or black outs, damage to customers equipment .
    My choice to go battery/solar came not for economy of the electric bill, but because the inverter off a battery was safer for my electronics than grid power.
    I built a battery inverter to my home PC using a regular battery charger initially . Later on as I had the money bought a solar panel and added them as I could afford them . I still keep a grid tied battery charger available when the over cast has lasted several days and not enough wind for the mill to compensate. but primarily I am on a "battery system" supplemented by solar and wind and generators if necessary .
  10. JRR

    JRR Monkey

    I don't plan on it. That's just how I'm heating now.

    I'm just in the planning stages, currently. I'm 100% on the grid, atm. I plan on installing a wood stove and a propane stove for cooking. Lights will be LED. I have a 500 watt solar setup on my camper, so I'm not a complete noob to this, just MOSTLY a noob. My consumption will drop way down. I only plan on running a few LED lights, a fridge, a freezer, and some low power electronics - laptop, router, etc. Was thinking of going with 10 of these: EcoSolargy 230 Watt 24 Volt Solar Panel | solarblvd

    My yard is pretty well shaded so the roof is my only option without a LOT of tree clearing that I really don't want to do. But I simply can't be climbing a 24 foot ladder to clean those panels with any kind of frequency.
    Last edited by a moderator: Dec 5, 2017
  11. oil pan 4

    oil pan 4 Monkey+++

    Each 230w panel is only going to produce about 1kwh per day, best case scenario.
    With all gas appliances, high efficiency inverter heatpump air conditioning we were down to about 33kwh per day in summer and 22 to 25 during the brief non heating and cooling season.
    You will also need a generator or 3.
    I have a 7kw and 17.5kw single phase generators and a home made alternator welder/generator that makes about 3kw of DC.
  12. Bandit99

    Bandit99 Monkey+++

    Absolutely no way to set them on the ground? My intent is to do just that, set them on the ground with a tracking unit that will rotate them to remain aiming at the sun for maximum output but...I have a lot of land to use. Even if I don't use a auto-tracker and just rotate them manually, if and when I want, it would be a better solution for me. I just can't see putting them on a roof if you can't get at them to maintain or clean them as they'll be nothing but a headache and probably a bit useless in the winter, dangerous too...but that might be your only solution. I do understand not wanting to cut trees. I spent too damn long in burnt-brown, treeless rock-pile countries to cut my beautiful spruces or ponderosa pines down. Ain't happening. Drives the builders nuts... My problem is snow as I live in Northern Idaho so placing them on the ground is a better solution where they can be easily cleaned.
  13. JRR

    JRR Monkey

    That's way more than I burn. My last electric bill was 399 KWH, and I'm still using AC appliances. I can get by on 1500 watts with the few loads I will have. I sized it up 800 watts just to be sure. I don't need much, and I have a generator I can turn on twice a month to wash clothes and for any sequential days without sun.
    Here's a list off the top of my head of what I need to power:
    Water pump - used very infrequently.
    Refrigerator - 2.5 amp-hours with 30-40% duty cycle
    CPAP machine - 3 amps or so 8 hours a night, if I'm lucky.
    Lights - Might try and get by with 10 watt bulbs, might have to go brighter.
    TV - Mine has been on 3 times this year.
    Microwave - Use a couple times a week for a couple minutes.
    Charge a cellphone, flashlight, drill, etc.
    Lights, CPAP, laptop, fridge, water pump, fan(s) and tv are all dc, inverter will power the freezer and microwave, and anything else needed.
    Generator for washer and dryer
    That's about it.
    Wood stove, propane stove and water heater to round it out.

    My only problem is getting sunlight to the panels. Trees to the south, and west, road is about 75 feet from the house to the north. I MIGHT be able to put them on the bank near the road, but they'd still be shaded in the late afternoon, especially in winter, by the trees to the west, and some idiot might decide to toss a brick at them from the road. I'll look into that and see how much shading they'd be under. The roof would be perfect, if not for maintenance issues.
  14. oil pan 4

    oil pan 4 Monkey+++

    Gas or electric dryer?
  15. JRR

    JRR Monkey

  16. ghrit

    ghrit Bad company Administrator Founding Member

    Your total kwh usage is not the whole story. Your inductive starting loads (reefer, freezer, CPAP. well pump motors) are gonna be your downfall if you don't size the hardware appropriately.
    Asia-Off-Grid likes this.
  17. JRR

    JRR Monkey

    I know this. That's why I started small with my travel trailer to learn all this. My issue is not with sizing the system, but with placement of panels.
  18. Asia-Off-Grid

    Asia-Off-Grid Loving Life Site Supporter+

    Which I addressed, if I am not mistaken?
  19. oil pan 4

    oil pan 4 Monkey+++

    Loose the electric dryer.
    They draw around 24 amps of 240v power. A 7kw generator could barely power it.
    Plus you are going to burn up to a gallon of gasoline to power it.
    Go with a gas dryer since you are already going to have propane. They use about 8 amps of 120v power while the glow coil is going then after the flame lights off amp draw drops to around half that to power the drum motor and blower.
    An unremarkable solar power system could power a gas dryer.
    The gas dryer should burn between 0.5 to 1.5lb of propane. The gas dryer could easily be powered by a smaller generator while that generator is powering other items or charging the house battery.
    Gas dryer amp draw could be further lowered using powerfactor correction an additional 25% to 50% for the blower fan motor.
  20. JRR

    JRR Monkey

    I only use the dryer in inclement weather anyway. I usually hang my clothes. I can just time laundry on sunny days.
    Gator 45/70 likes this.
  21. BTPost

    BTPost Old Fart Snow Monkey Moderator

    Most CPAPs will have a DC Input available, so you can save the Power Supply Conversion Losses... both of ours are that way and run off 12Vdc...
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