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electrical:solar:sizing [2022/01/02 14:52]
frater_secessus [usable capacity in Amp-hours]
electrical:solar:sizing [2022/01/26 19:48]
princess_fluffypants [Voltage]
Line 134: Line 134:
 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:12v:electrical_notation|nominal]] [[electrical:12v:intro|12v]].  Because of this most accessories are 12v.   Most camper solar installs run at [[electrical:12v:electrical_notation|nominal]] [[electrical:12v:intro|12v]].  Because of this most accessories are 12v.  
 +
 +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.  A 24v system can use much smaller/cheaper charge controller and small/cheaper wiring to handle the same amount of power. +    * You have a //lot// of solar, like 600w or more. 
-    * the run from panels to charge controller is lengthy  +      * Ohm's law tells us that 600w / 12v = 50A but 600w / 24v = 25A.  Therefor, you can use much smaller (and cheaperwiring to connect your solar panels to the charge controllor  
-    * you will be using inverters heavily - inversion from 24vdc to 110vac is more efficient than inversion from 12vdc.+    * You will be using inverters heavily 
 +      * Inversion from 24vdc to 110vac is more efficient than inversion from 12vdc. 
 +    * You have large, power-hungry appliances that can run natively off of 24v 
 +      * Some [[food:refrigeration|DC refrigerators]] can run off of both 12v or 24v, and are slightly more efficient when running off of 24v 
 +    * You have a lot of long, large cable runs 
 +      * 24v doesn't have as much voltage drop as 12v over a similar distance, and can use smaller/cheaper cables. 
 +    * A 24v system can use a much smaller/cheaper charge controller
  
-There are downsides to 24v, however.  There are fewer 24v accessories, and you cannot use a chassis ground as it is already grounded to the coach's 12v system.+There are downsides to 24v, however.  There are fewer 24v accessories, and you cannot use a chassis ground as it is already grounded to the coach's 12v system.  It can also make alternator charging difficult, as [[https://www.amazon.com/Hyuduo-Converter-Voltage-Regulator-Stabilizer/dp/B07NM52VV5|DC-DC boost converters]] get quite expensive when they are sized to handle the required loads.
  
  
electrical/solar/sizing.txt · Last modified: 2022/01/26 19:48 by princess_fluffypants