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Best 12v Battery

Discussion in 'Gen 2 Prius Main Forum' started by Metrolens, May 15, 2018.

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  1. Metrolens

    Metrolens Member

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    What is the latest intel on a good 12v battery for a Gen2? I have a 2005 and I most recently replaced my 12v battery back in late 2012, so it's likely soon going to be due.

    How's this one - the AC Delco ACDB24R? At $158, with good reviews, seems a good choice?

    I've read conflicting reports about the Optima Yellow Top. And the OEM battery seems very expensive.
     
    #1 Metrolens, May 15, 2018
  2. DMC-5180

    DMC-5180 Active Member

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    I bought my 2005 in fall of 2013, I did not put the car into service till the following spring. At that time, I replaced the 8.5 year old OE 12 v battery for piece of mind insurance. I got a great deal on A yellow top optima that April which also came with a spring special deal of a free optima 400 charger or $100 off the Optima 1200 charger. I already had a 400 charger so I took the deal for the 1200 charger. The Optima is now 4 years old and I’ve put 155k on it since purchasing it. I have accidentally drained the 12v twice in that time. No I’ll effects that I can tell, besides the yellow top is a deep cycle battery. So the couple complete discharges didn’t hurt it anything.


    iPhone X ?
     
    #2 DMC-5180, May 15, 2018
  3. bisco

    bisco cookie crumbler

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    there really is no consensus. i would stick with oem because i have had 3 great experiences with them, and the warranty is pretty good. but i'm sure the delco will be fine if it fits correctly and has the vent tube fitting, but i don't like buying batteries on line in case i need to return them.

    what did you buy in 2012? whatever you choose, make sure the date code is within a few months, and it has a full charge.
     
    #3 bisco, May 15, 2018
  4. Metrolens

    Metrolens Member

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    In 2012 I bought OEM, installed at the dealer. Cost was $307 ($200 for the battery and a steep $100 for labor). Can I buy an OEM battery somewhere other than a dealership? And install it myself?

    And, that Delco has the vent tube fitting; it's apparently designed for the Prius. I also saw on another thread that JC91006 has one in his Gen 2, and it's working flawlessly.
     
    #4 Metrolens, May 15, 2018
  5. bisco

    bisco cookie crumbler

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    no, and yes, fairly easy install and plenty of you tubes. call around for pricing, ask for discounts.
     
    #5 bisco, May 15, 2018
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  6. Metrolens

    Metrolens Member

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    Lately I've noticed slightly reduced MPG in my 117k 2005 Gen2. Down from around 47 MPG to around 44 MPG, nearly all city driving, mostly short trips of <10 miles. Neither of these MPG numbers is really that bad, I believe, but I want to explain it. I can feel the Hybrid battery needing more help from the ICE, it's subtle but I have observed the ICE kicking in a little sooner than before.

    The two main factors that may explain:
    1. The 12v battery is old, as mentioned above; last replaced in 2012. (SEE BELOW for November 2017 test results)
    2. I put brand new tires on around 1k miles ago. They are LRR, Yokohama Avid Ascends.

    I also just changed the engine air filter, but saw no improvement. There is new oil around 1k miles ago, not overfilled.

    So, does the drop in MPG most likely point to the new tires, the 12v battery age, or perhaps something else?


    12v TEST RESULTS from Nov 2017:
    Here are the 12v test results (test from SpaceCityHybrid) which I ran on the 12v back in Nov 2017, when I had to replace my hybrid battery. I imagine the 12v is now weaker than these results, it now being 7 months older.

    - Press “Vehicle Signal Check” - the battery voltage is shown and should be about 12.4 to 12.8 Volts (normal for an unloaded battery)
    RESULT: 12.1v. A little weak, but not drastic?

    - Again without brake pedal, press Power button and release to put a current load on the battery - the voltage should stay above 12.0V (if less than 12.0V the battery is not well, or there is a fault or unusual load somewhere)
    RESULT: 11.8 v. Again, a little weak, but perhaps not drastic?

    - Press brake pedal and press Power button once to enter "Ready" mode - the battery is now charging at about 14V (if less than 13.6V or more than 14.4 there may be a problem with the charging circuit)
    RESULT: 14.0v. Seems good.

    So, these results show the 12v is a little weak, but not drastically so.
     
    #6 Metrolens, Jun 5, 2018
    Last edited: Jun 5, 2018
  7. bisco

    bisco cookie crumbler

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    i think it is getting drastic, but i rely on a voltmeter at the jump points. anything below 12.4 there and i'm replacing it.
    however, i don't think that explains what you're experiencing. more likely a 13 year old hybrid battery.
     
    #7 bisco, Jun 5, 2018
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  8. Metrolens

    Metrolens Member

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    Do you mean the initial reading should be 12.4 or higher? (I have it as 12.1 above, which is low).

    And, to clarify, I replaced the hybrid battery in November 2017 with a reconditioned battery from Electron Automotive. The recon battery is from 2013 modules (and btw I have a 6 year warranty on it).
     
    #8 Metrolens, Jun 5, 2018
  9. bisco

    bisco cookie crumbler

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    i mean if you put a meter on the jump point with everything off, 12.3 is low. i don't know how to interpret the mfd reading because i din't know what the draw is.

    have you noticed the hybrid battery needing more help since you installed it or before?
     
    #9 bisco, Jun 5, 2018
  10. Metrolens

    Metrolens Member

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    After the hybrid replacement, there was no drop in MPG until now. Which points to the tires (the most obvious culprit?), or the 12v which I already know is old and possibly overdue for a swap.
     
    #10 Metrolens, Jun 5, 2018
  11. bisco

    bisco cookie crumbler

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    if it happened as soon as you replaced the tires, it is obvious. new tires have a larger diameter and affect the odo.
     
    #11 bisco, Jun 5, 2018
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  12. Metrolens

    Metrolens Member

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    I tend to agree. And a 4-5 MPG drop has been mentioned as a likely outcome for new tires, so I think this is probably the answer.

    For sake of discussion, I just ran the above 12v tests, and got the following results. They are slightly BETTER than the test results I saw back in Nov 2017:
    1. 12.2v
    2. 11.9v
    3. 14.0v
     
    #12 Metrolens, Jun 5, 2018
  13. bisco

    bisco cookie crumbler

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    you can throw out number 3,that just means the inverter is charging the battery. again, 1 and 2 are a bit low, but things are on in the car, so static would be higher.

    i know toyota has a chart for those numbers, but idk where to find it.
     
    #13 bisco, Jun 5, 2018
  14. Metrolens

    Metrolens Member

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    I also just tested with an analog Multimeter via the jump terminals, and with the car off, it read exactly 13.0v. Which means the 12v battery seems to be plenty healthy, right?
     
    #14 Metrolens, Jun 5, 2018
  15. bisco

    bisco cookie crumbler

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    that's too high, surface charge. measure it in the morning before opening any doors. pop the hood the night before.
     
    #15 bisco, Jun 5, 2018
  16. Metrolens

    Metrolens Member

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    I re-read using the multimeter via the jump terminals today, and it came out around 12.8v. So still very healthy, apparently.

    That said, I went ahead and ordered the AC Delco battery I mentioned above - the price dropped to $149, which seems a pretty great deal. I figured even though my current 12v battery is still behaving very well, it is 6 years old and could (should?) crap out somewhat soon. So I'd rather change it out now before there is a problem, especially during a big road trip through the desert in the summer.

    Will report back once I have it installed.
     
    #16 Metrolens, Jun 6, 2018
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  17. bisco

    bisco cookie crumbler

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    sounds like a good idea. mine is also 6 years, reading 12.7 volts. i'm gonna ride her til she quits, but we don't get the heat except for a month or two.
     
    #17 bisco, Jun 6, 2018
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  18. Lucifer

    Lucifer Senior Member

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    Trickle charge the new battery overnight.
    If the mileage doesn’t go to a level you want and you want the mileage.
    Get a new factory traction battery.
    Run the tires at 40+- lb of air.
    Make sure the emergency brake isn’t rubbing.
     
    #18 Lucifer, Jun 6, 2018
  19. bisco

    bisco cookie crumbler

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    lubricate the fernalswanger.;)
     
    #19 bisco, Jun 6, 2018
  20. Metrolens

    Metrolens Member

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    Thanks. The recon battery hasn't shown any issue; really, so I am hoping it's not that as I just installed this one in Nov 2017.

    Tires are at 42/40, as always.

    Emergency brake isn't on.

    Should I retract the land anchor while driving? That might be causing some MPG loss.
     
    #20 Metrolens, Jun 6, 2018
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