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electrical:solar:gentle_intro [2018/10/17 08:46]
frater_secessus [charge controller]
electrical:solar:gentle_intro [2019/09/24 13:31] (current)
frater_secessus [daily power needs]
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 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.
  
-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.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.  ​
  
-**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"​.
  
 **[[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))
 +
 +===== first things first: ​ daily power requirements =====
 +
 +It's not fun but the first step in getting solar is to assess **daily power requirements**. ​ It's like writing down all your monthly expenses when making a family budget. Unpleasant but necessary. ​  
 +
 +Power requirements are assessed as **daily** because solar power feeds the batteries((and [[electrical:​12v:​loads|loads]])) only in daylight. ​ Then at night the '​dweller pulls power back out of the batteries. So a **minimal solar configuration** will meet your daytime needs then get you through the night without running out of power. ​  No one but you knows how much power you will need daytime and nighttime. ​
 +
 +==== AC, DC, Amps, and Watts ====
 +The basic idea is to tally up all the [[electrical:​12v:​loads|loads]] you want to run daily, the time in hours each will run, and the amount of power (Watts) each will consume while running.  ​
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 +It is useful to calculate power use in Watts, because "watts are watts" no matter if it's a 12v load or a 120vac load.((inverter inefficiencies will be addressed later)) ​  
 +  * AC (household) devices will usually give consumption in watts on a label.  ​
 +  * DC devices may give watts, but more commonly show Amps on a label. ​ From this we can derive watts: ​ Amps from the label times voltage (12v) == watts
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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.
  
 ===== how solar power works ===== ===== how solar power works =====
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 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 ==== 
- 
- 
-First things first: ​ Bill needed some idea of [[electrical:​solar:​sizing#​your_daily_power_needs|how much power he actually needed each day]]. ​ 
- 
-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. 
  
  
-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 themThis 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 compromise50% DoD is about 12.2v for lead-acid chemistries.  A [[electrical:​12v:​lvd|Low Voltage Disconnect]] can help prevent deeper, damaging discharge.
  
 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:
  
   - fits on your roof   - fits on your roof
electrical/solar/gentle_intro.1539791193.txt.gz ยท Last modified: 2018/10/17 08:46 by frater_secessus