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electrical:12v:intro [2023/08/24 22:55]
princess_fluffypants Moving sections around 		electrical:12v:intro [2024/12/24 09:58] (current)
frater_secessus [avoiding beginner mistakes] added further reading
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 ====== Powering your vanlife ====== ====== Powering your vanlife ======
  
-Making, storing, and using power wisely is important for happy vandwelling. Power issues can seem overwhelming and confusing;  this article intends to lay out the basics. 
  
-Before you spend money on making/storing power in your vehicle, be sure to leverage other sources:+===== TL;DR ===== 
 + 
 +  * There is //chassis power// (your van's electrical system) and //house power// (your power setup for charging and running things).  They are separate except when intentionally combined, as when charging from the alternator. 
 +  * As with money, //using power// is much easier than //making/storing power//. 
 +  * Only you can know how much power you will require;  there will be math. Luckily it is the kind of arithmetic we learned in grade school. 
 +  * it is easy to make //some// power offgrid.  It is challenging to make substantial power, and/or to make it consistently in all conditions.  
 +  * house power systems are DIY (made from selected components) or pre-made ("power stations", "solar generators").  Regardless of your choice, ensure you understand your own needs, ability to charge, and capabilities((specs)) of the products you are considering.   
 + 
 + 
 +[[opinion:frater_secessus:pareto|about these summaries]] 
  
-  * plugs at your work, church, or anywhere else you visit regularly 
-  * plugs at cafes and restaurants -- ask for a table near an outlet 
-  * look for outlets at bus stops, park pavilions, etc.   
  
-It may be useful to carry a gym bag with a power strip, extension cord, and any items that need to be charged.  The power strips allows you to charge many things at once, and the extension cord helps you reach faraway outlets or outlets in inconvenient places (on a wall,  behind furniture).  
  
  
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 Only you will know that, because only you will know what kinds of electrical [[electrical:12v:loads|loads]] you need (or want) to run.  Unlike a wall socket in a house where you can run pretty much anything you want, **using power you make off-grid is a series of choices and compromises**.   Some things are easy to run off-grid;  some things are harder and require more infrastructure, planning, and money. Some things are impractical in campervans.  Car-dwelling presents [[rv:car#power|additional power challenges]] due to limited space and charging methods. Only you will know that, because only you will know what kinds of electrical [[electrical:12v:loads|loads]] you need (or want) to run.  Unlike a wall socket in a house where you can run pretty much anything you want, **using power you make off-grid is a series of choices and compromises**.   Some things are easy to run off-grid;  some things are harder and require more infrastructure, planning, and money. Some things are impractical in campervans.  Car-dwelling presents [[rv:car#power|additional power challenges]] due to limited space and charging methods.
 +
 +See [[electrical:12v:dailypowerrequirements|daily power requirements]]
  
 ==== Real-world(ish) examples ==== ==== Real-world(ish) examples ====
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      * <=100w loads from [[https://amzn.to/3u4Qm1g|small inverters]].  Note that most small, inexpensive inverters are [[electrical:inverter#modified_sine_wave|modified sine wave]] and not appropriate for all [[electrical:12v:loads|loads]].      * <=100w loads from [[https://amzn.to/3u4Qm1g|small inverters]].  Note that most small, inexpensive inverters are [[electrical:inverter#modified_sine_wave|modified sine wave]] and not appropriate for all [[electrical:12v:loads|loads]].
      * very small loads (like a cellphone) might be run off the ciggy/USB port [[https://www.reddit.com/r/urbancarliving/comments/v42jvw/is_it_safe_to_charge_your_phone_in_car_while_its/ib5k2u5/|without the engine running]].      * very small loads (like a cellphone) might be run off the ciggy/USB port [[https://www.reddit.com/r/urbancarliving/comments/v42jvw/is_it_safe_to_charge_your_phone_in_car_while_its/ib5k2u5/|without the engine running]].
-  * **Easy to run** off a [[lifestyle:faq_solar_generator|portable power pack]]((which you will have to recharge somehow)) +  * **very small loads**  like phone charging can be run off [[https://amzn.to/47X2Ziy|USB power bricks]].  See [[https://www.youtube.com/watch?v=G1sjqaRll2s|this testing video]] by Project Farm.  Recharge the brick[s] from the cigarette lighter while driving, at cafes, etc.  
-      * fan+  * **Easy to run** off a small [[lifestyle:faq_solar_generator|portable power station]]((which you will have to recharge somehow)) 
 +      * Phone/Tablet/small laptop (MacBook Air, Chromebook) charging while parked 
 +      * Fan 
 +      * Small 12v LED lights
       * [[https://www.cpap.com/blog/cpap-camping/|CPAP]] - especially with humidification turned off       * [[https://www.cpap.com/blog/cpap-camping/|CPAP]] - especially with humidification turned off
 +      * Note:  there are power stations available in all the sizes described below.
   * **Average loads** - small ($) house power system:  Example:  200w of solar and 100Ah of battery.    * **Average loads** - small ($) house power system:  Example:  200w of solar and 100Ah of battery. 
       * Small [[food:refrigeration|12v compressor fridges]] -- they use little power and run intermittently       * Small [[food:refrigeration|12v compressor fridges]] -- they use little power and run intermittently
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   * **Harder and more expensive to run** - substantial ($$$) house power system - 400w of solar, 200Ah+ of battery   * **Harder and more expensive to run** - substantial ($$$) house power system - 400w of solar, 200Ah+ of battery
       * Larger 12v compressor fridges (especially if they have a freezer)       * Larger 12v compressor fridges (especially if they have a freezer)
-      * 120v refrigerators off [[electrical:inverter|inverter]]+      * 120v refrigerators off [[electrical:inverter|inverters]]
       * charging/using laptops at night       * charging/using laptops at night
       * gaming consoles|laptops|PCs       * gaming consoles|laptops|PCs
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         * Power draw is high, but duration is short.  Needs a beefy inverter.         * Power draw is high, but duration is short.  Needs a beefy inverter.
   * **Difficult and very expensive to run** - Massive ($$$$$) house power system - 600w+ of solar, 400ah of [[electrical:12v:drop-in_lifepo4|lithium battery]], alternator charging.   * **Difficult and very expensive to run** - Massive ($$$$$) house power system - 600w+ of solar, 400ah of [[electrical:12v:drop-in_lifepo4|lithium battery]], alternator charging.
-      * Cooking with electricity, which is why we use propane +      * [[food:cooking:excess_power|Cooking with electricity]], which is why we use propane 
-        * This includes things like insta-pots, electric stovetops, toaster ovens, larger microwaves, etc+        * This includes things like insta-pots, electric stovetops (resistive or induction), toaster ovens, larger microwaves, etc
       * [[hvac:solar_ac|air conditioning]], which is why [[camping:snowbirding|we go where it is cooler]]       * [[hvac:solar_ac|air conditioning]], which is why [[camping:snowbirding|we go where it is cooler]]
       * electric [[food:coffee|coffee makers]], which is why we use propane((see the pattern?))       * electric [[food:coffee|coffee makers]], which is why we use propane((see the pattern?))
-  * **Completely Impossible** unless you're on shore power +  * **Effectively Impossible** unless you're on shore power 
-      * Heating the van. //Tens of thousands// of dollars in lithium batteries will barely last a day of running an electric heater. Which is why we use [[hvac:heating|propane or diesel]].+      * Heating the van with electric space heaters. //Tens of thousands// of dollars in lithium batteries will barely last a day of running an electric heater. Which is why we use [[hvac:heating|propane or diesel]].
  
 Note:  devices that have [[electrical:12v:wallwart|"wall wart adapters"]] may not require an inverter.  Note:  devices that have [[electrical:12v:wallwart|"wall wart adapters"]] may not require an inverter. 
  
-==== Calculating daily power requirements ====+===== Calculating power, battery, and solar requirements =====
  
 The following is a guide to calculate battery storage and solar needs. **Be honest** about what loads you want/need to run and how long you plan to run them. You can also check out [[https://faroutride.com/van-electrical-sizing/|Far Out Ride's sizing guide]] and [[https://faroutride.com/van-electrical-calculator/|their load calculator]] if it's more your style. Remember that you can supplement/substitute the solar system with DC-DC charging from your alternator and/or shore power. The following is a guide to calculate battery storage and solar needs. **Be honest** about what loads you want/need to run and how long you plan to run them. You can also check out [[https://faroutride.com/van-electrical-sizing/|Far Out Ride's sizing guide]] and [[https://faroutride.com/van-electrical-calculator/|their load calculator]] if it's more your style. Remember that you can supplement/substitute the solar system with DC-DC charging from your alternator and/or shore power.
  
-No one has ever complained about have too much battery capacity or too many solar panels, so rounding up is always a good practice. +A general guide is to have **200w of solar for every 100ah of 12v lithium battery**. No one has ever complained about have too much battery capacity or too many solar panels, so rounding up is always a good practice. 
  
 === Calculating your battery size ===  === Calculating your battery size === 
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   * **Calculate your //total// daily draw** in watts by adding the individual watts for each device together.   * **Calculate your //total// daily draw** in watts by adding the individual watts for each device together.
     * Assuming you'll be utilizing a 12 volt LiFePo4 battery bank and wanting a 25% buffer to protect the longevity of your battery bank, use the following equation to get your minimum battery bank capacity in amp-hours: (total daily watts * 1.25) / 12.      * Assuming you'll be utilizing a 12 volt LiFePo4 battery bank and wanting a 25% buffer to protect the longevity of your battery bank, use the following equation to get your minimum battery bank capacity in amp-hours: (total daily watts * 1.25) / 12. 
-      * Jot the result down down -- **this is the minimum battery bank capacity in watts** (or watt-hours, Wh, if you want to be pedantic) that you'll need to power your devices for a single day.+      * Jot the result down down -- **this is the minimum battery bank capacity in amp-hours** that you'll need to power your devices for a single day.
  
 === Calculating Solar Size === === Calculating Solar Size ===
  
-Solar panels only operate at "peak capacity" for approximately four to six hours per day. The amount of solar power your panels can capture will depend on the angle of the panels to the sun, cloud cover, temperature, latitude, dust on the panels, etc. The amount of time you'll spend capturing that solar power will depend on latitude, season, weather, etc. +Solar panels only operate at "[[electrical:solar:output|peak capacity]]" for approximately four to six hours per day. The amount of solar power your panels can capture will depend on the angle of the panels to the sun, cloud cover, temperature, latitude, dust on the panels, etc. The amount of time you'll spend capturing that solar power will depend on latitude, season, weather, etc. 
  
 As a general estimate, assuming ideal weather conditions, but worst-case charging time, **divide the result of your minimum battery bank capacity by four**. This result shows how many total watts of solar you'll require to fully charge your battery bank each day.  As a general estimate, assuming ideal weather conditions, but worst-case charging time, **divide the result of your minimum battery bank capacity by four**. This result shows how many total watts of solar you'll require to fully charge your battery bank each day. 
  
 The chances of getting the full yield out of your panels are slim to none. In the North American winter, for example, you might only get up to 50% of your panel's rated max wattage even on a clear day. The chances of getting the full yield out of your panels are slim to none. In the North American winter, for example, you might only get up to 50% of your panel's rated max wattage even on a clear day.
 +
 +For a more exact estimate based on time/place, see [[electrical:solar:pvwatts|this article on solar harvest modeling]].
  
 === Putting it all together === === Putting it all together ===
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 Most campervans use [[electrical:solar:gentle_intro|solar]] combined with another charging source, usually the van's [[electrical:12v:alternator|alternator]].   [[electrical:12v:alt_and_solar|This combination]] can be both cheap and highly effective((Isolators are inexpensive, and the combination allows one to run much smaller solar configurations than if one were charging by solar alone)) Most campervans use [[electrical:solar:gentle_intro|solar]] combined with another charging source, usually the van's [[electrical:12v:alternator|alternator]].   [[electrical:12v:alt_and_solar|This combination]] can be both cheap and highly effective((Isolators are inexpensive, and the combination allows one to run much smaller solar configurations than if one were charging by solar alone))
  
-^                                                   ^ Pro                                                                                                                                           | **Con**                                                                                                                                                                                                                       | +Before you spend money on making/storing power in your vehicle, be sure to leverage other sources: 
-| [[electrical:shore_power|shore power]] (outlet)   | cheapest per watt \\ simple \\ abundant power                                                                                                 | often not available \\ if available you are tied to the outlet by your cord/adapter \\ campgrounds with outlets are more expensive                                                                                            | + 
-| [[electrical:solar|solar]]                        | automatically makes power when the sun shines \\ makes high voltages needed to fully charge lead-acid batteries\\ silent\\ lasts for decades  | most expensive per watt \\ can be complex\\ panels are large\\ [[electrical:solar:output|output]] drops dramatically [[electrical:solar:shading|when shaded]]                                                                 | +  * plugs at your work, school, church, or anywhere else you visit regularly 
-| [[electrical:12v:alternator|alternator]]          | automatically makes power when driving\\ about 1/10th the cost of solar for the same current output                                           | relatively low charging voltage((unless [[electrical:12v:b2b|b2b]])) \\ can result in [[electrical:12v:psoc|chronic undercharging]] \\ should not idle to charge \\ most people don't drive enough to fully charge lead-acid  | +  * plugs at cafes and restaurants -- ask for a table near an outlet 
-| alternator ([[electrical:12v:ports|ciggy port]])  | available on all vehicles                                                                                                                     | typically limited to 10A (120-150w, see [[electrical:12v:alternator#isolator_without_a_house_battery|this end-around]]).                                                                                                      | +  * look for public outlets at bus stops, park pavilions, etc  
-| [[electrical:generator|generator]]                | can make 1000w+ of 120v \\ can run for days \\ inverter models are quieter                                                                    | can be expensive ($1000+) \\ maintenance \\ needs to be stored when not in use\\ noisy \\ not allowed in some areas/times                                                                                                     |+ 
 +It may be useful to carry a gym bag with a power strip, extension cord, and any items that need to be charged.  The power strips allows you to charge many things at once, and the extension cord helps you reach faraway outlets or outlets in inconvenient places (on a wall,  behind furniture). An inexpensive, pocket-sized [[electrical:shore_power#power_testers|outlet tester]] can quickly tell you if the outlet is live and wired correctly. It's easier to pop one of those in than to drag out all your equipment only to find out there is no power to that outlet.  
 + 
 + 
 + 
 +^                                                   ^ Pro                                                                                                                                           | **Con**                                                                                                                                                        | 
 +| [[electrical:shore_power|shore power]] (outlet)   | cheapest per watt \\ simple \\ abundant power                                                                                                 | often not available \\ if available you are tied to the outlet by your cord/adapter \\ campgrounds with outlets are more expensive                             | 
 +| [[electrical:solar|solar]]                        | automatically makes power when the sun shines \\ makes high voltages needed to fully charge lead-acid batteries\\ silent\\ lasts for decades  | most expensive per watt \\ can be complex\\ panels are large\\ [[electrical:solar:output|output]] drops dramatically [[electrical:solar:shading|when shaded]]  | 
 +| [[electrical:12v:alternator|alternator]]          | automatically makes power when driving\\ about 1/10th the cost of solar for the same current output                                           | can result in [[electrical:12v:psoc|chronic undercharging]] of lead-acid\\ should not [[rv:idling|idle]] to charge\\ pulling wire can be challenging           | 
 +| alternator ([[electrical:12v:ports|ciggy port]])  | available on all vehicles                                                                                                                     | typically limited to 10A (120-150w, see [[electrical:12v:alternator#isolator_without_a_house_battery|this end-around]]).                                       | 
 +| [[electrical:generator|generator]]                | can make 1000w+ of 120v \\ can run for days \\ inverter models are quieter                                                                    | can be expensive ($1000+) \\ maintenance \\ needs to be stored when not in use\\ noisy \\ not allowed in some areas/times                                      |
  
 [[electrical:12v:alt_and_solar|Alternator & solar charging]] enhance each other when used together.  Adding alternator charging to solar can significantly reduce [[electrical:solar:sizing|the amount of solar required]] to meet your needs. [[electrical:12v:alt_and_solar|Alternator & solar charging]] enhance each other when used together.  Adding alternator charging to solar can significantly reduce [[electrical:solar:sizing|the amount of solar required]] to meet your needs.
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 ===== higher bank voltages ===== ===== higher bank voltages =====
 +
 +
 +
    
 Although 12v house banks are most common there are use cases where higher bank voltages (24v, 48v, etc) may be desirable: Although 12v house banks are most common there are use cases where higher bank voltages (24v, 48v, etc) may be desirable:
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   * when someone stumbles into a great deal on a higher-voltage pack (Leaf battery fell off a truck)   * when someone stumbles into a great deal on a higher-voltage pack (Leaf battery fell off a truck)
   * when the vehicle has a 24v alternator, as found in some commercial vehicles like buses or box trucks   * when the vehicle has a 24v alternator, as found in some commercial vehicles like buses or box trucks
 +  * when wiring and solar charge controller expenses need to be reduced
  
 Challenges: Challenges:
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   * requirement for higher solar array voltages.   * requirement for higher solar array voltages.
  
 +
 +===== avoiding beginner mistakes =====
 +
 +  * hoping, wishing, or daydreaming instead of doing the math
 +  * failure to consider //all// loads
 +  * belief that electrical outlets will be easy to find and free to use
 +  * failure to consider the time it takes to recharge a bank
 +  * relying on marketing rather than product specifications
 +  * DIY:  belief that all components have to be from the same brand
 +  * Pre-made:  belief that a "power station" is the default solution to every answer.  People were vandwelling for decades before power stations were invented and marketed.
 +
 +===== further reading =====
 +
 +  * [[https://www.youtube.com/@RVelectricity|RVelectricity YT channel]] (Mike Sokol)
  
  
electrical/12v/intro.1692932123.txt.gz · Last modified: 2023/08/24 22:55 by princess_fluffypants

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