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lifestyle:faq_solar_generator [2023/05/17 09:33] frater_secessus [Solar generators] |
lifestyle:faq_solar_generator [2024/02/05 18:50] (current) princess_fluffypants |
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+ | ====== Solar generators ====== | ||
Words of wisdom: | Words of wisdom: | ||
+ | ===== TL;DR ===== | ||
+ | |||
+ | |||
+ | **These things are // | ||
- | ====== Solar generators ====== | ||
[[https:// | [[https:// | ||
- | "Solar Generators" | + | "Solar Generators" |
- | * A battery | + | * A [[electrical: |
* USB outlet[s] and 12v outlet[s] | * USB outlet[s] and 12v outlet[s] | ||
* An [[electrical: | * An [[electrical: | ||
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These devices are packaged for convenience and are usually much more expensive than the components bought separately. | These devices are packaged for convenience and are usually much more expensive than the components bought separately. | ||
- | Less expensive "solar generators" | + | Less expensive "solar generators" |
The overall proposition can be summed up by the title of a Bob Wells video, [[https:// | The overall proposition can be summed up by the title of a Bob Wells video, [[https:// | ||
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Specs for these devices are often given in nonstandard or even misleading ways. The following discussion will use the Yeti shown above, although their product description is better than most. | Specs for these devices are often given in nonstandard or even misleading ways. The following discussion will use the Yeti shown above, although their product description is better than most. | ||
+ | |||
+ | ==== TLDR ==== | ||
+ | |||
+ | We are most interested in | ||
+ | |||
+ | * how much capacity the bank has (typically in Watt-hours, Wh) | ||
+ | * charging limits | ||
+ | * by car adapter (typically ≤120w because of limitations of the ciggy port) | ||
+ | * by wall adapter (volts and amps, sometimes the stock wall charger makes lower power than is otherwise possible) | ||
+ | * by solar ([[electrical: | ||
+ | * DC output (typically 10A at 12v) | ||
+ | * AC output (given as Watts, the biggest AC loads you can run) | ||
==== capacity ==== | ==== capacity ==== | ||
- | |||
- | Ah are often expressed as mAh. Which is more impressive, 33Ah or 33, | + | Capacity is most often listed in Wh (watt-hours), |
+ | Nefarious marketers sometimes multiply each cell's Ah rating times the number of cells, resulting in a 3x inflation of Ah rating. | ||
- | The 33Ah **capacity** lead-acid battery in the example above is stated as 400Wh. | ||
- | Nefarious marketers sometimes multiply each cell's Ah rating times the number of cells, resulting in a 3x inflation of Ah rating. | + | === usable capacity === |
- | On the upside, they have almost no peukert effect and therefore can support heavier loads (at the expense of running time). | + | |
+ | Most people know that only about 50% of lead batt capacity should be used in order to ensure a long life. Lithium also has a recommended safety margin, 20%. This means 80% of the rated capacity can be used and still hit the manufacturer' | ||
+ | |||
+ | With 320Wh usable we could run the a theoretical 400w inverter at max load for 48minutes. | ||
- | You could run run [[electrical: | ||
==== cell chemistry ==== | ==== cell chemistry ==== | ||
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Inverters are typically rated on their // | Inverters are typically rated on their // | ||
- | ==== solar charging limits | + | ==== solar input ==== |
+ | |||
+ | If the [[electrical: | ||
+ | |||
+ | === solar charging limits === | ||
Many smaller units have quite restrictive solar input limits. | Many smaller units have quite restrictive solar input limits. | ||
* **voltage** - 22Voc is a common voltage limit, effectively limiting one to [[electrical: | * **voltage** - 22Voc is a common voltage limit, effectively limiting one to [[electrical: | ||
- | * **current** limit - 3A is a common input current limit on smaller, less-expensive units. | + | * **current** limit - 3A is a common input current limit on smaller, less-expensive units. |
+ | * With PWM controllers the max power harvestable will be 3A x [internal battery voltage], which can be as low as 9v. 9v x 3A 27w. | ||
+ | * MPPT controllers with the same limit might run the panels at 18v, the Vmp: 18v x 3A = 54w((minus DC-DC conversion losses of ~5%)) | ||
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12v ciggy port -> SG | 12v ciggy port -> SG | ||
- | + | | |
- | | + | |
The situation with solar would be even worse, because it might take all day to charge from solar and the SG could not power other devices for that day. | The situation with solar would be even worse, because it might take all day to charge from solar and the SG could not power other devices for that day. | ||
==== regulated DC output ==== | ==== regulated DC output ==== |