12v Battery Is Discharging, Re-Charge Now !

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by Rob43, Apr 18, 2020.

  1. Hicksite

    Hicksite Member

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    Ok, thanks!
     
  2. bisco

    bisco cookie crumbler

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    idk what a new 12v should read in gen4. but in gen3, which is agm, it would be around 13 volts, and typically stay in the high 12's for quite awhile, then slowly drop over the years.
     
  3. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    Sidebar about cheap vs good meters. Watch this video. It's a good explanation of the differences and why you would want a Cheap Craftsman vs a $170 Fluke.
     
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  4. Salamander_King

    Salamander_King Senior Member

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    TLW... 41 min video! I will watch it later. LOL I ordered a voltage standard module from here. voltagestandard.com - Voltage Reference, Voltage Standard
    Yeah, it cost $31 + shipping which is more than the sum of all the cheap multimeters (I have 4 or 5 of them) put together. BUT, I was so curious to find out how bad or good those cheap multimeters are, without spending $395 on a Fluke multimeter.

    I have not received it yet. I will report back when I test and compare all the readings I am getting from the same 12V battery.
     
  5. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    Yes, it's long but there were some surprises. One of the big items is auto ranging on the more expensive vs the cheap. I have that same Craftsman he compares to. He has a good example of choosing the a range on the meter that looks logical, but shows how it can not give you a value unless you choose a range that was not logical. Watch at 15:00 for a big surprise.
     
  6. Salamander_King

    Salamander_King Senior Member

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    OK, I watched the video. The Craftsman model 82141 is the same multimeter as I have, but mine is probably quite a bit older than the one in the video. Mine is at least 15 years old. Anyway, I just checked a 120V outlet using my model 82141, it reads fine at AC 200v range as 119.7v and switching to AC 600v range reads 120v. I think the one in the video is just defective, not a bad design as the poster claims. On the video, I noticed the Fluke reads a 1.5v battery at 1.285v but the Craftsman was reading 1.615v. The discrepancy must be due to the inaccuracy of the cheap multimeter. But the poster does not make any comment on this finding.o_O

    By the way, did you mean to write "you would not want a cheap Craftsman" here? For the most part of what I use a multimeter, $10 Craftsman would work just fine, but yeah, if I can afford it, I would buy $395 Fluke 87V.
     
    #166 Salamander_King, May 2, 2020
    Last edited: May 2, 2020
  7. Salamander_King

    Salamander_King Senior Member

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    Here is my weekly report on my 12v battery monitor. The car was driven ~1.5 hours and plugged in ~2 hours EVSE plugin (the traction battery charged up to 43%) on 4/25. Prior to the driving, the car sat 1 week without any activity (no door opening, no fobs near).

    4/25 before drive: 12.49v 80%
    4/25 after plugin: 12.68v 100%
    4/26 day1: 12.57v 93%
    4/27 day2: 12.51v 85%
    4/28 day3: 12.46v 75%
    4/29 day4: 12.47v 76%
    4/30 day5: 12.42v 70%
    5/01 day6: 12.44v 71%
    5/02 day7: 12.42v 68%

    average drain: ~0.04v/day or ~0.3v/week

    At the end of 7 days, I took the car for another weekly routine drive ~1.5 hours and ~2 hours EVSE plugin (the traction battery up to 40%). This time the 12v battery was charged to 12.65v 99%.
     
    #167 Salamander_King, May 3, 2020
    Last edited: May 3, 2020
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  8. Mark57

    Mark57 2021 Tesla Model 3 LR AWD

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    I agree and that's the exact same Craftsman I have, like you. I don't need the $$$$ one. Just though it was an interesting comparison with a few details I'd not though about. Back to my cave, I'm out of here.
     
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  9. bisco

    bisco cookie crumbler

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    with all the 12v complaints, i'm surprised more owners aren't chiming in
     
  10. Salamander_King

    Salamander_King Senior Member

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    My take is if the battery is less than 3 years old and car is driven at last once a week for 30 min, it should be fine provided that during the period of inactivity there is no opening door, turning lights on, or fobs near the car, etc.
     
  11. bisco

    bisco cookie crumbler

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    it would be interesting to know the quiescent draw spec on the pip and prime. seems to be quite a bit different.

    my car can sit for days with sks on with no measurable drop with a cheap meter. it used to drop .3 volts over 9 weeks in winter.
     
  12. Salamander_King

    Salamander_King Senior Member

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    I can try disabling SKS in my car and see if that changes the drop rate? I don't know what else that may be using the battery in the car except for my BT battery monitor. I disabled SOS (Saftey Sense) so no telematics should be working.
     
  13. bisco

    bisco cookie crumbler

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    yeah, i would disconnect the monitor.

    doesn't sks shut off automatically after so many days?
     
  14. Salamander_King

    Salamander_King Senior Member

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    According to the manual it takes at least 5 days before the battery saving feature kicks in.

    Screenshot 2020-05-03 at 11.51.13 AM.png
     
  15. bisco

    bisco cookie crumbler

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    that would take a long test, but it would be interesting to see the daily voltage in the second week.
     
  16. Salamander_King

    Salamander_King Senior Member

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    Well, my weekly monitor shows virtually no drop in 12v SOC after 5 days. That may be due to the SKS battery-saving feature kicking in.

    4/26 day1: 12.57v 93%
    4/27 day2: 12.51v 85%
    4/28 day3: 12.46v 75%
    4/29 day4: 12.47v 76%
    4/30 day5: 12.42v 70%
    5/01 day6: 12.44v 71%
    5/02 day7: 12.42v 68%
     
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  17. bisco

    bisco cookie crumbler

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    and you can turn it off from the fob, yes?

    amazingly, it sounds like sks is the problem. must be ab increased draw. i wonder if it has something to do with the larger fob?
     
  18. Mendel Leisk

    Mendel Leisk Senior Member

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    Maybe CCA data points would be useful?

    Optima Yellow Top installed Sept, 2015: CCA: 645 (rated 450)
    Currently: CCA: 608

    And for phantom amp draw, on our 2010: 14~18 milliamperes, with spikes every 4~5 seconds to around 40. The spikes didn't seem to synch with the security icon blinking on the dash, but I would still suspect that's something to do with it.
     
    #178 Mendel Leisk, May 3, 2020
    Last edited: May 3, 2020
  19. Salamander_King

    Salamander_King Senior Member

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    Well, I thought I read somewhere that I can turn the SKS system off by operator customization. Looking it up in the manual, some settings are customizable from the MID menu, but it seems to turn SKS system off, it requires dealer visit (or DIY using Techstream or Carista?). Screenshot 2020-05-03 at 2.21.08 PM.png
    Screenshot 2020-05-03 at 2.21.22 PM.png
     
  20. bisco

    bisco cookie crumbler

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    huh, i could have sworn someone mentioned it. maybe the lift back? hard to believe they are different.

    maybe it was non usa
     
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