1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Dead 12v Battery --- A Glove Box Remedy?

Discussion in 'Gen 2 Prius Technical Discussion' started by Rokeby, Feb 8, 2008.

  1. Rokeby

    Rokeby Member

    Joined:
    Jan 21, 2008
    3,033
    708
    75
    Location:
    Ballamer, Merlin
    Vehicle:
    2008 Prius
    The number of dead 12v battery threads gives me cause for concern --- one of these days I'm sure to forget and leave something on all night. I used the search tool to find and read a half-dozen or so threads on this topic. I'm thinking of something that will fit in the glovebox. [Edit 9/02/08: See thread list below.]

    Distilling it all down, I have three questions:

    Will this device plugged into the under-dash 12v power outlet with the Coastaletech mod be useable to boot the CPU(s?) with a dead aux battery?

    http://www.amazon.com/exec/obidos/ASIN/B000H774BY/ref=nosim/8685595-20

    Power Outlet Mod

    If the above doesn't work, if I mod the B&D unit with alligator clips and use the jumper points under the hood, will that arrangement work?

    Will the start-up of the 'accumulator pump' ---whatever that is and does --- negate this whole approach?

    ****************************************************************

    Edit: January 15, 2010.
    First time viewers, I opened this thread on Feb 8, '08. Now, what appears to be a
    simple suggestion has, you will see if you read all the posts, turned into wide ranging
    discussion going from a simple and inexpensive string of D-cell batteries, to the
    complex and probably expensive tapping into the HV battery. To my knowledge none
    of the alternative suggested methods have actually be made and tested.

    There have more than 10,000 viewings of this thread. I remain convinced
    that, like me, many Prius owners want to find some safe, reliable, inside-the-car
    means to overcome the dead 12v battery that can result from a simple oversight or
    small mechanical or electrical malfunction.

    Going through all the postings makes for interesting reading. On the other hand, if
    you'd like to quickly see what the final result is, jump to post #60.

    Also, in posting #66, tmorrowus used the combination of the Black and Decker
    BB7B and Coastaletech always-on power port mod to restart his Prius with a dead 12V
    battery under controlled conditions. So, this little work-around really does function as I
    have hoped. I haven't yet had reason to use mine.

    Rokeby

    ---------------------------------------------------------------------------------------------
    By way of examples, below is what I am sure is a partial list of threads about the
    symptoms, causes, and possible results of failure of the 12V battery. It was put
    together by Bill Nolting, bnprius and appered in his thread,

    http://priuschat.com/forums/care-ma...-12v-battery-dies-4th-time-please-help-3.html

    Thank you, Bill.

     
  2. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
    19,891
    1,193
    9
    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
    Model:
    N/A
    It should, in theory, work. But I've never seen anyone post a first hand experience with it.

    Ultimately I'd recommend one of the combo jumper/air pump 12v outlet boxes. They have a larger battery and are more versatile since it can be used to adjust tire pressure as well.

    The 12v battery reports disproportionately suggest a problem. I've never had a 12v failure except at the end of my battery's life while listening to the radio for a time in the car in ACC mode.

    I have left the Prius parked for up to 13 days without being driven without it dying...in those cases I DO bring my jumper box 'just in case'. Otherwise it stays in my garage.
     
  3. icarus

    icarus Senior Member

    Joined:
    Apr 12, 2007
    4,884
    976
    0
    Location:
    earth
    Vehicle:
    2007 Prius
    Model:
    N/A
    If you are doing anything that requires your car to be jumped on any regular basis you are KILLING THE BATTERY!

    While a small jump start device may be a good idea for those rare emergencies, goo battery care is a way better investment! If the car is going to sit for more than a couple of weeks, a small trickle charger, or a small solar charger will keep the 12vt battery at full float voltage.

    The Hv battery will not be a problem if it goes down a bit over a few months. It will not sulphate like the flooded cell of the 12vdc battery.

    Once again, I suggest all those with battery questions to read and UNDERSTAND some of the following: http://www.batteryfaq.org/


    Icarus
     
  4. markderail

    markderail I do 45 mins @ 3200 PSI

    Joined:
    Sep 13, 2006
    2,260
    163
    18
    Location:
    Pierrefonds (Montreal) Quebec Canada
    Vehicle:
    2010 Prius
    Model:
    N/A
    Dead 12v - boosting how-to jumper cable story

    Happened to me yesterday.

    Rear parked against a snowbank on driver's side. Canada has Daytime Running Lights, that only turn off either :
    - manually
    - when auto, opening the driver's door when IG-OFF.

    So, in this order :
    1. Rear parked, tight spot, between snowbank and car
    2. Opened driver door to see if I could get out.
    3. Decided to stay put since my wife could get out on her side
    4. Closed my door, then turned off car
    5. Got out through front passenger door
    6. Went to work
    7. After work :eek: felt stupid

    Got a lift home, went back armed with my wife's Yaris, booster cables, and the ***wonderful*** reference material found on PriusChat.com.
    Like how to open the door when dead 12v battery, how to jumper - boost a dead 12 battery from the hood.

    The hardest part was figuring out how to open the fuse box.
    There's a damning -> arrow on the plastic pointing right - useless.

    To open the fusebox, it's due south, or due north, to unclip. Not much force required.

    Fun in -10c winter at nighttime with a poorly lit parking lot. Used my cellphone as a flashlight.

    Connect Red & Black to the Yaris (with motor off) battery.

    The 12v Positive screw is protected with a red plastic, lift, OMG a TINY screw. The cable booster pincer just barely attached.

    The black pincers to the body of car, and then . . .


    :eek::eek::eek::eek: The car alarm went off !!! :D

    Used the FOB to "open" the car.

    Then started the car normally, the HV Battery was fine, hardly used.
    Had to turn on the heat to start the ICE and have the ICE stay on.
    Remove the cables from the Prius. Then the Yaris.

    From then on, no problems. Including the Fuse Box Dilemma, Winter, -10c, this took less then 10 minutes to do.

    No need to access directly the 12v battery in the rear of the car, which for me, would have been impossible.

    [NOTE : Detailed story so that the PriusChat search engine can help others that fall in the same trap I did. Thanks for reading ;)]

    Personally I don't think an extra on-board battery for "emergency" boost is a good idea. A taxi can boost you, CAA or AAA, a friend. Easy to do.
     
  5. markderail

    markderail I do 45 mins @ 3200 PSI

    Joined:
    Sep 13, 2006
    2,260
    163
    18
    Location:
    Pierrefonds (Montreal) Quebec Canada
    Vehicle:
    2010 Prius
    Model:
    N/A
    [Edit: Haven't found a human powered car battery booster/generator. Anyone?]
    [Edit: Patent Opportunity?]

    Any human force device, would have to produce at least 13.5 DCV to trickle charge a dead 12v battery.

    For the Prius, if the main HV Battery is not dead, would not need many amps, just enough to boot the computer and quickly press the IG-ON & foot on brake. Then the HV battery takes over, the 12v is no longer necessary.

    I've seen human powered pumps / cranks, but they do 5.5 DCV for cellphones. They work well, I've used them at camping.

    So I'd see a human powered generator as a good solution for boosting a car, but as an added benefit could also do your cellphone with a volt redux adapter.

    If such a thing exists over at Canadian Tire I'll check it out.
     
  6. Rokeby

    Rokeby Member

    Joined:
    Jan 21, 2008
    3,033
    708
    75
    Location:
    Ballamer, Merlin
    Vehicle:
    2008 Prius
    Thank you Evan and icarus for your input.

    I checked out the batteryfaq. My reaction; Holy Cow! Given a month of Sundays, I might just get through it all. In the meantime...

    I'm trying to take a proactive, perhaps even preemptive, approach here. Other than driving my two month old Prius on a daily basis, I'm not doing anything, nor seen any signs, that would lead me to believe the 12v battery is in any trouble. Not at this very minute anyway.

    I'm looking to develop a procedure so that if my significant other approaches the car and touches the door handle and nothing happens she can get the car started quickly and easily. And if that doesn't work, then it's time to call AAA.

    Regardless of what she's wearing, who she's with, or where she is, I know for a fact that she's not going to get under the hood. Period. Forget any discussions about the complex interactions of the HSD, the CPUs, the what-cha-ma-call-its, thing-a-ma-bobs, etc. (That's what they're called, I looked it up in the owners manual, on page 5,437.) The come back goes something like; "Its a brand new car, I should just be able to get in it and drive. What do you mean I can be locked out on the street? Maybe we should have bought he Corolla/Versa/etc." A wholly not unreasonable line of argument.

    If at all possible, I want to develop a simple procedure that can be accomplished --- after using the mechanical key to open the door --- while sitting in the driver's seat. But first off, I need to identify the physical pieces to solve the puzzle.
     
  7. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,076
    523
    5
    Location:
    Phoenix, AZ
    Vehicle:
    2005 Prius
    Makes sense. Actually the unit you linked looks pretty good to me. It runs 18V/3Ah internally and can put out 12V at 7A for 15 min. This is probably enough to start the Prius immediately, but certainly after a few minutes. I think the only unknown is the Coastal mod and whether this will give you a clear enough path back to the battery. I would expect so, but you would have to try it and find out. For a ~$50 investment, I'd say its probably worth trying. If the coastal mod doesn't seem to do it, you could always run a dedicated wire back to the battery and stick a female outlet plug on the end. Maybe run it into the center console? The only real trick with any of these battery boosters is that you have to remember to plug them in every so often to top up the internal battery. At least with this one you can also charge from the 12V aux outlet, rather than having to take it out and plug it in.

    Rob
     
  8. SyCo

    SyCo Member

    Joined:
    Oct 18, 2007
    207
    17
    0
    Location:
    Quebec
    Vehicle:
    2005 Prius
    Model:
    N/A
  9. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
    19,891
    1,193
    9
    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
    Model:
    N/A
  10. Rokeby

    Rokeby Member

    Joined:
    Jan 21, 2008
    3,033
    708
    75
    Location:
    Ballamer, Merlin
    Vehicle:
    2008 Prius
    Mark,

    your story only reinforces my, now more than ever, strongly held belief that there will come a time, sooner or later, that I will have a dead 12v battery.

    Only by reading your post over a few times was I able to understand the small departure from your normal routine that was your downfall. It was getting out the passenger side door, wasn't it? (I've read in a 'need a trash container' thread that Toyota designed the center console so just this thing can be done! What the right hand givith, the left hand taketh away.)

    Typically, I get through the mundane parts of my day-to-day life using tried and true behavioral subroutines. But, every so often, usually when I'm in a hurry, some little glitch results in a small deviation, or the conditions are ever so slightly different. Unthinkingly I follow the subroutine. BAP! And I realize that I weren't really paying attention... a Homer Simpson moment.

    I'm sure that there are many more mysterious ways that the dead battery scenario can be called forth from where it lurks, waiting, ever so quietly in the dark.

    mrscrms,

    thanks for the encouragement. I've thought it might be a good thing to have 12v power port in the trunk? area. Maybe on the side opposite the battery, in the storage area. That way I could plug in a 12v tire pump with out climbing into the drivers seat. (No, I would not put a charger in the car and plug it in here)

    Yes, I too liked the charge-in-the-car feature. Just charge it on the AM commute once a month or so. (Must remember to unplug it when I get to work)

    syco.

    re:

    WEZA 12v FOOT CRANK PORTABLE POWER SOURCE



    Truly brilliant, but I can't see my SO doing that either. Thanks anyway... brilliant.
     
  11. okiebutnotfrommuskogee

    okiebutnotfrommuskogee Senior Member

    Joined:
    Mar 2, 2007
    1,813
    15
    0
    Location:
    Tulsa, OK
    Vehicle:
    2011 Prius
    Model:
    Two
     
  12. icarus

    icarus Senior Member

    Joined:
    Apr 12, 2007
    4,884
    976
    0
    Location:
    earth
    Vehicle:
    2007 Prius
    Model:
    N/A
     
  13. Rokeby

    Rokeby Member

    Joined:
    Jan 21, 2008
    3,033
    708
    75
    Location:
    Ballamer, Merlin
    Vehicle:
    2008 Prius
    okie..., and icarus,

    Early on I thought about an additional battery, but the arrangements needed for easy, and hopefully in-place, charging were beyond me. To get that, wouldn't there need to be a circuit or module that continuously monitored the battery and allowed it to be trickle? charged, but not let the battery be discharged during normal operation? Is such an item available 'off-the-shelf?'

    Could there be an easily accessible switch somewhere so that my SO wouldn't have to go through all sorts of gymnastics sprawled over the folded down seat back to get access to the battery under the carpet cover, carpet, compartment cover, etc?

    Because I was unable to even name the parts necessary for a reliable, rechargeable, in-place battery arrangement, I chose to open this thread with the off-the-shelf (Baltimore's own) Black and Decker unit.
     
  14. sandsw

    sandsw Member

    Joined:
    Feb 24, 2007
    99
    37
    0
    Location:
    Sydney Australia
    Vehicle:
    2010 Prius
    Model:
    V
    Hi all,
    I don't have a prius (yet), but I enjoy the forums.

    Back in the '60's when two-ways (and all radios) were valve models, a common issue was coming back to a flat battery. One solution that techies (read radio-tv serviceman) had was to have two 12 volt batteries: one to start the car and one to run everything else.

    Early adoptees had two generators; later on heavy duty diodes were used.

    Question:
    How much current and voltage does it take to boot the computer and drive the relays that actuate the HV battery? Most CPU's run on 5volts or less, so I guess the issue is the relays.

    I was thinking along the lines of some AA NiMh batteries trickle charged from the standard battery - with diode isolation so that the AA's wouldn't discharge along with the 12v system.

    Then provide a switch that would allow the AA's to boot the car.

    Would this kind of mod be feasible for the prius?

    Cheers
    Warwick
    and thanks for a great forum
     
  15. miscrms

    miscrms Plug Envious Member

    Joined:
    Aug 21, 2007
    2,076
    523
    5
    Location:
    Phoenix, AZ
    Vehicle:
    2005 Prius
    The first way I can think of to try and address this issue is with an isolator:
    Powerline Multi-Battery Isolator
    Add a second battery, and then a switch to parallel the two. The second battery gets automatically charged up every time the car runs, but is protected from being run down. My only concern is how much voltage will be dropped across the unit. The dc:dc converter output voltage is already a little on the low side (so as not to cook the sealed battery I presume).

    You could accomplish the same thing with the OPs aux power unit, if you could modify the coastal mod to give a push button mode switch (assuming it doesn't do that already). You would leave the small booster battery in the center console plugged into the outlet, so it would always charge up each time the car ran. In the default mode, the booster battery would be isolated every time you turn the car off. If you accidentally run your main battery down, you close the switch to activate the aux power port which then ties in the booster battery and away you go.

    The other way to address the problem is with an auto-disconnect switch like this one:
    PriorityStart - Stop Dead Batteries on Cars & Boats [Priority Start! Battery Protector]
    That way, any time your battery voltage falls to a certain point it will just disconnect it. This would have the added benefit of protecting the battery, which on the above method would still be over discharged and damaged. My only concern with a product like this is whether it will work as advertised with the voltages and small current demands of the Prius. It would have been nice if Toyota had built in something like this.

    Of course, there is also a pretty good chance you will hardly ever (if ever) need this. There are certainly a number of people who have had battery trouble, but there are a lot more who haven't. Of course you watch, tomorrow my battery will be dead :rolleyes:

    Rob
     
  16. icarus

    icarus Senior Member

    Joined:
    Apr 12, 2007
    4,884
    976
    0
    Location:
    earth
    Vehicle:
    2007 Prius
    Model:
    N/A
    I REALLY think this is a solution in search of a problem. While you can series the two batteries together, install a cheap blocking diode so that the "AUX" battery won't be run down, it does present another whole set of problems.

    Mixing battery types and sizes is very detrimental to both batteries, but more so for the BIGGER of the two. (For attribution look here: http://www.batteryfaq.org/

    The smaller battery will tend to equal the capacity of the larger. The charge rate of the alternator will tend to be too large for the small battery as well.

    For all the trouble of all these idea, good battery maintenence and care, and a AAA membership would be money well spent.

    Icarus
     
  17. Rokeby

    Rokeby Member

    Joined:
    Jan 21, 2008
    3,033
    708
    75
    Location:
    Ballamer, Merlin
    Vehicle:
    2008 Prius
    As the original poster of this thread I've found the replies to be generally helpful. I applaud the many responders for their candor and helpfulness.

    I now believe that the combination of the Black and Decker aux power source and the Coastaletech mod have a good probability of providing the services that I'm looking for.

    Amazon.com: Black & Decker BB7B Simple Start 12-Volt Battery Booster: Automotive

    Power Outlet Mod

    As a second-best arrangement --- a very distant second-best for reasons noted early in the thread --- hooking the B&D booster to the under-hood charge points should also be workable.

    The later posts involving a second 'full size' aux battery have been helpful too, if only to illustrate that this option has its own set of conditions that must be met to be successful. For me, the added expense and complexity moves that option into the non-starter class. ;)

    I'm perfectly happy reading additional inputs, even those that by their very nature --- technical complexity and/or additional cost --- I am unlikely to implement.

    I joined PriusChat to learn about my Prius, and this I am doing, one post at a time.
     
  18. frosh

    frosh New Member

    Joined:
    Jan 17, 2008
    35
    0
    0
    Location:
    Virginia
    Vehicle:
    2007 Prius
    I still believe, the Prius is jumpable by 8 size D batteries through the aux port.
    Even if the car appeared dead, in my case the bat still had a couple of Volts that were enough to switch on all the relays and I believe the glovebox aux port would have taken the extra battery energy supply back to the car circuits. Didn't have the chance yet to test that. My Prius is 8month, replacment bat is about 4 month old.

    If the battery is dead-dead, surely only a jump at the charge points would help.

    My repeated issue is, that if the car isn't locked overnight I might have an empty battery next morning.

    frosh
     
  19. eestlane

    eestlane Member

    Joined:
    Sep 29, 2007
    110
    11
    0
    Location:
    Space Coast, FL
    Vehicle:
    2007 Prius
    The Prius has a feature that on my '95 Chevy Lumina was called a "Battery Saver" (at least my 07 Prius does). If any door, including the hatch, is not totally closed the interior lights will automatically go out in 15 to 20 minutes thus "saving your 12V battery". This feature does not apply to any manually switched on lights, like the reading lights in front or the trunk light. Therefore, if you manually switch the reading light on and forget it, the battery will drain. Also, if your trunk light switch is in the ON position, and the trunk is not fully closed, the battery will drain. Therefore, the thing to do is to leave your trunk light switch in the OFF position until you really need it, and immediately turn it off when it's no longer needed. Also, don't leave the reading lights on. I have tested this feature with the door and trunk lid activated passenger compartment lights on, and it works every time.
     
  20. eestlane

    eestlane Member

    Joined:
    Sep 29, 2007
    110
    11
    0
    Location:
    Space Coast, FL
    Vehicle:
    2007 Prius
    The Prius has a feature that on my '95 Chevy Lumina was called a "Battery Saver" (at least my 07 Prius does). If any door, including the hatch, is not totally closed the interior lights will automatically go out in 15 to 20 minutes thus "saving your 12V battery". This feature does not apply to any manually switched on lights, like the reading lights in front or the trunk light. Therefore, if you manually switch the reading light on and forget it, the battery will drain. Also, if your trunk light switch is in the ON position, and the trunk is not fully closed, the battery will drain. Therefore, the thing to do is to leave your trunk light switch in the OFF position until you really need it, and immediately turn it off when it's no longer needed. Also, don't leave the reading lights on. I have tested this feature with the door and trunk lid activated passenger compartment lights on, and it works every time.