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electrical:12v:alternator_charging_hvd [2017/10/11 15:30] frater_secessus [diode based isolators] |
electrical:12v:alternator_charging_hvd [2022/07/31 00:33] (current) frater_secessus [solid state isolators] |
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====== Disconnecting alternator charging at a voltage setpoint ====== | ====== Disconnecting alternator charging at a voltage setpoint ====== | ||
- | There are scenarios where one might want to prevent | + | There are scenarios where one might want to prevent |
- | - the house battery | + | - the house battery |
+ | - the house battery might have a resting voltage high enough to trigger the house side of a dual-sensing relay (LiFePO4) | ||
- the combined circuit can feed higher-than-optimal voltages back from solar charge controller to the chassis' | - the combined circuit can feed higher-than-optimal voltages back from solar charge controller to the chassis' | ||
+ | - a [[electrical: | ||
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[[electrical: | [[electrical: | ||
- | If the device' | + | If the device' |
Shutting down the device will require different approaches, depending on where it gets the power to operate itself. | Shutting down the device will require different approaches, depending on where it gets the power to operate itself. | ||
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Power to these devices is disrupted by interrupting power to the trigger+, which is one of the small lugs.((or the only small lug in the case of 3 lug relays)) | Power to these devices is disrupted by interrupting power to the trigger+, which is one of the small lugs.((or the only small lug in the case of 3 lug relays)) | ||
- | |||
- | **Note: | ||
===== voltage sensing relays ===== | ===== voltage sensing relays ===== | ||
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===== solid state isolators ===== | ===== solid state isolators ===== | ||
- | FIXME | ||
- | Solid state isolators | + | It is unlikely you will need an HVD with a diode-based isolators because: |
+ | |||
+ | - the isolator can't backfeed voltage back to the starter battery, and | ||
+ | - voltage drops up to 1v in the diodes when passing alternator --> isolator --> house bank | ||
+ | |||
+ | But it is theoretically possible alternator voltage is so high that even with the drop you might want an HVD. Some solid state isolators | ||
+ | |||
+ | Three lug isolators without exciter input might not be usable with HVD. |