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--- electrical:solar:sizing [2021/06/21 14:11]
frater_secessus [charge controller]
+++ electrical:solar:sizing [2022/01/15 03:10]
princess_fluffypants [voltage]
@@ Line 14: / Line 14: @@
   - whether or not you have access to other forms of charging: [[electrical:shore_power|shore power]], [[electrical:12v:alternator|alternator]], [[electrical:generator|generator]]
   - the kind of [[electrical:12v:deep_cycle_battery|battery chemistry]] - some((lithium, for example)) charge more efficiently than others
-  - These factors will tell you size of the system needed.  If the system you need will not physically fit on/in your vehicle, you will have to take [[electrical:solar:sizing#maxxed_system|a different approach]].
+  - the kind of camping you do.  Full-timers will need more robust systems.  Weekenders can [[https://mouse.mousetrap.net/blog/2020/07/04/agm-for-weekenders/|"get by" then recharge batteries fully at home]].
+These factors will dictate the system capactity you will need.  If the system you need will not physically fit on/in your vehicle, you will have to take [[electrical:solar:sizing#maxxed_system|a different approach]].
@@ Line 99: / Line 101: @@
 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.  Charging at lesser rates may result in not getting fully charged each day.  Charging at greater rates may result in increased outgassing and the need for a lengthier Absorption stage.
+=== reserve ===
+|  **total**|  91|
+| | |
+|  Minimum battery bank((except lithium))|  182|
+and that's just to get through a 24hr period **with good sun**.  If you want to get through a day (or more) of terrible solar yield (rain, snow, fog) it requires even more battery capacity (//reserve//), money, and cargo capacity. These numbers are both very rough but will illustrate the pattern:
+| |  **Rated Ah**|  **cost (flooded)**|  **cost (AGM)**|  **weight in lbs**|
+|  **Minimum battery bank((except lithium))
+days of reserve**|  182|  $182.00|  $364.00|  91|
+| | | | | |
+|  **1 day of reserve**|  364|  $364.00|  $728.00|  182|
+|  **2 days of reserve**|  546|  $546.00|  $1,092.00|  273|
+|  **3 days of reserve**|  728|  $728.00|  $1,456.00|  364|
 ==== charging efficiency ====
@@ Line 107: / Line 134: @@
 Lithium batteries have very high charging efficiency, so 50A consumed will take ~50A to recharge.
-==== voltage ====
+==== Voltage ====
 Most camper solar installs run at [[electrical:12v:electrical_notation|nominal]] [[electrical:12v:intro|12v]].  Because of this most accessories are 12v.

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