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electrical:solar:sizing [2021/06/21 14:15] frater_secessus [Sizing a solar installation] |
electrical:solar:sizing [2022/01/26 19:48] princess_fluffypants [Voltage] |
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A rule of thumb is flooded lead acid batteries in offgrid scenarios should be charged between C/10 and C/8. For a 200AH bank this would be 20A-25A. | A rule of thumb is flooded lead acid batteries in offgrid scenarios should be charged between C/10 and C/8. For a 200AH bank this would be 20A-25A. | ||
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+ | === reserve === | ||
+ | |||
+ | |||
+ | |||
+ | |||
+ | |||
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+ | | **total**| | ||
+ | | | | | ||
+ | | Minimum battery bank((except lithium))| | ||
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+ | and that's just to get through a 24hr period **with good sun**. | ||
+ | |||
+ | | | **Rated Ah**| **cost (flooded)**| | ||
+ | | **Minimum battery bank((except lithium)) | ||
+ | 0 days of reserve**| | ||
+ | | | | | | | | ||
+ | | **1 day of reserve**| | ||
+ | | **2 days of reserve**| | ||
+ | | **3 days of reserve**| | ||
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+ | |||
==== charging efficiency ==== | ==== charging efficiency ==== | ||
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Lithium batteries have very high charging efficiency, so 50A consumed will take ~50A to recharge. | Lithium batteries have very high charging efficiency, so 50A consumed will take ~50A to recharge. | ||
- | ==== voltage | + | ==== Voltage |
Most camper solar installs run at [[electrical: | Most camper solar installs run at [[electrical: | ||
+ | |||
+ | Some installations utilize 24v electrical systems. This is common in boats, and occasionally some very large commercial RVs. The common theme of an advantage to 24v is that you're using half the amperage to transfer the same amount of power, which can result in cheaper components | ||
You may want to consider running a 24v system if: | You may want to consider running a 24v system if: | ||
- | * your panels are rated at 600w or higher - Ohm's law tells us that 600w / 12v = 50A but 600w / 24v = 25A. | + | * You have a //lot// of solar, like 600w or more. |
- | * the run from panels to charge | + | * Ohm's law tells us that 600w / 12v = 50A but 600w / 24v = 25A. |
- | * you will be using inverters heavily | + | * You will be using inverters heavily |
+ | * Inversion | ||
+ | * You have large, power-hungry appliances that can run natively off of 24v | ||
+ | * Some [[food: | ||
+ | * You have a lot of long, large cable runs | ||
+ | * 24v doesn' | ||
+ | * A 24v system can use a much smaller/ | ||
- | There are downsides to 24v, however. | + | There are downsides to 24v, however. |