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Can cigarette lighter outlet handle 7 to 8 amps draw ?

Discussion in 'Prime Main Forum (2017-2022)' started by GKL, Jan 20, 2023.

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  1. GKL

    GKL Active Member

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    We have a 2020 Prius Prime XLE and I need to know if I can plug into the cigarette outlet a mobile ham radio that is rated to draw 7 to 8 amps ?

    (the working voltage is from DC12V-DC13.8V)

    (the radio has a max power of 25 watts)

    We would not want to modify the car to runs wires directly to the battery.

    Thanks in advance for any replies !

    Gary
     
  2. Salamander_King

    Salamander_King Senior Member

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    It is rated at 12v/120w. So it is rated at 10A max. As long as it does not exceed that, it should be fine.

    upload_2023-1-20_21-36-49.png
     
    #2 Salamander_King, Jan 20, 2023
    Last edited: Jan 20, 2023
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  3. GKL

    GKL Active Member

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    Thanks ! appreciate the info, just wanted to be sure when messing with the electrical system :D
     
  4. Gokhan

    Gokhan Senior Member

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    On my 1985 Corolla LE, the fuse for the cigarette lighter and digital clock was 15 A. It is probably still the same. So, even 12 A is probably OK. Back then, the regulated voltage with the alternator running was 14.3 V. It is probably close to 12 V now.
     
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  5. GKL

    GKL Active Member

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    Thanks for sharing that, after having searched and read posts about electrical fires related to the cigarette lighter outlet I just wanted to be extra sure :D

    As far as the voltage it would not be a problem if it did go a little over 12v as the radio I am considering buying says it has a voltage range of DC12V-DC13.8V.
     
  6. Salamander_King

    Salamander_King Senior Member

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    I think that is the range of the voltage supplied by the 12v battery in the car which is acceptable by your device. The voltage fluctuates as you draw more or the DC-DC charger kicks in while in READY mode. It just is saying that your device is OK to use with fluctuating voltage. Just make sure that you have your car in READY mode (does not have to have the engine running). If you keep it in ACC or ON mode, the 12v battery will deplete very quickly.
     
    #6 Salamander_King, Jan 21, 2023
    Last edited: Jan 21, 2023
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    So watts is volts times amps? I think someone tried to teach me that, about 56 years ago... :unsure:
     
  8. GKL

    GKL Active Member

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    Thanks for the warning about ACC mode ! The ham radio ad actually seems to state that the preferred voltage for full power is 13.8 but will still function okay with at least 12 volts.
     
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  9. GKL

    GKL Active Member

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    Wow, 56 years ago ? I remember learning it roughly about 53 years ago as a 17 year old going to a Navy advanced electronics school, kinda wished I'd stayed in electronics when I got out, but I have remembered a fair bit of the basics :D

    ......still wanted extra assurance about the Prime outlet just to be sure ! :D
     
  10. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah for me it was in Junior High vocational class. Something like 56 years anyway.
     
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  11. GKL

    GKL Active Member

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    Neat, amazing how much stuff like that we can remember from way back when ! :D
     
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  12. Salamander_King

    Salamander_King Senior Member

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    Yeah, not that I was ever good at Physics, but at least I could recall my rudimentary knowledge of Ohm's law.

    upload_2023-1-21_12-59-20.png
     
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  13. ChapmanF

    ChapmanF Senior Member

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    At least in Gen 3 Prius, the voltage (while the system is READY) can be changed by the ECU based on various electrical needs, whether the car is moving or stopped, and what the ECU thinks about the charge state of the 12 volt battery. It can sometimes be as high as 14.8 and doesn't often go lower than 13.5, though it can if lots of power-hungry things are running. I don't think anyone has completely figured out the ECU's rules for what voltage it selects when. There are some threads (look. maybe, for member RGeB) showing plots of how the voltage jumps around over the course of a drive.

    Then, when the car isn't READY, say it's in ON or ACC, the voltage is likely to be below 12.8 and sometimes below 12 if you're pushing it.

    Normally, devices that are made for an automotive "12 volt" system are robustly built for that wide a range of voltage, which isn't that different from what was seen in old cars with alternators and basic vibrating-reed regulators. So the radio will probably be just fine. Not sure why they'd publish 13.8 as its top limit though. It's not so unusual for cars to go above that.
     
    #13 ChapmanF, Jan 21, 2023
    Last edited: Jan 21, 2023
  14. GKL

    GKL Active Member

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    Neat !

    .....now when it comes to the formulas for capacitive reactance or inductive reactance I sometimes need to refresh my memory to be sure :D

    IF I remember correctly (without checking) XL = 1 over 2 Pi FL and XC = 1 x 2 Pi FC (IF I remembered correctly :D)
     
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  15. GKL

    GKL Active Member

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    Thanks for the insight, It might possibly be that they are saying the ideal voltage for their radio is 13.8 and not that that is the limit, I'll have to research their radio more, I like to do a lot of research before buying electronic stuff so I can be sure it will fit what I need, I've had a pretty good success rate of not having to send stuff back when I do enough research first :D
     
  16. ChapmanF

    ChapmanF Senior Member

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    I think you swapped them. :)

    You can think about which way would give you an XL that increases with F (it is harder to pass higher-frequency signals through an inductor) and an XC that decreases with F (it is easier to pass higher-frequency signals through a capacitor).

    Did you get a spiel about ELI the ICE man?
     
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  17. GKL

    GKL Active Member

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    Thanks :D I knew that was a possibility as I think I swapped them before (that's what can happen when you are just trying to remember them and don't actually need to use them on a regular basis:D)

    Don't remember ELI the ICE man offhand, I think there was also other helps like that I can't think of right now.
     
  18. ChapmanF

    ChapmanF Senior Member

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    The voltage (E) in an inductor (L) leads the current (I) ... I in a Capacitor leads E. :)
     
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  19. GKL

    GKL Active Member

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    Neat way to remember that, thanks ! (as we get older the memory helps are even more appreciated :D)
     
  20. BiomedO1

    BiomedO1 Senior Member

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    You should probably track down that lighter circuit fuse; so you know where to find it - if you pop it. I believe that fuse is also tied to your USB charging ports and wireless charger - if so equipped. It's usually a 10A- 15A fuse.

    Hope this helps.
     
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