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electrical:solar:gentle_intro [2018/10/17 11:46] frater_secessus [charge controller] |
electrical:solar:gentle_intro [2019/09/24 15:55] frater_secessus [how solar power works] |
This page aims to provide beginners with a basic overview of solar power for nomads. There are oversimplifications and concepts skipped for clarity. If you would like a refresher on basic electronics, see [[https://www.youtube.com/watch?v=eTvXx9tBkuU|the AltE Intro to Electronics for solar]] video. | This page aims to provide beginners with a basic overview of solar power for nomads. There are oversimplifications and concepts skipped for clarity. If you would like a refresher on basic electronics, see [[https://www.youtube.com/watch?v=eTvXx9tBkuU|the AltE Intro to Electronics for solar]] video. |
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A quick definition: the word //nominal// will crop up again and again in your reading, both here and elsewhere. In your head you can replace the word "nominal" with the phrase "so-called". The most common use is "nominal 12v", referring to the common automotive 12v system. The term is used for historical reasons and is almost never literally 12.00 volts. In fact, a lead-acid battery is [[electrical:depth_of_discharge|over-discharged]] at 12.0v! | A quick definition: the word [[electrical:nominal|nominal]] will crop up again and again in your reading, both here and elsewhere. In your head you can replace the word "nominal" with the phrase "so-called". //Nominal// refers to something's name, and the name for car electrical systems is "12v" even though it is very rarely literally 12.0 volts. |
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Solar is not a magic bullet; it is a compromise like anything else. | Solar is not a magic bullet; it is a compromise like anything else. |
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**Solar is expensive for the amount of power you get out of it.** It can cost several thousand dollars to get the same amount of reliable power one might might get from a residential (or campsite) outlet with a $20 extension cord. | **Solar has very high startup costs for the amount of power you get out of it.** It can cost several thousand dollars to get the same amount of reliable power one might might get from a residential (or campsite) outlet with a $20 extension cord. Over time, though, the power is "free". |
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**[[electrical:solar:rationing|Minimizing power consumption]] is key** to happiness with a simple, affordable solar setup. It requires a change in mindset for most folks. Electrical power becomes a precious resource to be carefully consumed. The **path to frustration** (or at least considerable expense) involves [[hvac:solar|heating or cooling with electricity]] or trying to run household appliances in a van. | **[[electrical:solar:rationing|Minimizing power consumption]] is key** to happiness with a simple, affordable solar setup. It requires a change in mindset for most folks. Electrical power becomes a precious resource to be carefully consumed. The **path to frustration** (or at least considerable expense) involves [[hvac:solar|heating or cooling with electricity]] or trying to run household appliances in a van. |
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Given these limitations why do we do spend so much time and money on solar? Because having power off-grid, however expensive and limited, can make a //huge// difference in quality of life. Solar is silent, works for decades, and is always working when the sun is shining.((portable solar only produces when deployed)) | Given these limitations why do we do spend so much time and money on solar? Because having power off-grid, however expensive and limited, can make a //huge// difference in quality of life. Solar is silent, works for decades, and is always working when the sun is shining.((portable solar only produces when deployed)) |
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| ==== daily power needs ==== |
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| First things first: Bill needed some idea of [[electrical:solar:sizing#your_daily_power_needs|how much power he actually needed each day]]. |
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| One way to figure it out is to [[electrical:solar:builds|see what configurations other people are running successfully in their own camper]] right now. The gamut runs from 100W to 1000W+, with 200W being the most common. |
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| The details of Bill's logic and math has been [[electrical:solar:daily-gentle|moved to its own page]], but for now we will stipulate he came up with a daily requirement of **91Ah** of usable battery capacity for each 24hr period. On average he will consume that much power each day, and will have to replace that amount((and a little bit more due to charging inefficiencies)) from the sun. |
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===== how solar power works ===== | ===== how solar power works ===== |
So how did he pick those components? How did he know they would work? Where did he start? [[electrical:solar:builds|What are other people doing?]] How the heck does anyone untangle this stuff?((by mastering small sections at a time!)) | So how did he pick those components? How did he know they would work? Where did he start? [[electrical:solar:builds|What are other people doing?]] How the heck does anyone untangle this stuff?((by mastering small sections at a time!)) |
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==== daily power needs ==== | |
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First things first: Bill needed some idea of [[electrical:solar:sizing#your_daily_power_needs|how much power he actually needed each day]]. | |
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One way to figure it out is to [[electrical:solar:builds|see what configurations other people are running successfully in their own camper]] right now. The gamut runs from 100W to 1000W+, with 200W being the most common. | |
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The details of Bill's logic and math has been [[electrical:solar:daily-gentle|moved to its own page]], but for now we will stipulate he came up with a daily requirement of **91Ah**. On average he will consume that much power each day, and will have to replace that amount((and a little bit more due to charging inefficiencies)) from the sun. | |
==== battery ==== | ==== battery ==== |
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The most beginner tolerant and value-for-money battery bank is two **6v deep cycle "golf cart" batteries** [[electrical:12v:parallel_serial|wired in series]] to make 12v. This will provide 200+ Ah (amp-hours) of rated capacity.((100+ Ah of usable capacity)) This bank gives Bill one normal day's use and and about a half/day of of reserve (ie, a day with no charging). A set of golf carts like this will be sufficient for most needs and does well with 200-500W of solar panel. Deep cycle batteries should be [[electrical:depth_of_discharge|discharged no lower than 50%]] to avoid damaging them. This is about 12.2v. A [[electrical:12v:lvd|Low Voltage Disconnect]] can help prevent deeper, damaging discharge. | The most beginner tolerant and value-for-money battery bank is two **6v deep cycle flooded((you can/must add water periodically))"golf cart" batteries** [[electrical:12v:parallel_serial|wired in series]] to make 12v. This will provide 200+ Ah (amp-hours) of rated capacity.((100+ Ah of usable capacity)) This bank gives Bill one normal day's use and and about a half/day of of reserve (ie, a day with no charging). A set of golf carts like this will be sufficient for most needs and does well with 200-500W of solar panel. Deep cycle batteries are typically [[electrical:depth_of_discharge|discharged no lower than 50%]] as this is a good usability/lifespan compromise. 50% DoD is about 12.2v for lead-acid chemistries. A [[electrical:12v:lvd|Low Voltage Disconnect]] can help prevent deeper, damaging discharge. |
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Yes, they should be vented. No, not everyone does. | Yes, they should be vented. No, not everyone does. |
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Considering the solar panels themselves, there are framed panels ([[electrical:solar:panels#monocrystalline|mono]], [[electrical:solar:panels#monocrystalline|poly]]), and semi-flexible ([[electrical:solar:panels#thin_film|amorphous]]) panels. Buy whatever: | Considering the solar panels themselves, there are framed panels ([[electrical:solar:panels#monocrystalline|mono]], [[electrical:solar:panels#monocrystalline|poly]]), and semi-flexible (mono, poly, or [[electrical:solar:panels#thin_film|amorphous]]) panels. Buy whatever: |
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- fits on your roof | - fits on your roof |