RV and vandwellers wiki

User Tools

Site Tools

Trace:
electrical:12v:alternator

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:alternator [2024/04/09 14:41]
frater_secessus [limitations] timing 		electrical:12v:alternator [2024/04/26 17:11] (current)
frater_secessus [sizing the wire]
Line 15: Line 15:
   * In many situations, it is possible to use a simple/inexpensive battery [[electrical:12v:alternator#combiners|combiner]] or [[electrical:12v:alternator#proper_isolators|isolator]] between the house batteries and the vehicle battery. These will allow the house battery to charge when the vehicle is running, but will prevent the vehicle battery from being drained when the engine is off.   * In many situations, it is possible to use a simple/inexpensive battery [[electrical:12v:alternator#combiners|combiner]] or [[electrical:12v:alternator#proper_isolators|isolator]] between the house batteries and the vehicle battery. These will allow the house battery to charge when the vehicle is running, but will prevent the vehicle battery from being drained when the engine is off.
     * Some situations may benefit from or [[electrical:12v:mandatory_dcdc|require DC-DC chargers]] in between the vehicle batteries and the house batteries.      * Some situations may benefit from or [[electrical:12v:mandatory_dcdc|require DC-DC chargers]] in between the vehicle batteries and the house batteries. 
 +  * charging is //triggered// by a 12v signal(("D+", "IGN", "ACC")) and/or by voltage-sensing((monitoring of the actual voltage coming from the chassis)) 
   * Idling the engine while parked for long periods of time just to recharge the batteries is possible, but generally a bad idea.   * Idling the engine while parked for long periods of time just to recharge the batteries is possible, but generally a bad idea.
     * Pulling a lot of power from the alternator causes it to generate a lot of heat. When the vehicle is moving there's enough airflow to keep the alternator cool, but when parked the heat will build up and can damage the alternator.     * Pulling a lot of power from the alternator causes it to generate a lot of heat. When the vehicle is moving there's enough airflow to keep the alternator cool, but when parked the heat will build up and can damage the alternator.
Line 112: Line 113:
  
 See [[electrical:12v:alternator_details#heat|this sub-article]] on alternators and heat See [[electrical:12v:alternator_details#heat|this sub-article]] on alternators and heat
-==== charging current patterns ====+ 
 + 
 +==== alternator current rating ==== 
 + 
 +In general, vehicles with higher-rated alternators (150A, for example) will handle a given load better than vehicles with lower-rated alternators (60A, for example).  The rating in Amps will be listed on the window sticker, often on the alternator housing itself, or can be looked up using a VIN decoder for your automaker.   
 + 
 +see [[electrical:12v:alternator_details#current|this related article]] on assessing how much current you can safely take from the alternator 
 + 
 + 
 +==== fuel consumption ==== 
 + 
 +Fuel consumption for power generation will be greatest when the vehicle is idled.  When charging loads are imposed on a vehicle that is already driving the added cost can be minimal. 
 + 
 +Using the 3.6L [[rv:ram_promaster|Promaster]] with a 40A [[electrical:12v:b2b|DC-DC charger]] as an example, ObvB estimates: 
 + 
 +>> In terms of cost, an average USA price of gas at $3.36, **idling** for 2 hours to produce 1kWh with a 40A DC-DC charger would burn 2 * (2/3 + 0.074) gal = 1.48 gal = **$4.97 / kWh**. If you were going to be **driving** anyway, then the additional cost of turning on a DC-DC charger (using my assumptions) would be about **50c/kWh**.((https://www.promasterforum.com/threads/fuel-consumption-at-idle.103939/post-841876))  
 + 
 + 
 + 
 +===== charging current patterns =====
  
   * charging lead chemistries directly from the alternator tends toward    * charging lead chemistries directly from the alternator tends toward 
Line 132: Line 152:
  
 ''23A x 20 minutes / 60 minutes in an hour = 7.666666667Ah'' ''23A x 20 minutes / 60 minutes in an hour = 7.666666667Ah''
- 
- 
-==== alternator current rating ==== 
- 
-In general, vehicles with higher-rated alternators (150A, for example) will handle a given load better than vehicles with lower-rated alternators (60A, for example).  The rating in Amps will be listed on the window sticker, often on the alternator housing itself, or can be looked up using a VIN decoder for your automaker.   
- 
-see [[electrical:12v:alternator_details#current|this related article]] on assessing how much current you can safely take from the alternator 
- 
-===== fuel consumption ===== 
- 
-Fuel consumption for power generation will be greatest when the vehicle is idled.  When charging loads are imposed on a vehicle that is already driving the added cost can be minimal. 
- 
-Using the 3.6L [[rv:ram_promaster|Promaster]] with a 40A [[electrical:12v:b2b|DC-DC charger]] as an example, ObvB estimates: 
- 
->> In terms of cost, an average USA price of gas at $3.36, **idling** for 2 hours to produce 1kWh with a 40A DC-DC charger would burn 2 * (2/3 + 0.074) gal = 1.48 gal = **$4.97 / kWh**. If you were going to be **driving** anyway, then the additional cost of turning on a DC-DC charger (using my assumptions) would be about **50c/kWh**.((https://www.promasterforum.com/threads/fuel-consumption-at-idle.103939/post-841876))  
  
  
Line 569: Line 574:
 It may be desirable to disable alternator charging on-the-fly when stopped in traffic, on hot days, to avoid charging frozen Li cells,((using a temperature controller)) stop charging at a given voltage,((using a [[electrical:12v:alternator_charging_hvd|High Voltage Disconnect]])) or neutralize [[electrical:12v:alternator#gotchas|gotchas]], etc.  The method of disabling will vary depending on the gear: It may be desirable to disable alternator charging on-the-fly when stopped in traffic, on hot days, to avoid charging frozen Li cells,((using a temperature controller)) stop charging at a given voltage,((using a [[electrical:12v:alternator_charging_hvd|High Voltage Disconnect]])) or neutralize [[electrical:12v:alternator#gotchas|gotchas]], etc.  The method of disabling will vary depending on the gear:
  
-  * relays and DC-DC that are triggered solely by D+ can be disabled by a switch on the D+ wire+  * relays and DC-DC that are triggered solely by D+ can be disabled by a switch on the D+ wire.  [[https://www.reddit.com/r/VanLife/comments/1c4vjl0/is_this_renogy_a_good_dcdc_option_for_a_200ah/kzuc78v/|Additional control could be introduced]] with a relay and or delay ([[https://amzn.to/3TUEbmu|example]])
   * VSR triggered by voltage can can be disabled by a switch on the thin ground wire on the VSR itself.((the VSR requires a ground to make a complete circuit to run internal electronics.  Breaking this circuit turns off the  VSR))     * VSR triggered by voltage can can be disabled by a switch on the thin ground wire on the VSR itself.((the VSR requires a ground to make a complete circuit to run internal electronics.  Breaking this circuit turns off the  VSR))  
   * some DC-DC can be //derated// by providing a 12v signal to the CURRENT LIMIT terminal ([[electrical:12v:b2b#renogy1|Renogy DC1212 series]], [[electrical:12v:b2b#leaptrend|Leaptrend]])   * some DC-DC can be //derated// by providing a 12v signal to the CURRENT LIMIT terminal ([[electrical:12v:b2b#renogy1|Renogy DC1212 series]], [[electrical:12v:b2b#leaptrend|Leaptrend]])
Line 651: Line 656:
   - use [[electrical:12v:b2b|a DC-DC charger]] to get at least the correct charging voltage   - use [[electrical:12v:b2b|a DC-DC charger]] to get at least the correct charging voltage
   - if charging by relay only, use Crtical size wire to get the most voltage and current to the lead house battery   - if charging by relay only, use Crtical size wire to get the most voltage and current to the lead house battery
 +
 +==== triggering  ====
 +
 +The setup needs to be //triggered// (told when to start/stop) so that it isn't connected all the time.  There are two main methods:
 +
 +  - use of an ON/OFF 12v trigger signal ("D+", "IGN", "ACC").  When the 12v signal is present the charging circuit is operational.  Caveat:  in this kind of setup leaving the key in the ACC position without starting the engine can drain the starter battery. 
 +  - voltage-sensing - 12v is always being provided to the charger.  The batteries are connected when the chassis voltage is above a voltage setpoint (often ≥13.4v) and disconnected when the chassis side measures below  a setpoing (often ≤13.2v).  
 +
 +In some cases both are combined for particular installs.  Ex.  smart alternators. 
 +
 +
 +
  
 ===== alternator hacks ===== ===== alternator hacks =====
electrical/12v/alternator.1712688101.txt.gz · Last modified: 2024/04/09 14:41 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