solar panel mounting question
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politics123
Active Member
a bit difficult to answer without knowing how big of an array! Also, are you interested in single-axis tracking or dual-axis tracking?
Besides the "can you," you should also consider "should you."
Panel mounts need to meet the high wind standard in your area (so a hurricane doesn't blow them away) and need to be sturdy enough considering the electrical risks (a 6 panel mount of 24volt panels, connected serially, generates 144v DC... more then enough to kill you, start a fire, etc)
If you're off-grid, have a small low-voltage setup (say, a single 60 watt panel), and are just looking to maximize the power produced, then you can probably mount it to anything or build yourself. Linear actuators or bicycle mounts come to mind. http://hacknmod.com/hack/diy-sun-tracking-solar-panels/
The larger the investment, or the closer to civilization, the more likely I'd choose a commercial product.
Besides the "can you," you should also consider "should you."
Panel mounts need to meet the high wind standard in your area (so a hurricane doesn't blow them away) and need to be sturdy enough considering the electrical risks (a 6 panel mount of 24volt panels, connected serially, generates 144v DC... more then enough to kill you, start a fire, etc)
If you're off-grid, have a small low-voltage setup (say, a single 60 watt panel), and are just looking to maximize the power produced, then you can probably mount it to anything or build yourself. Linear actuators or bicycle mounts come to mind. http://hacknmod.com/hack/diy-sun-tracking-solar-panels/
The larger the investment, or the closer to civilization, the more likely I'd choose a commercial product.
Thanks for the links.
I am thinking to start with four 100W panels, add more later. Each 100W panel is bigger than the K band dish, but not too much. I think DiseQc motor mount probably can handle one 100W panel during windy situation. Right now, solar panels are really cheap. However, look all those roof mount panels, I think they probably produce less than 50% of its rated power, even during peak time of the year. During winter time, those solar panel only probably produce 15% of its rated power during peak hours. If the solar panel can follow sun movement, it probably could get 50% during winter (due to winter sun is not strong enough), and 80% during summer for most part of the day.
I am thinking to start with four 100W panels, add more later. Each 100W panel is bigger than the K band dish, but not too much. I think DiseQc motor mount probably can handle one 100W panel during windy situation. Right now, solar panels are really cheap. However, look all those roof mount panels, I think they probably produce less than 50% of its rated power, even during peak time of the year. During winter time, those solar panel only probably produce 15% of its rated power during peak hours. If the solar panel can follow sun movement, it probably could get 50% during winter (due to winter sun is not strong enough), and 80% during summer for most part of the day.
The little Ku band dish movers would be straining with a 100 watt panel if it gets windy, if you look for and old C- band pole and mount in rural areas you can sometimes get them for the price of removing it. The last C-band dish I had was on a 6" diameter pole and could handle lots of wind load, most mesh 10' dishes were on a 3 1/2" diameter pole and I would think 4 panels would be no problem as long as the pole was installed with enough concrete and and sunk deep enough. I just checked my brothers website and it looks like he has 8 panels per pole for his setup, I think his panels are 135 watts, I gave him some old C- band equipment for mounting his panels but it looks like he either built or bought new mounts. Your panels should make good power in the winter, just not as many hours, in the summer solar panels make less power if they get to hot, in the winter cooler temps help but the lower sun angle on a fixed mount does hurt a bit.
politics123
Active Member
The best theoretical (yet implausible) day for Solar PV (at least, the traditional mono-and poly solar chips) power production is a super-cold, windy, cloudless, smogless day where the sun is perpendicular to the panels for a full 24 hours. Each deviation costs you power production. My system in the Wash, DC area is a flat-panel, 45 degree angle (fixed), facing due south. It tends to produce the most power during the spring or fall... when there's the best combination of cloudless, cold, clear days... and when the sun angle is most perpendicular to my 12/12 pitch roof, even though the length of day is shorter than summer months. I attached a graph below with ~2 years of my actuals.
Trackers will improve power production over flat panels. The question is whether the money spent on trackers, all things being equal, is the best return for the investment. Your 4x100 panelswill cost roughly $500/investment. There are online calculators to help you predict the increase in power production for 1-axis and 2-axis trackers in your area. Most of the claims I see are around 25-30% of single axis trackers, and 30-40% increase with 2-axis trackers. But at what cost and complexity? Automatic trackers cost more to install and setup and have higher ongoing maintenance costs. They are more complex, more prone to break, etc.
For comparison, you can get a 50% increase in power by purchasing 2 additional panels for $250 total and flat-mounting them... and with negligible additional mounting costs (assuming you're already building a 2x4 wood flat-panel mount, making space for 6 panels over 4 is at little marginal cost).
One simple, low cost option for tracking is a seasonal angle adjuster, my guess is it would be good for 10% increase in power production with only a little added complexity. Build a flat panel mount except that you hinge the bottom, and adjust the angle of the unit four times a year.
Tracker Power Production Claims:
http://www.solarinte...ing_systems.pdf
http://www.renewable...ates-more-power
My Solar PV production actuals, 11/1/2010 through 10/31/2012
Trackers will improve power production over flat panels. The question is whether the money spent on trackers, all things being equal, is the best return for the investment. Your 4x100 panelswill cost roughly $500/investment. There are online calculators to help you predict the increase in power production for 1-axis and 2-axis trackers in your area. Most of the claims I see are around 25-30% of single axis trackers, and 30-40% increase with 2-axis trackers. But at what cost and complexity? Automatic trackers cost more to install and setup and have higher ongoing maintenance costs. They are more complex, more prone to break, etc.
For comparison, you can get a 50% increase in power by purchasing 2 additional panels for $250 total and flat-mounting them... and with negligible additional mounting costs (assuming you're already building a 2x4 wood flat-panel mount, making space for 6 panels over 4 is at little marginal cost).
One simple, low cost option for tracking is a seasonal angle adjuster, my guess is it would be good for 10% increase in power production with only a little added complexity. Build a flat panel mount except that you hinge the bottom, and adjust the angle of the unit four times a year.
Tracker Power Production Claims:
http://www.solarinte...ing_systems.pdf
http://www.renewable...ates-more-power
My Solar PV production actuals, 11/1/2010 through 10/31/2012
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Desert_AIP
Senior Member
Why four 100 watt rather than two 200+ watt?
While only the O.P. can answer the question above, there are some good reasons.
1. Small off grid 12 volt system and wants 36 cell panels for battery charging, many
Of the larger panel are designed to be used in a grid inter-tied system and you would
need a MPPT charger to use the panels.
2. Was wanting to use a dish mover designed for Ku band satellite dishes of about 1 meter
In diameter or less and a big 200+ watt panel would not work.
3. Maybe the O.P. found the best price per watt was for 100 watt panels.
1. Small off grid 12 volt system and wants 36 cell panels for battery charging, many
Of the larger panel are designed to be used in a grid inter-tied system and you would
need a MPPT charger to use the panels.
2. Was wanting to use a dish mover designed for Ku band satellite dishes of about 1 meter
In diameter or less and a big 200+ watt panel would not work.
3. Maybe the O.P. found the best price per watt was for 100 watt panels.
Great info...I'm really enjoying this forum.
Politics123 - what size solar array do you have and what would be the cost today for panels and the electronics to connect to a home's panel? I haven't really looked into PV for a few years due to the cost at the time. I did hear the Chinese production of solar panel pushed the costs down but I thought the cost was largely offset by some of the equipment to connect solar to the house/grid became more expensive.
Thanks.
David
Politics123 - what size solar array do you have and what would be the cost today for panels and the electronics to connect to a home's panel? I haven't really looked into PV for a few years due to the cost at the time. I did hear the Chinese production of solar panel pushed the costs down but I thought the cost was largely offset by some of the equipment to connect solar to the house/grid became more expensive.
Thanks.
David
tmbrown97
Senior Member
Great topic - being that I live in an area with power costing $0.42kWh after a low base, I'd love to go solar soon - so I need to learn about mounting on a tile roof safely and doing a grid-tied system. My power bills fluctuate from $380 in the winter to $880 in the summer, so it's a worthwhile investment! However I don't want to just pay someone else $50K to do it; I'd rather have the right inverter and components for a large system, but add panels as time/money permit.
Also I live in a community with an HOA - and while they aren't legally permitted to disallow solar systems, they can implement some restrictions such as which direction they face and how they're mounted. They're only allowed flat - no tracking systems would be permitted... and it's a 2-story with lots of different roof pitches, all of which are nearly 30ft off the ground...
Anyway - that's irrelevant, but I enjoy seeing these topics and the information shared - solar has been of great interest to me for a long time because of the freedom it provides from the utilities and the feasibility of being better than a generator after a major disaster when fuel for your generator may be scarce.
Also I live in a community with an HOA - and while they aren't legally permitted to disallow solar systems, they can implement some restrictions such as which direction they face and how they're mounted. They're only allowed flat - no tracking systems would be permitted... and it's a 2-story with lots of different roof pitches, all of which are nearly 30ft off the ground...
Anyway - that's irrelevant, but I enjoy seeing these topics and the information shared - solar has been of great interest to me for a long time because of the freedom it provides from the utilities and the feasibility of being better than a generator after a major disaster when fuel for your generator may be scarce.
politics123
Active Member
Solar prices have never been less expensive. I put my system up in 2009, and I could do the same now and save at least 30%, if not more.
I have 10.5kw -- 60 suntech 175w panels. As a general rule, you can get panels in the $1/watt range. A professional installation in the $4/watt range turn-key. That's before tax breaks, rebates, pre-paid SRECs, and other incentives. My panels are on a very large 12x12 roof sitting about 30' off the ground... definitely not a DIY job, especially since I also opted for an AC-coupled, critical-loads, battery backup solution. Remember that stand alone grid-tied systems won't produce anything if there's a power outage....
For those of you in the mid-atlantic/north-east, Astrum will quote you a turn-key installation price and run the ROI math for you. Can't speak to the type of work they do, but I do appreciate instant quoting. If you're looking for kits or panels, sun electronics probably has the best prices, especially if you're "local" to their Florida or AZ warehouses.
If you're interested in doing it yourself... and you're on-the-grid, the way to go is probably emphase micro-inverters. You buy one microinverter per panel, so if you have 6 panels, you need 6 inverters. The benefit is no single-point of failure, much better shade/unequal panel output (aka: if you have panels that are facing different directions or different angles), very detailed monitoring, and for small installations, it generally costs less. Oh, and you basically backfeed 240 to your panel, so it's much easier for the electricians. Yeah, I know that many are supposed to be masters of DC power also, but in truth, I bet most master residential electricians rarely see high-voltage DC. I have six strings of 240 volts (or was that 480... can't remember!) DC each... not something to be triffled with.
I have 10.5kw -- 60 suntech 175w panels. As a general rule, you can get panels in the $1/watt range. A professional installation in the $4/watt range turn-key. That's before tax breaks, rebates, pre-paid SRECs, and other incentives. My panels are on a very large 12x12 roof sitting about 30' off the ground... definitely not a DIY job, especially since I also opted for an AC-coupled, critical-loads, battery backup solution. Remember that stand alone grid-tied systems won't produce anything if there's a power outage....
For those of you in the mid-atlantic/north-east, Astrum will quote you a turn-key installation price and run the ROI math for you. Can't speak to the type of work they do, but I do appreciate instant quoting. If you're looking for kits or panels, sun electronics probably has the best prices, especially if you're "local" to their Florida or AZ warehouses.
If you're interested in doing it yourself... and you're on-the-grid, the way to go is probably emphase micro-inverters. You buy one microinverter per panel, so if you have 6 panels, you need 6 inverters. The benefit is no single-point of failure, much better shade/unequal panel output (aka: if you have panels that are facing different directions or different angles), very detailed monitoring, and for small installations, it generally costs less. Oh, and you basically backfeed 240 to your panel, so it's much easier for the electricians. Yeah, I know that many are supposed to be masters of DC power also, but in truth, I bet most master residential electricians rarely see high-voltage DC. I have six strings of 240 volts (or was that 480... can't remember!) DC each... not something to be triffled with.
I brought four 100W panels for their smaller size, so that I can put up an array of Ku band satelite trackers, each turn one panel following the sun during the day. I am not sure I can put a large system in one place, since there are many tall trees around our property, but I could find spots where sun shine can reach all year long. Mounting each 100W panel on a Ku band satelite tracker is also probably cheaper than the roof one by professional installers. I am just not sure if home owner association allowing me to put 4 Ku band tracker with solar panels on the roof. One good thing to put solar panel on roof is that the house will be cooler due to solar panel obsorbed most the sun. I brought solar panel after learning my friend in Long Island lost power for more than two weeks earlier this year.
Like Politics123 pointed out, micro grid tie inveters are cheap these days, if you are lucky, you can get a 300W one for under $100, a 600W for $150. Solar panels are also cheap I saw people selling 1000W (10 x 100w panels) for $1500. But I think the price will go up after new year, since during his election Obama promsed tax more for oversea made solar panels next year.
Politics123 has an very useful result for me to digist. I noticed the morning sun at 10AM is almost 90 degree from 3PM sun in our area. That is why I was thinking using tracker to follow the sun. But his result showing not much different. I am also kind of surprised to learn that winter days producing more power than summer days, since summer days are much longer.
Like Politics123 pointed out, micro grid tie inveters are cheap these days, if you are lucky, you can get a 300W one for under $100, a 600W for $150. Solar panels are also cheap I saw people selling 1000W (10 x 100w panels) for $1500. But I think the price will go up after new year, since during his election Obama promsed tax more for oversea made solar panels next year.
Politics123 has an very useful result for me to digist. I noticed the morning sun at 10AM is almost 90 degree from 3PM sun in our area. That is why I was thinking using tracker to follow the sun. But his result showing not much different. I am also kind of surprised to learn that winter days producing more power than summer days, since summer days are much longer.
I did some experiement with one 100W solar panel, one micro inverter and KillaWatt meter.
I put the solar panel facing the direction of sun toward south with little overcase earlier afternoon.
I noticed the sun is about 40 degree above horizon level. If I had the solar panel tilted 15 degree, KillaWatt reported about 25W.
If I tilted the solar panel 45 degrees, Killawatt reported 50W power generated.
However, building a sun tracker is a much bigger work than I thought. The solar panel, even 100W panel is a lot heavier than a satelite dish.
I put the solar panel facing the direction of sun toward south with little overcase earlier afternoon.
I noticed the sun is about 40 degree above horizon level. If I had the solar panel tilted 15 degree, KillaWatt reported about 25W.
If I tilted the solar panel 45 degrees, Killawatt reported 50W power generated.
However, building a sun tracker is a much bigger work than I thought. The solar panel, even 100W panel is a lot heavier than a satelite dish.
politics123
Active Member
Build It Solar has plenty of information here on all things D-I-Y solar. I saw a few links to home-build trackers:
http://www.builditsolar.com
Here's one of many:
http://www.redrok.com/led3xassm.htm#led3xc3
http://www.builditsolar.com
Here's one of many:
http://www.redrok.com/led3xassm.htm#led3xc3
