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electrical:12v:intro [2023/08/24 22:49]
princess_fluffypants Adding Calculation instructions/estimates 		electrical:12v:intro [2024/02/21 13:44] (current)
frater_secessus [higher bank voltages]
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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.+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.  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.
  
 Before you spend money on making/storing power in your vehicle, be sure to leverage other sources: Before you spend money on making/storing power in your vehicle, be sure to leverage other sources:
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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.
  
-==== Daily power requirements ====+==== Real-world(ish) examples ==== 
 + 
 +Here are some very general ideas to get you thinking: 
 + 
 +  * **Trivial to run** off the [[electrical:12v:ports|cigarette lighter port]] //while driving// 
 +     * [[electrical:12v:phone charging|phone and tablet]] charging - can also be charged from a [[https://amzn.to/2WTMOAm|USB battery pack]]. 
 +     * [[electrical:12v:laptop|laptop]] charging 
 +     * <=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 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.  
 +  * **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 
 +      * 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.  
 +      * Small [[food:refrigeration|12v compressor fridges]] -- they use little power and run intermittently 
 +      * laptop charging/use during the day 
 +      * [[hvac:roof_vent|roof vent]] 
 +      * swamp coolers (due to high power fan motors) 
 +      * gaming laptops run off solar during the day 
 +      * charging e-bikes, etc [[electrical:solar:nonessential|during the day]] 
 +  * **Harder and more expensive to run** - substantial ($$$) house power system - 400w of solar, 200Ah+ of battery 
 +      * Larger 12v compressor fridges (especially if they have a freezer) 
 +      * 120v refrigerators off [[electrical:inverter|inverters]] 
 +      * charging/using laptops at night 
 +      * gaming consoles|laptops|PCs 
 +      * charging e-bikes, etc at night 
 +      * Small microwaves when used for <3 minutes per day 
 +        * Power draw is high, but duration is short.  Needs a beefy inverter. 
 +  * **Difficult and very expensive to run** - Massive ($$$$$) house power system - 600w+ of solar, 400ah of [[electrical:12v:drop-in_lifepo4|lithium battery]], alternator charging. 
 +      * Cooking with electricity, which is why we use propane 
 +        * 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]] 
 +      * electric [[food:coffee|coffee makers]], which is why we use propane((see the pattern?)) 
 +  * **Completely 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]]. 
 + 
 +Note:  devices that have [[electrical:12v:wallwart|"wall wart adapters"]] may not require an inverter.  
 + 
 +===== Calculating power, battery, and solar requirements =====
  
-There is no way around it: you must come to grips with **how much power you need each day**.   +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.+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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 "Perfect conditions" solar array wattage with a four-hour peak sunlight charge time: 912 / 4 = **228 watts of solar panels.** "Perfect conditions" solar array wattage with a four-hour peak sunlight charge time: 912 / 4 = **228 watts of solar panels.**
- 
-No one has ever complained about have too much battery capacity or too many solar panels, so rounding up is always a good practice.  
  
 The above calculations are for Lithium batteries; for lead chemistries, you should double both the amp-hour and solar wattage to avoid [[electrical:batterycide|battery murder]]. The above calculations are for Lithium batteries; for lead chemistries, you should double both the amp-hour and solar wattage to avoid [[electrical:batterycide|battery murder]].
- 
-==== Real-world(ish) examples ==== 
- 
-Here are some very general ideas to get you thinking: 
- 
-  * **Trivial to run** off the [[electrical:12v:ports|cigarette lighter port]] //while driving// 
-     * [[electrical:12v:phone charging|phone and tablet]] charging - can also be charged from a [[https://amzn.to/2WTMOAm|USB battery pack]]. 
-     * [[electrical:12v:laptop|laptop]] charging 
-     * <=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]]. 
-  * **Easy to run** off a [[lifestyle:faq_solar_generator|portable power pack]]((which you will have to recharge somehow)) 
-      * fan 
-      * [[https://www.cpap.com/blog/cpap-camping/|CPAP]] - especially with humidification turned off 
-  * **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 
-      * laptop charging/use during the day 
-      * [[hvac:roof_vent|roof vent]] 
-      * swamp coolers (due to high power fan motors) 
-      * gaming laptops run off solar during the day 
-      * charging e-bikes, etc [[electrical:solar:nonessential|during the day]] 
-  * **Harder and more expensive to run** - substantial ($$$) house power system - 400w of solar, 200Ah+ of battery 
-      * Larger 12v compressor fridges (especially if they have a freezer) 
-      * 120v refrigerators off [[electrical:inverter|inverter]] 
-      * charging/using laptops at night 
-      * gaming consoles|laptops|PCs 
-      * charging e-bikes, etc at night 
-      * Small microwaves when used for <3 minutes per day 
-        * Power draw is high, but duration is short.  Needs a beefy inverter. 
-  * **Difficult and very expensive to run** - Massive ($$$$$) house power system - 600w+ of solar, 400ah of [[electrical:12v:drop-in_lifepo4|lithium battery]], alternator charging. 
-      * Cooking with electricity, which is why we use propane 
-        * This includes things like insta-pots, electric stovetops, toaster ovens, larger microwaves, etc 
-      * [[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?)) 
-  * **Completely 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]]. 
- 
-Note:  devices that have [[electrical:12v:wallwart|"wall wart adapters"]] may not require an inverter.  
  
 ===== sources of house power ===== ===== sources of house power =====
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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:
electrical/12v/intro.1692931766.txt.gz · Last modified: 2023/08/24 22:49 by princess_fluffypants

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