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electrical:12v:alternator_charging_hvd [2017/10/11 14:17] frater_secessus [how to do it] |
electrical:12v:alternator_charging_hvd [2020/10/11 19:48] 127.0.0.1 external edit |
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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: | ||
===== how it works ===== | ===== how it works ===== | ||
- | [[electrical: | + | [[electrical: |
- | + | ||
- | **If this power is disconnected the isolator will turn off** and 12v systems will be separate again.((latching relays excepted)) | + | |
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- | + | ||
- | ===== disconnecting isolators and simple relays ===== | + | |
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- | ===== disconnecting voltage sensing relays ===== | + | |
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- | Example: | + | |
- | + | ||
- | On the way the alternator brings the house bank up to 13.5V. | + | |
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- | Caveat: | + | |
+ | If the device' | ||
+ | Shutting down the device will require different approaches, depending on where it gets the power to operate itself. | ||
+ | ===== solenoids and relays ===== | ||
+ | {{ https:// | ||
+ | Purely Mechanical devices like solenoids and relays use 12v //trigger// or //exciter// voltage((usually from the accessory circuit)) to operate. | ||
+ | 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)) | ||
+ | ===== voltage sensing relays ===== | ||
+ | Voltage sensing relays (VSR) typically take power from the chassis battery and have a thin ground to complete the circuit. | ||
+ | Power to VSRs is disrupted by cutting the ground wire. One way to reestablish the ground (thereby turning the device on) is HVD --> relay NO contacts --> ground wire in/out | ||
+ | ===== solid state isolators ===== | ||
+ | Some solid state isolators have a trigger or exciter input; | ||
+ | Three lug isolators without exciter input might not be usable with HVD. |