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Sentry mode vs long term battery degradation

Discussion in 'Model 3: Battery & Charging' started by davidl808, Oct 18, 2019.

  1. davidl808

    davidl808 Member

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    Sentry mode drains about 1 mile per hour, so if we leave it on for an entire year, it will use 8760 battery-equivalent miles. Over an 8 year period, Sentry mode will use 70,080 battery-equivalent miles, or 15% of a 75kwH battery pack's useful life assuming 1500 cycles / 465k miles.

    Is anyone concerned by this level of battery drain or do you brush it off?
     
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  2. apodbdrsM3

    apodbdrsM3 Member

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    I brush it off, I like sentry mode! But, I only engage it when I am parked some other than home.
     
  3. ucmndd

    ucmndd Well-Known Member

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    The good news is if you have sentry mode on for 8,760 hours a year like you suggest, you don’t need to worry about degradation at all because you haven’t driven the car, just parked it with sentry mode on for an entire year.
     
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  4. Tessaract

    Tessaract Member

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    I have serious doubts about the 1mile/h battery drain number. That would imply that sentry mode alone requires 240Wh/h = 240 W of power, which seems way out of the realm of reasonability. I think you should carefully check your consumption number first. i think it's way high.
     
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  5. ucmndd

    ucmndd Well-Known Member

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    240 watts doesn’t seem out of the realm of reason to me. As I recall from the autonomy day presentation, the AP 2.5 computer uses about 60 watts by itself. Plus the MCU and all the cameras? 200w seems perfectly plausible.
     
  6. Tessaract

    Tessaract Member

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    The cameras use almost nothing... they're just sensors.. think about your smart phone... would you think it reasonable that it's camera consumed 180W? Or even a quarter of that? No way. And the AP2.5 computer is doing way more "heavy computing" than running a couple cameras would. So I stand by my assertion: 250W is outlandish.
     
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  7. jjrandorin

    jjrandorin Moderator, Model 3, Tesla Energy Forums

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    If you test it, you will find that sentry mode uses about 1 mile per hour of usage. That number has been tested by several. Thats not even counting things like cabin overheat etc protection (which this thread doesnt talk about).

    I find the premise of the OP somewhat silly though, because its not mandatory to use sentry mode. If someone feels like they need to use it, then the power usage "is what it is". If they dont want the drain it currently has, they shouldnt use it. Posts saying "but I have to use it!!!" I find laughable.
     
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  8. ucmndd

    ucmndd Well-Known Member

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    Plenty of anecdotal evidence and observation to suggest about 1 mi/hr range loss is more or less what people are seeing.

    Like I said, AP computer, MCU - I believe in the model 3 both are liquid cooled, are they not? So now we’re talking a coolant pump too.

    I’ll stand by my assertion that ~200 watts is not unreasonable and matches up with real world observation.
     
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  9. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    It may well be outlandish, but that does not make it untrue. It’s the highest power consumption security system known to man. ;) Welcome to the world of Tesla.
     
  10. Darmie

    Darmie Supporting Member

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    I see your point but unsure if you are factoring in the biggest benefit from sentry mode. Most Perp are walking in off the streets eager to turn themselves in.
     
  11. Knightshade

    Knightshade Well-Known Member

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    I don't use sentry when the car is parked in my garage at home, so my numbers are more like ~40 hours the car is parked at work- (and honestly we still drive our ICE vehicle at least 1-2 days a week to work so that # is gonna be even lower real world- but let's call it 2000 hours a year for some time parked at stores, friends houses, etc).

    So 2000 miles a year... On a car with an expected 465,000 miles of life that's not, at all, a concern.
     
  12. Tessaract

    Tessaract Member

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    Well I did the experiment over the last 2 nights, and I gotta admit I need to eat some crow.

    First night, Sentry off: started 21:53 @ 224 km, finished 10:45 @ 221 km, drain = 3km
    Second night, Sentry on: started 21:50 @ 256 km, finished 10:46 @ 236 km, drain = 20 km
    So additional consumption from Sentry Mode is (20-3)/11hrs = 1.5 km/h or 231 W (at 150Wh/km)

    I'm surprised at the result, obviously, and wondering why Sentry Mode requires this much power. I doubt it's the AC system, cause temps here were about 4˚C overnight. There were 4 Sentry Mode alerts recorded (all of them me walking into the garage for one reason or another). I would expect perhaps a higher number of Sentry Mode alerts might also increase power consumption, but 4 alerts is a pretty small number.
     
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  13. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    I've never attempted to measure this, but I do wonder about this "observation." It does not make any sense that alerts would increase power consumption in any significant way, as it appears the car is always recording and in the same state when it is in Sentry Mode.

    I just wonder whether more alerts tend to correlate with a longer period of Sentry time activated (of course, it would be correlated). So people get the impression that they lose a lot of miles when there are more alerts...which they do...but only because Sentry was on for longer...that's my hypothesis.

    But who knows. As I said, haven't measured it. The more alerts meaning more power used just doesn't seem very plausible.
     
  14. Tessaract

    Tessaract Member

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    I haven't actually measured Sentry Mode power consumption with high and low number of alerts, so my comment was somewhat speculative. However, I can speculate a few reasons for higher power with more alerts: 1) Sentry Mode seems to flash marker lights whenever an alert is generated, which consumes some power. 2) Recording of actual video for each event consumes some power. 3) Sentry Mode may enter a higher power monitoring state when an alert happens.

    Whether the above are significant (from a power consumption perspective) remains to be tested. Stay tuned...
     
  15. Knightshade

    Knightshade Well-Known Member

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    Yes.

    Nope.

    Sentry doesn't record anything. Dashcam does.

    When Sentry goes to alert mode it just moves the last 10 minutes of clips that dashcam had already recorded from the recent folder into the saved folder. Has no impact, at all, on what is being recorded when.

    Only thing it does that'd take more power, besides the lights thing you mention, is the display turns on with the HAL eye and the message you are being recorded... the display obviously takes SOME power.
     
  16. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    True. I'll still be surprised if the energy consumption proves to be significantly higher due to triggers, unless the Sentry shows up with hundreds of triggers (where the display and lights are constantly on/flashing - that does seem like it would increase consumption a bit).
     

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