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electrical:12v:alternator [2019/10/17 13:54]
frater_secessus [limitations] |
electrical:12v:alternator [2020/01/21 21:26]
frater_secessus [isolators] |
| Power from the alternator is shared with the house battery using an isolator of some sort. This allows the [[electrical:12v:intro|house battery]] to charge but does not allow the house battery to pull power from the starter battery. | Power from the alternator is shared with the house battery using an isolator of some sort. This allows the [[electrical:12v:intro|house battery]] to charge but does not allow the house battery to pull power from the starter battery. |
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| - [[http://amzn.to/2fZCfEr|constant-duty solenoid]] switch - an electromechanical device which uses an electromagnet to complete the charging circuit when the engine is running. **Solenoids are generally cylindrical**. Energizing the solenoid will cause a **0.5A - 1A current drop** between the alternator and house battery.((http://www.cheaprvliving.com/forums/Thread-Questions-about-continuous-duty-solenoid?pid=229761#pid229761)). SternWake recommends the [[http://amzn.to/2fZLFzs|Blue Sea 9012]].((http://www.cheaprvliving.com/forums/Thread-Questions-about-continuous-duty-solenoid?pid=229761#pid229761)) \\ Solenoids can be used for [[electrical:12v:self-jumpstarting|self-jumpstarting]] //if// the chassis battery has enough juice to engage the solenoid. | ==== constant-duty solenoid ==== |
| - [[http://amzn.to/2gVmLFU|{{ https://images-na.ssl-images-amazon.com/images/I/418qcncjT0L._AC_US218_.jpg|}}]]voltage sensing relays - this kind of isolator is **installed between the house and starter batteries**. It does not get trigger voltage from the fuse panel but rather reads the voltages of one or both batteries to know when to switch on. \\ This kind of isolator may have a "combine" override function to enable self-jumpstarting. | |
| | A [[http://amzn.to/2fZCfEr|constant-duty solenoid]] is an electromechanical device which uses an electromagnet to complete the charging circuit when the engine is running. **Solenoids are generally cylindrical**. Energizing the solenoid will cause a **0.5A - 1A current drop** between the alternator and house battery.((http://www.cheaprvliving.com/forums/Thread-Questions-about-continuous-duty-solenoid?pid=229761#pid229761)). SternWake recommends the [[http://amzn.to/2fZLFzs|Blue Sea 9012]].((http://www.cheaprvliving.com/forums/Thread-Questions-about-continuous-duty-solenoid?pid=229761#pid229761)) \\ Solenoids can be used for [[electrical:12v:self-jumpstarting|self-jumpstarting]] //if// the chassis battery has enough juice to engage the solenoid. |
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| | ==== voltage-sensing relays ==== |
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| | [[http://amzn.to/2gVmLFU|{{ https://images-na.ssl-images-amazon.com/images/I/418qcncjT0L._AC_US218_.jpg|}}]]voltage sensing relays - this kind of isolator is **installed between the house and starter batteries**. It does not get trigger voltage from the fuse panel but rather reads the voltages of one or both batteries to know when to switch on. \\ This kind of isolator may have a "combine" override function to enable self-jumpstarting. |
| - [[http://amzn.to/2h2tDxp|single voltage sensing]] - this type reads the voltage of only one battery. In the case of an RV it would read the voltage of the starting battery. When it is high enough (ie, charged or being charged by alternator) it connects the starting and house batteries. Example: [[http://amzn.to/2h2tDxp|Sure Power 1314]]. [secessus says: "IMO the practical benefit (if any) to charging the starter battery "first" is keeping the load on the alternator reasonable."] | - [[http://amzn.to/2h2tDxp|single voltage sensing]] - this type reads the voltage of only one battery. In the case of an RV it would read the voltage of the starting battery. When it is high enough (ie, charged or being charged by alternator) it connects the starting and house batteries. Example: [[http://amzn.to/2h2tDxp|Sure Power 1314]]. [secessus says: "IMO the practical benefit (if any) to charging the starter battery "first" is keeping the load on the alternator reasonable."] |
| - [[http://amzn.to/2gVmLFU|dual voltage sensing]] - this type reads the voltage from both batteries and when either is high enough it connects the batteries. This may or may not be what an RVer wants, as it could consume some solar power to to engergize the solenoid and charge the starter battery. It would also backfeed excessive [[electrical:12v:charging|equalization]] voltages to the coach system. Example: [[http://amzn.to/2gVmLFU|Sure Power 1315]] | - [[http://amzn.to/2gVmLFU|dual voltage sensing]] - this type reads the voltage from both batteries and when either is high enough it connects the batteries. This may or may not be what an RVer wants, as it could consume some solar power to to engergize the solenoid and charge the starter battery. It would also backfeed excessive [[electrical:12v:charging|equalization]] voltages to the coach system. Battery chemistries with higher resting voltages like LiFePO4((or 4S non-LFP lipo)) could also trigger the isolator. Examples: [[http://amzn.to/2gVmLFU|Sure Power 1315]], [[https://amzn.to/37gcdIv|BlueSea SI-ACR]] |
| - DC-DC isolators (aka //[[electrical:12v:b2b|b2b]] isolators//) that boost charging voltage to [[electrical:12v:charging|Absorption]] voltages | - DC-DC isolators (aka //[[electrical:12v:b2b|b2b]] isolators//) that boost charging voltage to [[electrical:12v:charging|Absorption]] voltages |
| - [[http://amzn.to/2gVwmKw|solid state isolator]] - an electronic device which uses diodes to prevent depletion of the starter battery. **Isolators are generally brick-shaped**. Diode-based isolators have a **0.5v - 1v drop** between the alternator and house battery. This may be desirable if the house battery is a lower-voltage chemistry like [[electrical:12v:lifepo4_batteries_thread|LiFePO4]]. Some solid state isolaters use FETs and diodes in tandem to reduce voltage drop. \\ Note: solid state relays can't combine batteries for self-jumpstarting. | |
| - manual switch - A [[http://amzn.to/2gsDtNc|manual battery switch]] normally has 4 positions: A, B, A+B, and Off. A would be for the starter battery and used during starting. B would be used for house use when one is not driving. A+B could be used to combine both sets for starting or for charging while driving. This kind of setup is prone to user error. A manual switch has no current or voltage losses. | ==== diode-based isolator ==== |
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| | [[http://amzn.to/2gVwmKw|Solid state isolators]] are an electronic devices which use diodes to prevent depletion of the starter battery. **Isolators are generally brick-shaped**. Diode-based isolators have a **0.5v - 1v drop** between the alternator and house battery. This may be desirable if the house battery is a lower-voltage chemistry like [[electrical:12v:lifepo4_batteries_thread|LiFePO4]]. Some solid state isolaters use FETs and diodes in tandem to reduce voltage drop. \\ Note: solid state relays can't combine batteries for self-jumpstarting. |
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| | ==== manual switch ==== |
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| | A [[http://amzn.to/2gsDtNc|manual battery switch]] normally has 4 positions: A, B, A+B, and Off. A would be for the starter battery and used during starting. B would be used for house use when one is not driving. A+B could be used to combine both sets for starting or for charging while driving. This kind of setup is prone to user error. A manual switch has no current or voltage losses. |
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| ===== sizing an isolator ===== | ===== sizing an isolator ===== |
