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electrical:solar [2017/05/29 09:36] frater_secessus [amp-hours needed] |
electrical:solar [2022/01/28 19:12] princess_fluffypants |
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====== Solar power ====== | ====== Solar power ====== | ||
- | Solar (photovoltaic or PV) power is an excellent fit for ' | + | [Note: |
+ | |||
+ | Solar (photovoltaic or PV) power is an excellent fit for ' | ||
Broadly speaking, **solar power systems consist of** [[electrical: | Broadly speaking, **solar power systems consist of** [[electrical: | ||
- | Under normal use solar setups charge during the daytime and discharge at night; the lowest [[electrical: | + | Under normal use solar setups charge |
+ | |||
+ | The most difficult part of a solar power system (other than [[electrical: | ||
+ | |||
+ | |||
+ | ===== Do you need solar? ===== | ||
+ | |||
+ | Maybe not. If any of these conditions are met you probably don't need solar: | ||
+ | |||
+ | * you stay in campgrounds or other places with access to [[electrical: | ||
+ | * you have a [[electrical: | ||
+ | |||
+ | |||
+ | |||
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+ | ===== Practical considerations ===== | ||
+ | |||
+ | * [[electrical: | ||
+ | * panels are coming down in price but are $$$ to ship. Where will you get them? | ||
+ | * wiring from the panels will have to enter the camper body somewhere, and the entry will have to be waterproof | ||
+ | * lead acid batteries (flooded, sealed, AGM, etc) are extremely heavy and bulky. | ||
+ | * wiring from power sources will need to be fused or fitted with circuit breakers | ||
+ | * how will you ensure your batteries don't run your batteries too low and damage them? | ||
+ | |||
+ | ===== Scheduling your use of solar power ===== | ||
+ | |||
+ | //When// you use power from your system can be as important as //how much// power you use. | ||
+ | |||
+ | There are times (bulk, early absorption) when the system is struggling to charge the lead-chemistry bank; loads should be minimized during these periods. | ||
+ | |||
+ | At other times like late absorption and float the system will have [[electrical: | ||
+ | |||
+ | |||
- | The most difficult part of a solar power system (other than paying for it!) is [[electrical: | + | ===== Things |
- | ===== things | + | |
* Insolation (Intensity of sunlight) | * Insolation (Intensity of sunlight) | ||
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- | ===== sizing a solar installation | + | ===== How much solar? ===== |
+ | |||
+ | Solar sizing has been moved to [[electrical: | ||
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- | ===== weather-related issues ===== | + | ===== Weather-related issues ===== |
- | ==== cloudy | + | Weather and [[electrical: |
+ | ==== Cloudy | ||
**Cloud cover** can have paradoxical effects: | **Cloud cover** can have paradoxical effects: | ||
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* when the **sun is near the edge of a cloud** you can get spikes in current, called Edge of Cloud Effect (ECE). | * when the **sun is near the edge of a cloud** you can get spikes in current, called Edge of Cloud Effect (ECE). | ||
- | Rainy weather causes a drop in current due to the cloud cover effect. | + | Rainy weather causes a drop in current due to the cloud cover effect. An upside is it can wash dust off panels. |
Dusty or snowy weather can cause a loss of output due to physical presence on the panels. | Dusty or snowy weather can cause a loss of output due to physical presence on the panels. | ||
- | ==== temperature | + | ==== Temperature |
Panels yield the most power in cold temperatures. | Panels yield the most power in cold temperatures. | ||
+ | ===== Mounting the panels ===== | ||
+ | |||
+ | [based on [[https:// | ||
+ | |||
+ | |||
+ | There are a few issues to consider: | ||
+ | |||
+ | * solar cells get very hot in sunlight, typically 25deg C hotter than ambient temps. Rating lab tests are performed when the cells are 25deg C (0deg C ambient, freezing) | ||
+ | * [[electrical: | ||
+ | hot panels re-radiate heat onto the roof of the van. "On my white van (even with a 5" airgap) it is hotter in the | ||
+ | shade under the panels than on the roof in direct sunlight." | ||
+ | * we prefer fewer holes in the van roof when possible | ||
+ | * " | ||
+ | * airgapped panels will add height for drive-through adventures | ||
+ | * taller racks will likely increase air drag and MPG, particularly if you drive fast | ||
+ | |||
+ | **Mounting hard panels to a rack** increases airflow (thereby reducing heat-related power losses), reduces heat transfer, and minimizes the number of holes in the van roof. | ||
+ | |||
+ | **Mounting hard panels directly to the roof** still allows some airgap (the depth of the frame) and the roof corrugations will allow some airflow in the direction of the " | ||
+ | |||
+ | **Mounting flex panels to the roof** allows some airflow in the corrugations but no airgap. Good news: panel derating won't be so bad because the heat is conducted to your van roof. Which is bad news if it's already hot in your van. | ||
+ | Opinion: |