Another 12v Batt Thread - Low Voltage?

Discussion in 'Gen 4 Prius Main Forum' started by ekpolk, Jan 27, 2019.

Thread Status:
Not open for further replies.
  1. ekpolk

    ekpolk What could possibly...

    Joined:
    Jul 31, 2006
    548
    172
    0
    Location:
    Pensacola & Vero Beach FL
    Vehicle:
    2018 Prius
    Model:
    Two Eco
    My 2018 Two-Eco is only two weeks old to me, but it was built in January 2018, a full year ago. It got swapped between a couple dealers and sat through one southern summer rarely driven. It had only 100 miles on the ODO when I took delivery.

    The car is showing no symptoms of electrical malfunction, but I keep seeing a low voltage indication on my ScanGauge-II, which is still sitting temporarily (and sloppily...) atop the steering column. Here's the indication I see when I put the car in ACC mode (PWR pushed twice withOUT the brake pressed):
    [​IMG]

    If I kill the DRL/headlights, the volts jump to 11.9 or 12.0.

    By most sources, 11.8v is essentially near full discharge, assuming it's an accurate reading. Yet the car boots up fine and is offering no malfunction codes. Incidentally, the SG-II is great for codes too, you can read 'em all and look them up on line without leaving the car (which I did several times in the old car). You can also reset them.

    Any thoughts on this? This is by no means a panic-now situation. I'm thinking I'll take it to the dealer for a closer look/double check. I thought I'd consult here first and see if anyone has seen anything like this first. Thanks!
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    92,377
    41,787
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    scan gauge can do funny things if left hooked up. measure the voltage in the morning before entering the car, after sufficient driving the previous day.
     
    alanclarkeau likes this.
  3. alanclarkeau

    alanclarkeau Senior Member

    Joined:
    Feb 24, 2016
    6,602
    7,218
    0
    Location:
    near Brisbane, Australia
    Vehicle:
    2016 Prius
    Model:
    N/A
    Why are you worrying? It's normal. You wouldn't be doing that in ACC mode anyway.

    Did you watch this?



    Your battery is still under a huge warranty - check with the dealer.
     
  4. ekpolk

    ekpolk What could possibly...

    Joined:
    Jul 31, 2006
    548
    172
    0
    Location:
    Pensacola & Vero Beach FL
    Vehicle:
    2018 Prius
    Model:
    Two Eco
    True, I've used SG-II for about a decade now -- I practically feel naked without it... I haven't done anything this weekend. It's Sunday evening and I haven't driven the car since Friday evening (notice the stone cold coolant temp). In other words, the hybrid system has actually run in almost 48 hours, so this reading should be pretty settled down. The lights, inside and out, seem pretty strong, so it may well be some issue between the battery and the gauge. It would be nice to know how the computer is measuring and reporting this datum.
     
  5. alanclarkeau

    alanclarkeau Senior Member

    Joined:
    Feb 24, 2016
    6,602
    7,218
    0
    Location:
    near Brisbane, Australia
    Vehicle:
    2016 Prius
    Model:
    N/A
    As will ACC mode.
     
    bisco likes this.
  6. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    92,377
    41,787
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    good point.
     
    alanclarkeau likes this.
  7. ekpolk

    ekpolk What could possibly...

    Joined:
    Jul 31, 2006
    548
    172
    0
    Location:
    Pensacola & Vero Beach FL
    Vehicle:
    2018 Prius
    Model:
    Two Eco
    Again, it's more "proactive concern" than worry. And since the car is two weeks old (to me, it was mfr in 1/18 a year ago), the wty is no problem. I'm just in a place right now where I CAN NOT be late because of a car issue.
     
  8. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    92,377
    41,787
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    buy a cheap volt meter

    better yet, a jump pack
     
    Raytheeagle likes this.
  9. ekpolk

    ekpolk What could possibly...

    Joined:
    Jul 31, 2006
    548
    172
    0
    Location:
    Pensacola & Vero Beach FL
    Vehicle:
    2018 Prius
    Model:
    Two Eco
    Great video! Thanks for the suggestion. I'm going to have to watch more of those.

    A jump pack is a good idea. I'm presently doing training, eight hours away from my house, where all my tools are sitting -- useless, including my electric stuff. Probably more cost effective to just take it to the local dealer for a check-out. But I'm so addicted to gadgets, I'll probably end up getting a little meter too...

    Realizing that my SG is reading through the car's computer, my indicated voltage is 0.9 lower than the car in the vid. We'll see shortly.
     
  10. alanclarkeau

    alanclarkeau Senior Member

    Joined:
    Feb 24, 2016
    6,602
    7,218
    0
    Location:
    near Brisbane, Australia
    Vehicle:
    2016 Prius
    Model:
    N/A
    If you get bored - he's got one on the Hybrid battery (Li-ION only I think)


    He's got some good videos - long - on the Hybrid Synergy drive - he actually assembles it and describes it as he goes.

    [REALLLLLY short version]


    [short version]


    [Long version]


    Plenty of others too, inverter etc. "Evolution of the Toyota Prius Transaxle" is interesting.


    He's also got some non-PRIUS ones which I found interesting. Like the one showing the approx 400 parts which go into ONE CVT belt for a belt-type CVT.
     
    Raytheeagle likes this.
  11. ekpolk

    ekpolk What could possibly...

    Joined:
    Jul 31, 2006
    548
    172
    0
    Location:
    Pensacola & Vero Beach FL
    Vehicle:
    2018 Prius
    Model:
    Two Eco
    Alan, my wife hates you in advance! ;):p
     
    Raytheeagle likes this.
  12. alanclarkeau

    alanclarkeau Senior Member

    Joined:
    Feb 24, 2016
    6,602
    7,218
    0
    Location:
    near Brisbane, Australia
    Vehicle:
    2016 Prius
    Model:
    N/A
    :LOL::LOL::LOL:
    Good to watch technical stuff on YouTube - you don't have to clean your fingernails.
     
  13. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    92,377
    41,787
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    @Mendel Leisk has just the load tester for gadget addictions :cool:
     
    alanclarkeau and Mendel Leisk like this.
  14. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
    Staff Member

    Joined:
    May 11, 2004
    14,814
    2,480
    66
    Location:
    Far-North Chicagoland
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    There are multiple discussions going on about the 12v battery. Both of them already have some really good information. It would be best to add to those discussions than to further distribute information across yet another discussion. This is not a comment to the OP who started a new discussion about a new concern. Rather, this is an attempt to try and keep information easy to find for future Priuschatters who might find themselves sifting through pages and pages looking for information.

    You can find multiple 12v battery discussions here:
    12v battery voltage? | PriusChat
    Alternative to the 12v 45ah battery? | PriusChat
    How long will 12v battery last between drives? | PriusChat
    Is 12 Volt Gen 4 Battery Made of Gold? | PriusChat
    2016 Prius 2 Auxiliary Battery Replacement | PriusChat
    Best AGM 12V battery for Gen 4? | PriusChat
    12v battery maintenance when Prius is not driven for several days | PriusChat
    Will I Drain My Battery Leaving my Trunk Open? | PriusChat
    Please explain 12V system to me--how to keep battery charged while using accessories? | PriusChat
    What should a 12v battery cost me? dead after 56K mi & 23 months. Dealer says $458 | PriusChat
     
Loading...
Thread Status:
Not open for further replies.