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electrical:solar:gentle_intro [2023/05/11 10:40]
frater_secessus [rack mounting] 		electrical:solar:gentle_intro [2025/04/10 10:27] (current)
frater_secessus [What about flexible panels?]
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 > "...trying to take the comfort level you had in a house into your mobile life [is] tough to do for a boondocker." -- akrvbob((http://www.cheaprvliving.com/forums/Thread-Too-much-or-too-little-Solar?pid=116253#pid116253)) (Bob from Cheap RV Living) > "...trying to take the comfort level you had in a house into your mobile life [is] tough to do for a boondocker." -- akrvbob((http://www.cheaprvliving.com/forums/Thread-Too-much-or-too-little-Solar?pid=116253#pid116253)) (Bob from Cheap RV Living)
  
- 
-> The fastest way to bring beginner expectations of solar in line with reality is to **assume you will run //nothing// off an inverter**.   -- secessus 
  
 > Setting up solar that //works// is easy.  Setting up solar that //works well// and //under challenging conditions// is much tougher.  -- secessus  > Setting up solar that //works// is easy.  Setting up solar that //works well// and //under challenging conditions// is much tougher.  -- secessus 
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   * Making //some// power from solar is easy.    * Making //some// power from solar is easy. 
-    * Making //sufficient power// from solar to cover your [[electrical:12v:dailypowerrequirements|daily power needs]] is much harder. +    * Making //sufficient power// from solar alone to cover your [[electrical:12v:dailypowerrequirements|daily power needs]] is much harder. 
-    * Making sufficient power from solar to cover your daily power needs //in all conditions, seasons, and locations// is so difficult and expensive that few attempt it;  instead we [[electrical:12v:alt_and_solar|augment solar with other forms of charging]].+    * Making sufficient power from solar alone to cover your daily power needs //in all conditions, seasons, and locations// is so difficult and expensive that few attempt it;  instead we [[electrical:12v:alt_and_solar|augment solar with other forms of charging]].
   * panels rarely make their rated output under real conditions   * panels rarely make their rated output under real conditions
 +  * solar makes power as needed.  If there is no user or charging demand solar will twiddle its thumbs, waiting
 +  * your //location// will have a huge effect on solar harvest
 +  * //time of year// will have a huge effect on solar harvest
   * shade on the panels will clobber output   * shade on the panels will clobber output
   * panels still make some power under cloudy skies   * panels still make some power under cloudy skies
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 Getting //some// power from solar is easy.  Getting //reliable// power from solar alone is challenging (and expensive) because solar harvest is greatly affected by [[electrical:solar:output|real-world conditions]]:  latitude, season, shade, temperature, even battery voltage.  It's bit harsh but you need to hear it early on:  //you won't be getting 100w out of a 100w panel//, and //you won't be getting it for 8 hours a day//.  Getting //some// power from solar is easy.  Getting //reliable// power from solar alone is challenging (and expensive) because solar harvest is greatly affected by [[electrical:solar:output|real-world conditions]]:  latitude, season, shade, temperature, even battery voltage.  It's bit harsh but you need to hear it early on:  //you won't be getting 100w out of a 100w panel//, and //you won't be getting it for 8 hours a day//. 
 A crude rule of thumb might be meaningful solar harvest is possible only when the sun is throwing well-defined shadows on the ground.  A crude rule of thumb might be meaningful solar harvest is possible only when the sun is throwing well-defined shadows on the ground. 
 +
 +Solar must not be shaded;  not by weeds on the the ground or by other objects on the roof.  The panel needs to be the tallest object in the general area.  
  
 [[electrical:12v:alternator|Alternator charging]] helps address these shortcomings of solar charging (and //vice versa//) so it is [[electrical:12v:alt_and_solar|a common combination]]. [[electrical:12v:alternator|Alternator charging]] helps address these shortcomings of solar charging (and //vice versa//) so it is [[electrical:12v:alt_and_solar|a common combination]].
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   * **best-effort** power -  you take what you can get from the sun and [[electrical:solar:rationing|minimize power consumption]] to make do.  No household appliances, at least not often.   * **best-effort** power -  you take what you can get from the sun and [[electrical:solar:rationing|minimize power consumption]] to make do.  No household appliances, at least not often.
-  * **reliable power** - you //need// power to keep insulin refrigerated, keep your external heart bypass machine running, etc.  Prepare yourself for added complexity and/or cost because now you have to worry about harvest under poor solar conditions. +  * **reliable power** - you //need// power to keep insulin refrigerated, keep working remotely, keep your external heart bypass machine running, whatever.  Prepare yourself for added complexity and/or cost because now you have to worry about harvest under poor solar conditions. 
     * **massive solar** - You can still collect usable solar power under very poor conditions if you have [[electrical:solar:overpaneling|a huge amount of panel]].  This may require "maxxing out" your roofspace, tilting the panels, or deploying additional portable panels. Such configurations may be [[electrical:solar:builds#w6|1000w or more]].  One of the pleasant side effects of massive solar is that having //enough panel to meet needs in poor solar conditions// means //lots of bonus power in normal and good conditions//.  You may be able to run [[electrical:solar:nonessential|non-essential loads]] without affecting your battery bank's [[electrical:depth_of_discharge|state of charge]].     * **massive solar** - You can still collect usable solar power under very poor conditions if you have [[electrical:solar:overpaneling|a huge amount of panel]].  This may require "maxxing out" your roofspace, tilting the panels, or deploying additional portable panels. Such configurations may be [[electrical:solar:builds#w6|1000w or more]].  One of the pleasant side effects of massive solar is that having //enough panel to meet needs in poor solar conditions// means //lots of bonus power in normal and good conditions//.  You may be able to run [[electrical:solar:nonessential|non-essential loads]] without affecting your battery bank's [[electrical:depth_of_discharge|state of charge]].
     * **solar + other forms of charging** - Solar can work much better when augmented by [[electrical:12v:alt_and_solar|additional sources of charging]].  It can work so well that less solar might be required and overall cost reduced.     * **solar + other forms of charging** - Solar can work much better when augmented by [[electrical:12v:alt_and_solar|additional sources of charging]].  It can work so well that less solar might be required and overall cost reduced.
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 Con Con
  
 +  * **they have to be deployed in order to work**.  This would seem to be obvious, but setting out portable takes time and effort that humans do not always expend
 +  * portables can be tilted.  
 +      * to seasonal optimal angles/azimuth. "Set it and forget it"
 +      * or turned to face the sun as it moves.  An overlooked downside is that panels that are set up to follow the sun **must follow the sun** throughout the day.  Human intervention required. 
   * panels made to be portable tend to be expensive per-watt.    * panels made to be portable tend to be expensive per-watt. 
-  * **they have to be deployed in order to work** 
  
-On the last point:  many people believe they will [[opinion:frater_secessus:beginner_mistakes#believing_they_will_set_out_portable_panels|set out their portables any time they are stopped]];  far fewer actually do it.  + 
 +On the first point:  many people believe they will [[opinion:frater_secessus:beginner_mistakes#believing_they_will_set_out_portable_panels|set out their portables any time they are stopped]];  far fewer actually do it.  And even if they set them out they are sometimes placed in shade or facing away from the sun.  We must pay attention;  solar is unforgiving. 
  
  
 ===== What about flexible panels? ===== ===== What about flexible panels? =====
  
-Flex panels are very expensive by the watt.  They are a great fit for people who need to mount on a curved surface (boat hull, teardrop trailer, etc) or store/lift a portable.  +Good reasons to use flexible panels: 
 + 
 +  * you need to mount panel on a gently curved surface  (boat hull, teardrop trailer, etc)  
 +  * you need lightest weight for portability   
 +  * you are willing to tolerate higher costs and shorter life to get the above 
 + 
 +Bad reasons to use flexible panels: 
 + 
 +  * because they are "cool" 
 +  * because you saw an influencer use them on Insta/YT 
 +  * because you want to walk on them (you can't) 
  
-Otherwise framed panels are the standard for many good reasons. +Framed panels are the standard for many good reasons.  If you must use flex, consider one of the non-crystalline types (CIGS, amorphous, thin-film, etc).  It is not surprising that solid crystals a few inches wide don't like to flex.  
 ===== How much solar do I need? ==== ===== How much solar do I need? ====
  
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 ==== Why daily? ==== ==== Why daily? ====
  
-Power requirements are calculated **daily** because the solar feeds the batteries((and [[electrical:12v:loads|loads]])) only in daylight.  Then at night the system pulls power back out of the batteries. This is natural rhythm of a solar-powered system. +Power requirements are calculated **daily** because the solar feeds the batteries((and [[electrical:12v:loads|loads]])) only in daylight.  Then at night the system pulls power back out of the batteries. This is natural rhythm of a solar-powered system and the reason why deep-cycle batteries are used. 
  
 A **minimal solar configuration** will  A **minimal solar configuration** will 
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 **Pro:** some of the product selection is outsourced for you **Pro:** some of the product selection is outsourced for you
  
-**Con:** likely could get better quality and better-matched components for less money with DIY.  Packages are often put together by marketing teams instead of engineering or support teams.  +**Con:** likely could get better quality and better-matched components for less money with DIY.  Packages are often put together by marketing teams instead of engineering or support teams and sometimes [[https://mouse.mousetrap.net/blog/2019/11/13/pwm-loves-poly/|the combinations don't work as well as they could]].
  
  
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 It is common to mount framed panels on a rack.  This accomplishes a few things: It is common to mount framed panels on a rack.  This accomplishes a few things:
  
 +
 +[[https://amzn.to/45VXHEC|{{ https://m.media-amazon.com/images/I/51qQl5nwz6L._AC_UY218_.jpg?75}}]]
   * allows the panels to always be deployed    * allows the panels to always be deployed 
   * where they won't fall over, walk off, or be urinated on by loose dogs   * where they won't fall over, walk off, or be urinated on by loose dogs
   * allows underside cooling to minimize [[electrical:solar:output#panel_temperature|heat-related losses]] and re-radiation from superheated panels into the van interior   * allows underside cooling to minimize [[electrical:solar:output#panel_temperature|heat-related losses]] and re-radiation from superheated panels into the van interior
 +  * to keep from drilling extra holes in the roof.  Some vans have rack mountpoints built in and don't require any holes for mounting the rack.  
 +  * at least one hole will be required for solar panel wiring entry;  this is typically routed through [[https://amzn.to/45VXHEC|a weatherproof cable gland]].
 +  * allow changes later; drill new holes in the rack instead of in the roof
  
-Note:  avoid racks with "ladder retainers" or other vertical elements.  [[electrical:solar:output#shade|Partial shading]] is brutal on solar harvest, and //carrying around your own shade// is an "unforced error".  If you have inherited a rack with uprights consider cutting them off. +Note:  avoid racks with "ladder retainers" or other vertical elements.  [[electrical:solar:output#shade|Partial shading]] is brutal on solar harvest, and //carrying around your own shade// is an "unforced error".  If you have inherited a rack with uprights consider cutting them off.  If you can't cut them off mount the panels as far away from the uprights as possible.  If you have a basket the panels need to be on top of (or flush with) the basket instead down inside it. 
  
  
electrical/solar/gentle_intro.1683816035.txt.gz · Last modified: 2023/05/11 10:40 by frater_secessus

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