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electrical:12v:alternator [2020/07/04 14:05]
frater_secessus [effect on GDI engines] |
electrical:12v:alternator [2020/10/08 16:53]
frater_secessus [gotchas] |
| Alternator charging is generally only practical for the [[electrical:12v:charging|bulk charge stage]] due to relatively low voltage output and the [[electrical:12v:charging|long time periods required for absorption]].(([[electrical:12v:b2b|DC-DC chargers]] can help with the voltage)) It is unlikely to get the house battery completely charged unless one is driving significant distances. This can have an impact on [[electrical:batterycide|battery longevity]]. If one drives often [[electrical:12v:alt_and_solar|a combination of the alternator doing bulk charging and a small solar doing the rest]] is good match. | Alternator charging is generally only practical for the [[electrical:12v:charging|bulk charge stage]] due to relatively low voltage output and the [[electrical:12v:charging|long time periods required for absorption]].(([[electrical:12v:b2b|DC-DC chargers]] can help with the voltage)) It is unlikely to get the house battery completely charged unless one is driving significant distances. This can have an impact on [[electrical:batterycide|battery longevity]]. If one drives often [[electrical:12v:alt_and_solar|a combination of the alternator doing bulk charging and a small solar doing the rest]] is good match. |
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| Vehicles with //smart// (variable voltage) alternators may not be suitable for charging with normal isolators.((https://www.redarc.com.au/how-do-i-know-if-i-have-a-variable-voltage-smart-alternator)) See [[electrical:12v:b2b|DC-DC chargers]]. | Vehicles with //smart// (variable voltage) alternators may not be suitable for charging with normal isolators.((https://www.redarc.com.au/how-do-i-know-if-i-have-a-variable-voltage-smart-alternator)) See [[electrical:12v:alternator#smart_alternators|below]]. |
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| See [[electrical:12v:mandatory solar|Is Solar Mandatory?]] for ideas on how to charge primarily by alternator. | See [[electrical:12v:mandatory solar|Is Solar Mandatory?]] for ideas on how to charge primarily by alternator. |
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| Alternator charging may bring some battery chemistries (like lithium) to **unsuitably high voltages**. A [[electrical:12v:hvd|high voltage disconnect]] can [[electrical:12v:alternator charging hvd|restrict alternator charging to lower voltages]]. [[electrical:12v:b2b|DC-DC chargers]] can also regulate voltage provided to the house battery. | Alternator charging may bring some battery chemistries (like lithium) to **unsuitably high voltages**. A [[electrical:12v:hvd|high voltage disconnect]] can [[electrical:12v:alternator charging hvd|restrict alternator charging to lower voltages]]. [[electrical:12v:b2b|DC-DC chargers]] can also regulate voltage provided to the house battery. |
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| | Solar charging while the isolator circuit is closed (ie, batteries connected) can pass higher-than-normal voltage to the chassis and starter battery. See notes on HVD and DC-DC charging above. |
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| | Voltage-sensing regulators can be [[http://bdp.mousetrap.net/index.php/2018/10/27/side-effect-of-solar-alternator-charging/|triggered or "held closed" by voltage from the solar-charged side]] in some scenarios. Address with HVD as above if desired. |
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| **Idling the engine** to charge house batteries **can seriously overheat the alternator**. It is usually cooled by wind from the vehicle's forward motion; a fan may help cool the alternator. | **Idling the engine** to charge house batteries **can seriously overheat the alternator**. It is usually cooled by wind from the vehicle's forward motion; a fan may help cool the alternator. |
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| In early morning when house battery voltage is lowest, **a plain solenoid may unintentionally allow depleted batteries to pull down the starter battery**. Workarounds: use a VSR, or start the vehicle immediately after inserting the key((ie, do not leave in the Accessory position which would drain the starter battery)). | In early morning when house battery voltage is lowest, **a plain solenoid may unintentionally allow depleted batteries to pull down the starter battery**. Workarounds: use a VSR, or start the vehicle immediately after inserting the key((ie, do not leave in the Accessory position which would drain the starter battery)). |
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| | Solar charging while the isolator circuit is closed may [[opinion:frater_secessus:alternatorSolarStall|"stall" at alternator voltage]]. |
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| ===== wiring ===== | ===== wiring ===== |
