RV and vandwellers wiki

User Tools

Site Tools

Trace:
electrical:12v:alt_and_solar

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision 		Previous revision
electrical:12v:alt_and_solar [2023/05/24 17:37]
frater_secessus [how alternator charging helps] 		electrical:12v:alt_and_solar [2024/03/31 17:05] (current)
frater_secessus [how alternator charging helps]
Line 1: Line 1:
-Note:  although this page was written with alternator-augmented solar charging in mind, the general principles also apply to solar+[[electrical:shore_power|shore power charging]] and solar+[[electrical:generator|generator]] charging. +Note:  although this page was written with alternator-augmented solar charging in mind, the general principles also apply to solar+[[electrical:shore_power|shore power charging]] and solar+[[electrical:generator|generator]] charging. Also see [[electrical:12v:power_mix|Deciding on a Power Mix]]. 
 + 
 + 
 +> Solar and DC-DC alternator charging are going to be the best practices for maintaining charge in one's battery bank. It only requires a little math, a little discipline to stick with the math, and the right expectations about solar intake.  -- CMDR_Schrodinger((https://www.reddit.com/r/vandwellers/comments/15z8eh6/energy_management_during_trips/jxfv03f/))
  
  
-[[lifestyle:words_of_wisdom|Words of wisdom]]: "Bulk charging requires //current//. Absorption requires //relatively high voltage// and //time at that voltage//." - secessus 
  
 ====== Augmented solar charging ====== ====== Augmented solar charging ======
Line 15: Line 17:
 Solar works anytime there is available sunlight, not just when the vehicle is running.  Solar works anytime there is available sunlight, not just when the vehicle is running. 
  
-Alt charging alone is unlikely to get lead-acid chemistries fully charged since Absorption can take hours and alternators often cannot hold [[electrical:solar:charge_controller_setpoints|the required voltage]]. Incomplete charge ([[electrical:12v:psoc|Partial State of Charge]], or PSOC) over time will result in [[electrical:batterycide|battery murder]] of lead batts. +Solar can meet both the **voltage** and **time** requirements necessary for [[electrical:12v:charging|complete charging]];  this is critical with lead-acid chemistries which will otherwise suffer damage from [[electrical:12v:psoc|partial states of charge]].  
  
 How to avoid (or attenuate) battery murder with this scenario: How to avoid (or attenuate) battery murder with this scenario:
   * get access to shore power every couple of days to get the bank fully charged.  This will retard the murderification process; or   * get access to shore power every couple of days to get the bank fully charged.  This will retard the murderification process; or
   * use a different (and $$$) battery alternative like LiFePO4 (no problems with PSOC) or carbon foam (needs full charge every couple of weeks?); or   * use a different (and $$$) battery alternative like LiFePO4 (no problems with PSOC) or carbon foam (needs full charge every couple of weeks?); or
-  * add in a small amount of solar.  +  * add in a small amount of solar <-- what this article is about
  
  
Line 27: Line 29:
 From ~80% to 100% (Absorption stage) charging requires little current but a long time holding at a relatively high voltage.  So in our alt+solar scenario the alternator does the heavy lifting in the beginning then a small solar install does the light (but lengthy) work at the end.((The solar will also contribute during Bulk when the sun is shining.)) From ~80% to 100% (Absorption stage) charging requires little current but a long time holding at a relatively high voltage.  So in our alt+solar scenario the alternator does the heavy lifting in the beginning then a small solar install does the light (but lengthy) work at the end.((The solar will also contribute during Bulk when the sun is shining.))
  
-Having a bit of solar may mean you can us a simpler/cheaper isolator rather than a more $$ [[electrical:12v:b2b|DC-DC charger]]. +Having a bit of solar may mean you can use a simpler/cheaper combiner rather than a more $$ [[electrical:12v:b2b|DC-DC charger]].
  
 ===== how alternator charging helps ===== ===== how alternator charging helps =====
Line 39: Line 41:
 > Use a generator or alternator to get to 85% SOC or so early in the AM, then let Solar spend all day polishing off the last 15% because that takes time more than amps. - a64pilot((https://www.cruisersforum.com/forums/f14/time-it-takes-to-fully-charge-batteries-238875-9.html#post3223983)) > Use a generator or alternator to get to 85% SOC or so early in the AM, then let Solar spend all day polishing off the last 15% because that takes time more than amps. - a64pilot((https://www.cruisersforum.com/forums/f14/time-it-takes-to-fully-charge-batteries-238875-9.html#post3223983))
  
 +
 +The alternator can help meet [[electrical:12v:charging#charging_current|lead bank minimum charging current requirements]].  
 ===== optimal alternator contribution ===== ===== optimal alternator contribution =====
  
-Broadly speaking, //alternator charging is most effective in the morning// and //solar charging is most effective later in the day//.  +Broadly speaking, //alternator charging is most effective in the morning// and //solar charging is most effective at local solar noon//.  This pattern is most evident when using isolators/relays and/or lead chemistry batteries, and less evident when using [[electrical:12v:b2b|DC-DC chargers]] and/or lithium chemistries.
  
 There are several factors in play here.   There are several factors in play here.  
Line 89: Line 93:
  
   - the Li voltage curve is very flat in the middle, so the voltage delta will be stable through the "middle 80%"   - the Li voltage curve is very flat in the middle, so the voltage delta will be stable through the "middle 80%"
-  - for average users, Li will not have an Absorption stage in the lead-chemistry sense.((advanced users may find [[electrical:12v:electrical:12v:drop-in_lifepo4#mythlithium_doesn_t_need_absorption|exceptions]] to this general statement))+  - for average users, Li will not have an Absorption stage in the lead-chemistry sense.((advanced users may find [[electrical:12v:drop-in_lifepo4#mythlithium_doesn_t_need_absorption|exceptions]] to this general statement))
   - Lithium is often charged with DC-DC, which charges at the ~same voltage as solar   - Lithium is often charged with DC-DC, which charges at the ~same voltage as solar
  
electrical/12v/alt_and_solar.1684964240.txt.gz · Last modified: 2023/05/24 17:37 by frater_secessus

Page Tools

Except where otherwise noted, content on this wiki is licensed under the following license: CC Attribution-Noncommercial-Share Alike 4.0 International

affilliate disclosure

CC Attribution-Noncommercial-Share Alike 4.0 International Donate Powered by PHP Valid HTML5 Valid CSS Driven by DokuWiki