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electrical:solar:gentle_intro [2023/09/26 00:10] frater_secessus [rack mounting] |
electrical:solar:gentle_intro [2025/06/23 15:28] (current) frater_secessus [solar ready] |
> "...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) |
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> The fastest way to bring beginner expectations of solar in line with reality is to **assume you will run //nothing// off an inverter**. -- secessus | |
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> 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 | * 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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* **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. |
Con | Con |
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| * **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** | |
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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. |
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===== What about flexible panels? ===== | ===== What about flexible panels? ===== |
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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: |
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| * 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 |
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| Bad reasons to use flexible panels: |
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| * because they are "cool" |
| * because you saw an influencer use them on Insta/YT |
| * because you want to walk on them (you can't) |
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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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==== solar ready ==== | ==== solar ready ==== |
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RVs that are sold as "solar ready" typically have a connector and wiring from Zamp. It is more apt to call it "Zamp solar kit ready" as normal panels cannot be attached to the Zamp port. Here is [[https://www.forestriverforums.com/forums/f221/a-frame-solar-ready-71071.html#post740529|Zamp's description of Solar Ready]], which uses panels with built-in controllers. | The "solar ready" feature in RVs is often just an external [[https://en.wikipedia.org/wiki/DC_connector#SAE_connector|SAE]] port wired directly to the house battery bank (no solar charge controller controller). In this scenario panels with built-in solar charge controllers are required. Check polarity before attachment; some vendors (Zamp, infamously) wire them in reverse configuration from common usage. |
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| Example: [[https://www.forestriverforums.com/forums/f221/a-frame-solar-ready-71071.html#post740529|Zamp's description of Solar Ready]], which uses panels with built-in controllers. |
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It is been judged harshly by some users: | It is been judged harshly by some users: |
> “Solar Ready” doesn’t mean sh*t. It means there is a plug wired to your battery and oh by the way IT IS WIRED EXACTLY BACKWARDS. The polarity on the Zamp SAE style connector is reversed. -- John's Tech Blog((https://www.hagensieker.com/wordpress/2020/01/12/rockwood-a122-two-year-review/)) | > “Solar Ready” doesn’t mean sh*t. It means there is a plug wired to your battery and oh by the way IT IS WIRED EXACTLY BACKWARDS. The polarity on the Zamp SAE style connector is reversed. -- John's Tech Blog((https://www.hagensieker.com/wordpress/2020/01/12/rockwood-a122-two-year-review/)) |
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| Normal panels could be used if a solar charge controller were spliced in between the port and bank. |
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| Higher-end "solar ready" setup might include MC4 connectors and entry gland on the roof with appropriate wiring leading to the battery tray area. Add panels and controller of your choice. |
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===== rack mounting ===== | ===== rack mounting ===== |
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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: |
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| [[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 | * 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. |
* allow changes later; drill new holes in 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 |
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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. |
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