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electrical:solar:gentle_intro [2020/04/13 21:54]
frater_secessus [the easy answer] |
electrical:solar:gentle_intro [2021/02/06 12:41]
frater_secessus [limitations of solar] added other sources |
| ===== how solar power works ===== | ===== how solar power works ===== |
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| Solar power uses [[electrical:solar:panels|solar panels]] to convert sunlight into electricity. This power is usually stored in a [[electrical:12v:deep_cycle_battery|deep-cycle "house" battery]], which is seperate from the vehicle's starter battery. Electricity from the panels is fed to the battery by a [[electrical:solar:charge_controller|solar charge controller]], which keeps the battery [[electrical:12v:charging|optimally charged]] and powers any [[electrical:12v:loads|loads]] (things that consume power). | Solar power uses [[electrical:solar:panels|solar panels]] to convert sunlight into electricity. This power is usually stored in a [[electrical:12v:deep_cycle_battery|deep-cycle "house" battery]], which is separate from the vehicle's starter battery.((unless combined using [[electrical:12v:alternator#isolators|an isolator]], or running a [[electrical:solar:shallow_cycling|single-battery setup]])) Electricity from the panels is fed to the battery by a [[electrical:solar:charge_controller|solar charge controller]], which keeps the battery [[electrical:12v:charging|optimally charged]] and powers any [[electrical:12v:loads|loads]] (things that consume power). |
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| Solar is not a magic bullet; it is a compromise like anything else. **Solar has very high startup costs for the amount of power you get out of it.** It could 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". | Solar is not a magic bullet; it is a compromise like anything else. **Solar has very high startup costs for the amount of power you get out of it.** It could 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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| | More specifically, **solar-only charging** can be unnecessarily difficult and expensive because of the [[electrical:solar:output|many factors]] that can reduce solar harvest. [[electrical:12v:alt_and_solar|Additional sources of charging]] can be added to increase resilience and decrease cost. |
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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. |
| > "...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)) | > "...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)) |
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| The amount of power a solar configuration outputs is [[electrical:solar:output|greatly affected by things like latitude, season, shade, temperature, and even battery voltage]]. | The amount of power a solar configuration outputs is [[electrical:solar:output|greatly affected by things like latitude, season, shade, temperature, and even battery voltage]]. A crude rule of thumb might be meaningful solar harvest is possible only when the sun is throwing well-defined shadows on the ground. |
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| Since it looks like magic, beginners tend to worry about [[electrical:solar:status#is_my_solar_working|whether or not their system is working]]. It usually is. | Since it looks like magic, beginners tend to worry about [[electrical:solar:status#is_my_solar_working|whether or not their system is working]]. It usually is. |
| 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. | 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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| **A peak ahead:** for reasons that will be explained later, this requirement means he will need about 200Ah of lead battery (flooded or AGM)((or 100Ah of lithium)), and 200w+ of solar panel, depending on [[opinion:frater_secessus:panelsizesforinsolation|where the camper will be used]]. | **A peek ahead:** for reasons that will be explained later, this requirement means he will need about 200Ah of lead battery (flooded or AGM)((or 100Ah of lithium)), and 200w+ of solar panel, depending on [[opinion:frater_secessus:panelsizesforinsolation|where the camper will be used]]. |
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| 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. | 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 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. |
