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opinion:solar:sizing [2022/03/18 13:56] frater_secessus [overlanding] |
opinion:solar:sizing [2022/05/24 15:10] frater_secessus [generator charging] |
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There are many [[electrical: | There are many [[electrical: | ||
+ | |||
+ | See [[opinion: | ||
===== overall economics ===== | ===== overall economics ===== | ||
- | Solar is relatively expensive when used alone. | + | Since solar is dependent on local conditions one has to size the system to **the worst conditions** |
- | In general bigger systems (higher wattage panels, bigger controllers, | + | In general, bigger systems (higher wattage panels, bigger controllers, |
+ | Broadly speaking, lithium chemistries are most cost-effective when the camping experience is expected to last for many years and the batteries stored inside.((Note that it is false economy to pay for 10 years of battery cycling (as with lithium) if one is going to wreck it in 2 years)). | ||
==== days of reserve ==== | ==== days of reserve ==== | ||
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- | ===== solar panels | + | ===== solar charging |
+ | ==== solar panels ==== | ||
- | The bare-bones minimum for solar, assuming everything goes exactly right, | + | |
+ | |||
+ | The bare-bones minimum for solar, assuming everything goes exactly right, | ||
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- | ===== solar charge controller | + | ==== solar charge controller ==== |
- | ==== controller choice ==== | ||
+ | === controller choice === | ||
- | Most people do fine with a PWM controller. | + | The [[electrical: |
+ | |||
+ | |||
+ | Most people do fine with a PWM controller. | ||
You may **want an MPPT controller**: | You may **want an MPPT controller**: | ||
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- | ==== controller sizing | + | === controller sizing === |
[[electrical: | [[electrical: | ||
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+ | |||
+ | |||
+ | ===== alternator charging ===== | ||
+ | |||
+ | For many people living in vehicles [[electrical: | ||
+ | |||
+ | You will need **some kind of alternator charging** | ||
+ | |||
+ | * if you have no solar | ||
+ | * if you have insufficient solar <-- very common | ||
+ | * if you have AGM, which craves a ton of current in Bulk charging | ||
+ | |||
+ | You will **not need alternator charging** | ||
+ | |||
+ | * if you have [[electrical: | ||
+ | * if you stay on shore power much of the time | ||
+ | * if have solar and most of your driving happens after noon((the isolator contributes best during Bulk, which typically occurs in the morning)) | ||
+ | |||
+ | More expensive [[electrical: | ||
+ | |||
+ | * you have no solar | ||
+ | * current-hungry battery like AGM or lithium threatens your alternator' | ||
+ | * you have a voltage-sensitive battery like gel or lithium | ||
+ | |||
+ | |||
+ | ===== generator charging ===== | ||
+ | |||
+ | |||
+ | |||
+ | You may need a generator if: | ||
+ | |||
+ | * you need to run big loads like A/C | ||
+ | * you have a lithium battery bank but camp in long stretches with minimal solar. | ||
+ | * you have enough solar to [[electrical: | ||
===== battery bank ===== | ===== battery bank ===== | ||
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Having an **oversized lead bank** for your charging ability results in [[electrical: | Having an **oversized lead bank** for your charging ability results in [[electrical: | ||
- | IMO, it is better to have an undersized bank you can charge //fully and consistently// | + | IMO, with lead chemistries((flooded, |
You will **need somewhat more Ah capacity** | You will **need somewhat more Ah capacity** | ||
* if you have undersized solar | * if you have undersized solar | ||
+ | * you have lead-chemistry battery bank | ||
You will need **somewhat less Ah capacity** | You will need **somewhat less Ah capacity** | ||
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* if you run loads in the daytime instead of at night | * if you run loads in the daytime instead of at night | ||
* if you have [[electrical: | * if you have [[electrical: | ||
+ | * you have lithium-chemistry battery bank((can be ~0.62% the size of the lead bank, due to deeper [[electrical: | ||
- | ===== alternator charging | + | ===== special case: trailers |
- | For most people living in vehicles [[electrical: | + | **Cargo trailers**((aka utility trailers)) have unique advantages and disadvantages |
- | You will need **some kind of alternator charging** | + | advantages |
- | * if you have no solar | + | * flat roof space for panels, especially cheaper-by-the-watt large panels |
- | * if you have insufficient solar <-- very common | + | * relatively low, making tiltable arrays more practical since you can reach them |
- | * if you have AGM, which craves a ton of current in Bulk charging | + | |
- | You will **not need alternator charging** | + | disadvantages |
- | * if you have [[electrical:solar: | + | * charging from alternator can be challenging. |
- | * if you stay on shore power much of the time | + | |
- | * if have solar and most of your driving happens after noon((the isolator contributes best during Bulk, which typically occurs in the morning)) | + | |
- | More expensive [[electrical: | + | **RV travel trailers** have additional challenges |
- | * you have no solar | + | * roofspace often lacks contiguous open spots to mount panels |
- | * current-hungry battery like AGM or lithium threatens your alternator' | + | * rooftop accessories [[electrical: |
- | * you have a voltage-sensitive battery like gel or lithium | + | * large parasitic [[electrical: |
- | Folks wanting to charge a trailer' | ||
===== example setups ===== | ===== example setups ===== |