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How much power is drawn with an alarm system?

Discussion in 'Gen 3 Prius Main Forum' started by PriusII&C, Oct 18, 2021.

  1. PriusII&C

    PriusII&C Active Member

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    I bought a Kerui wireless alarm system (1 siren host, 2 motion sensors, 2 remote controllers), and intend to install it on my Gen3 Prius. The motion sensors and remote controllers have their own batteries. The siren host, however, will be powered by the Prius 12V auxiliary battery.

    But then I just realized at this moment that I forgot to consider the standby power consumed by the siren host. Without knowing the exact standby power requirement of the Kerui siren, I found something like 0.6 A for other sirens at 12V. Is this reasonable to expect?

    If the standby current is 0.6 A, then this will be a considerable load for the small auxiliary battery (or for any typical car's battery). It alone will completely drain a fully-charged brand-new Prius battery in 3 days, if the car is left turned off. So the use of a wireless alarm system is not practical.

    What is the difference between this type of system and a car's built-in alarm system? The built-in system obviously uses much less power and lasts much longer.

    Should I drop my project? Please share your knowledge and experience.
     
  2. rjparker

    rjparker Tu Humilde Sirviente

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    The siren is much different than the alarm control standby current. The siren should be in the uamps until triggered. Their spec for one system says
    Corriente en espera:< 10mA. Which model do you have?
     
    #2 rjparker, Oct 18, 2021
    Last edited: Oct 18, 2021
  3. PriusII&C

    PriusII&C Active Member

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    I cannot find the model number, but it is called "KERUI 433MHz Home Wireless Home Local Siren Speaker Burglar Alarm System kit".

    I think you are right. I contacted the seller, and he replied: "Standby current: 10mA, operating current: 700mA."

    Thanks.
     
  4. rjparker

    rjparker Tu Humilde Sirviente

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    The next step after installation and functional verification might be to verify the car's total parasitic load / standby current. It is one thing for a spec to say 10 ma which is acceptable but its another thing if it dramatically exceeds the spec. Prius v series ammeter parasitic draw setup.jpeg
    Be sure all lights are off.
     
  5. PriusII&C

    PriusII&C Active Member

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    Thanks for the good idea.