2007 Prius - trickle charging 12v battery overnight

Discussion in 'Gen 2 Prius Technical Discussion' started by tampaite, Oct 11, 2017.

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  1. tampaite

    tampaite Member

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    Took our 2007 Prius(regular) for an oil change yesterday and dealer recommended that I replace the auxillary battery(12v) as it was going bad and wanted $315 for parts plus labor and taxes.

    I was a bit hesitant since the car was driving fine. well, be hold this evening, the car wouldn't start. Using the fob key, i was able to open the doors and when I insert it and hit the start button, nothing comes up on the dash board. I was like gosh, should have changed it.

    After 2 hours of doing nothing, was able to start but as soon as I powered down, it won't start again.

    The battery is the original I believe but I don't know if the first owner changed it(am the 2nd owner who purchased the car with 90K miles on it and it has 175K now).

    Using multimeter, i checked the voltage reading and it showed 4v so the 12v battery likely has to be replaced.

    Anyway, I see Amazon has the Optima battery for $140ish plus tax and with 2-day shipping total comes up to $175.

    I want to charge the 12v overnight and see if that helps.

    I have a Schumacher charger and is the settings below correct?

    1. Battery size = 2A or 8A or 12 A. I believe 2A is recommended
    2. Battery Type = Standard or AGM or GEL. I believe AGM is recommended.

    Should I leave for 6 hours or 8 hours or more?
     
    #1 tampaite, Oct 11, 2017
    Last edited: Oct 11, 2017
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  2. bisco

    bisco cookie crumbler

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    affirmative.(y)
     
    #2 bisco, Oct 11, 2017
  3. tampaite

    tampaite Member

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    Thanks.

    After charging for 20minutes, voltage reading changed from 4V to 13.3V

    How much more longer to charge? Should I really leave it overnight for another 6 to 8 hrs?
     
    #3 tampaite, Oct 11, 2017
  4. edthefox5

    edthefox5 Senior Member

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    I wouldn't waste my time. At 4V its toast. Spend your energy pulling it put.
     
    #4 edthefox5, Oct 11, 2017
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  5. edthefox5

    edthefox5 Senior Member

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    Take the charger off....with the car off turn on the headlights...measure the dc voltage at the front jump points.
     
    #5 edthefox5, Oct 11, 2017
  6. Mendel Leisk

    Mendel Leisk MMX GEN III

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    You should maybe get a smart charger, on in the 3~4 amp range. With these you can hook them up, they run through a charging program, and: they can be left on indefinitely if you want, no need for guesswork. Once it's done with the charging program it just trickle charges, and it's indicator lights show the status. My usual is the CTEK 4.3, there are a lot of similar chargers out there.

    Another tool worth considering, if your pockets or deep enough, is a meter like the Solar BA5. You input various statistics about the battery, basically it's type and rated CCA, then it does an electronic load test, and displays the battery's actual CCA, as measured, and gives a verdict: good, good but needs charging, or failed.
     
    #6 Mendel Leisk, Oct 11, 2017
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  7. tampaite

    tampaite Member

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    Update: After 1.5 hours of charging, the charger still shows 13.3volts or 71% charged.
     
    #7 tampaite, Oct 11, 2017
  8. SFO

    SFO Senior Member

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    Keep up the good work; doubt there is anything you might do that will degrade the battery at this point (y)
     
    #8 SFO, Oct 11, 2017
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  9. bisco

    bisco cookie crumbler

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    when it's done charging, check it after 12 hours. if it's below 12.4v, recycle it.
    but to be safe, get a new one, hard to say what a battery will do after it has discharged to 4v. most likely leave you stranded someday.
     
    #9 bisco, Oct 12, 2017
  10. jerrymildred

    jerrymildred Senior Member

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    With a voltage as low as what you had, I'd say it's shot.

    If you get it charged enough to run and you're not too far from Lutz, go see Todd at Contact Us - Tampa Hybrids Inc.. Might want to call first to check price and inventory, but he can probably offer you a better price on a new Toyota battery if you want the OEM. Nothing against the others, but the OEM is an excellent battery and I think it's worth the price difference. But he does have others available.
     
    #10 jerrymildred, Oct 12, 2017
  11. mmmodem

    mmmodem Senior Taste Tester

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    I got myself one of these to avoid being stranded. It's also an air compressor, USB charger, and flashlight for a pretty reasonable price. This could tide you over until the battery arrives.

    Only problem on a Gen 2 was I had to hook up directly to the + and - battery terminals. The remote jump points underneath the hood did not work. This required climbing into the trunk from the back seat to open the hatch using the emergency release.

    Stanley 'FatMax' 700-Amp Peak Jump Starter with Compressor #J7CS - Walmart.com
     
    #11 mmmodem, Oct 12, 2017
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  12. tampaite

    tampaite Member

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    20171012_061426.jpg
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    20171012_062641.jpg

    20171012_062730.jpg

    6AM Update: Charged it for about 7 hours and battery charger showed 100% charged and when I measured, it showed about 12.5v(Sorry, I have an analog multimeter).

    I drove around the neigbourhood(2 minute drive) for quick check.

    Am attaching few pictures to help others.

    First two were right after the battery was charged and it shows a red triangle in the background and also in the display it says "There is a problem with the transmission "P" lock mechanism...." and battery showed 14.2v and at this point the battery charger wasn't disconnected.

    The third photo is when I shut down the car and just hit the power button once and it shows 12.4v

    The fourth photo is when I applied a load by turning on the head-lights and it fluctuated between 11.4v to 11.9v before settling at 11.8v

    I drove to work(40 mile one-way) and no issues, will post an update later this evening.
     
    #12 tampaite, Oct 12, 2017
  13. xliderider

    xliderider Senior Member

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    Don't rely solely on battery voltage readings. My oem battery read 12.7 volts after charging, but lost capacity to start the car and couldn't even unlock the doors, the solenoids in the door lock actuators didn't have enough power.

    Get your battery load tested. Walmart, Sears, etc. have battery testers and will give you a printout of the condition of your battery.

    Posted via the PriusChat mobile app.
     
    #13 xliderider, Oct 12, 2017
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  14. jerrymildred

    jerrymildred Senior Member

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    You definitely need a new battery. Get it load tested to be sure, but I can almost guarantee it will fail the test. Did you call Todd yet?
     
    #14 jerrymildred, Oct 12, 2017
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  15. tampaite

    tampaite Member

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    6Pm update:

    Car was at work parked for 8 hrs, started fine no issues. Stopped on the way at grocery store and post office and it started again.
    Reads 14.1v during the drive and at 12.4v at rest.

    How long to monitor before I say it's good? I guess load testing will help but am not sure if walmart, sears can do load test on an AGM batttery. Anyone did the load test at those places?
     
    #15 tampaite, Oct 12, 2017
  16. Mendel Leisk

    Mendel Leisk MMX GEN III

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    How are you measuring that 12.4, via the car's displays? This'll continue to muddy the waters. If you can obtain an inexpensive ($20~) multimeter and get a reading with the right off (at jump point or battery posts), preferably after sitting overnight, you'll have a better idea. If it's reading 12.4 under those conditions, so soon after charging, probably replacement time.

    Battery retailers should be capable of doing a digital load test, phone and ask. Again, Solar BA5 is a decent DIY tester, around $60.
     
    #16 Mendel Leisk, Oct 12, 2017
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  17. edthefox5

    edthefox5 Senior Member

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    The jump points have to work there whats powering the car. Those points supply power to the main fuse box. Where did you hook the ground clamp when you tried to hook to the jump points?
     
    #17 edthefox5, Oct 12, 2017
  18. edthefox5

    edthefox5 Senior Member

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    Some people can't be helped.
     
    #18 edthefox5, Oct 12, 2017
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  19. tampaite

    tampaite Member

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    woh you have great attitude buddy - thanks

    Anyway, the closest sears/walmart is about 20miles so went to Auto Zone, did a load test, it failed(showed 8.5v). Then had to wait 30 min for someone to jump start it as am a non-paying customer, make sense.

    Ordering from amazon tonight.

    Placed an order for Optima DS46B24R , $138 + tax and will have it on Saturday.

    Thanks but i've had not so good experience with Todd so won't be calling now but will keep his details handy.

    Question: I noticed that when Auto Zone did the test, they disconnected the negative terminal of the battery to do a load test and this resulted in the clock resetting to 1:30

    I was going over my photos - i usually take a photo of the dash after every oil change and noticed that the time was reset as well. Is there any plausible reason why the dealer may have reset the clock and also Trip meter A and B ?
     
    #19 tampaite, Oct 12, 2017
    Last edited: Oct 12, 2017
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  20. Prodigyplace

    Prodigyplace 2025 Camry XLE FWD

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    Did they drain the battery by listening to the radio with the car in ACC mode?
    Some people who have had work performed on their Prius have had similar issues.
     
    #20 Prodigyplace, Oct 12, 2017
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