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Jumping 12V Battery direct from Battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Chodronish, Jul 11, 2020.

  1. jzchen

    jzchen Newbie!

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    I posted evidence that 6 A setting was too fast for this battery. No matter how many times I started charging, it started charging because battery was not fully charged.

    So how does said smart charger know how quickly to charge a battery, does it ask you to input the size in CCA or CA? It doesn't know. Have you confirmed that 6A is not too high of a setting. I feel like I confirmed it was too fast. Like I said once I switched to below 4.2 A rated charge rate, it fully charged. Subsequent attempts to charge showed battery was full.

    I don't dare stick a higher rated charger on the 46B24R size. I'm afraid no matter how you pat yourself on the back that you're right, it's just going to damage the darn thing if someone follows your advice. I'm glad the OP listened and purchased something with an appropriate rating.

    With the experience I've shared:

    1. Kept trying to charge at 6 amp setting
    2. Electrolyte discharge at 4 A charger rate.

    Would you dare stick anything higher than 4.2 A to charge your own?...

    moto g(7) power ?
     
  2. jzchen

    jzchen Newbie!

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    Just an FYI, we got to go to our Azusa Costco today, but did not see the Duracell unit in stock, which was $39.99 in store vs $49.99 on their website. ($10 cheaper in store, my apologies if the prices aren't accurate, the relative difference is).

    moto g(7) power ?
     
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  3. SFO

    SFO Senior Member

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    Sounds like the smart charger is a tad bit too smart, and if it doesn't see a minimum voltage (10v?) it won't start to charge. This is why having an older dumb charger that can do both 6/12v around can be handy, first you would use the "dumb charger" to bring the low voltage battery up to a voltage that is recognized by the "smarter" charger so that it can take over.

    This link below won't be very useful for the OP, but it basically explains the issue at hand (please ignore the optima part, unless you're a fan person of such) : Bring Your Optima Battery Back from the Dead | The Streetside Garage
    Many of the major auto parts stores will install for little ($10?) or nothing, best to call around and ask about product availability and installation costs before hand. Costco won't install, period.

    If a walmart has an attached auto center, they claim free installation on any new battery purchased there. Best to confirm as above.

    Pepboys also claims to offer free installation, and they often have the best price after rebate(s). Best to confirm as above.
     
    #43 SFO, Jul 16, 2020
    Last edited: Jul 16, 2020
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  4. sam spade 2

    sam spade 2 Senior Member

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    No of course not. (y)
     
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  5. sam spade 2

    sam spade 2 Senior Member

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    AND.....I posted an answer explaning WHY that happens.....but you aren't listening.
     
    #45 sam spade 2, Jul 16, 2020
    Last edited: Jul 16, 2020
  6. sam spade 2

    sam spade 2 Senior Member

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    I'm not new at this game.
    I am an Electronics Engineering Technician and have been charging batteries for close to 60 years.

    Yes, I have used chargers rated at 40 amps on batteries smaller than the ones in a Prius.
    BUT I don't do that blindly.
    IF the charging rate doesn't come down quickly after connecting, I go to plan B and find a smaller charger........AND suspect that the battery probably is shot.

    The bad experiences that you relate when charging your batteries indicate that the BATTERY IS DEFECTIVE, probably beyond recovery and does NOT indicate a simple case of charging too fast.
     
  7. sam spade 2

    sam spade 2 Senior Member

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    Don't give up just yet.
    First, be SURE that you are connecting the charger right.
    Then try connecting to the battery first BEFORE plugging into the wall.
    Then try plugging in first and connecting to the battery second.
    Sometimes after a few failures, it will continue with the charge.

    Either way you will need a new battery.
    And almost no shops will "deliver and install".
    Are you a member of an Auto Club ?
    Does your car insurance include "roadside service" ??
     
  8. ttou68

    ttou68 Active Member

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    Jumping a Prius 12V battery is no different than any other vehicle's 12V battery, just make sure positive and negative posts are correctly connected..
    Once you have your Prius running, you can take it to an auto parts store and have your battery health checked.. if needed, and usually big name auto parts store would install it for free when purchased a battery from them..
    Or if your battery is just low on charge, then you can purchase any battery charger/maintenaner of your choice, just to make sure the settings are correct and Toyota recommend 4.2A charger for your battery. But I've use an old battery charger with setting on 6A/2A without any issues.. I just checked it periodically once every hour or so to see it battery is getting hot, and make sure you're charging it in a ventilated area..

    Posted via the PriusChat mobile app.
     
  9. sam spade 2

    sam spade 2 Senior Member

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    Toyota does NOT "recommend a 4.2 amp charger".
    They recommend that you not charge it at a rate higher than 4.2 amps.
     
  10. ttou68

    ttou68 Active Member

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    Actually Toyota do have a charger for it. It's rare to see one, I'll have to look up that battery charger and will post a photo if I can find it..
    And like I said it before there's no difference in charging a Prius 12V battery then any other vehicle's 12V battery..
    Here is a video on Gen 2 12V install..

    Watch "2nd Gen Prius 12V Battery Installation Step by Step Tutorial" on YouTube


    Posted via the PriusChat mobile app.
     
    #50 ttou68, Jul 16, 2020
    Last edited: Jul 16, 2020
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  11. Chodronish

    Chodronish Member

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    @samGreat ideas and yes, actually, my car insurance does include roadside service. Didn't even think of that. So even if I get this thing to charge with your suggestions, I'll still need to replace it? @SFO, interesting about the smart charger vs. dumb charger. I would get a dumb charger except it would be pointless if I still need to replace the battery. @jzchen, I know the hybrid battery is the more dangerous, but knowing nothing about batteries, the instructions with the battery charger scared me with things like: "WARNING: RISK OF EXPLOSIVE GASES. WORKING IN VICINITY OF A LEAD-ACID BATTERY IS DANGEROUS. BATTERIES GENERATE EXPLOSIVE GASES DURING NORMAL BATTERY OPERATION. FOR THIS REASON, IT IS OF UTMOST IMPORTANCE THAT YOU FOLLOW THE INSTRUCTIONS EACH TIME YOU USE THE CHARGER." :-O It also says "Do not continue attempting to charge this battery. Check the battery and replace, if necessary," which seems like weird instructions..... "bad battery," "do not continue attempting to charge this battery," but I also need to "check the battery and replace, IF NECESSARY"?! I fear the instructions with this battery charger are as bad as the instructions with most everything else I have ever purchased.

    I must say how much I appreciate all you people who know so much about batteries taking the time to help someone as clueless as I am about all this. I think I'm the equivalent of people in the early days of computers who would call technical support and complain their drink holder (CD player) broke off, or who thought their mouse was a foot petal.
     
  12. Chodronish

    Chodronish Member

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    @ttou68, thanks for that thorough video. Though probably a very simple procedure for a DIY person, I can see several points where I would very likely mess this up (when, not if, I drop bolts into crevices, tighten things incorrectly, don't have enough strength to get that one thing back on, etc.), and it would take me probably all day and I would have managed to damage the battery probably. Then there's the whole part where the neighbors would hear me screaming and threatening the battery and maybe call the police, so that would become a whole thing....
     
  13. Chodronish

    Chodronish Member

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    Seeking recommendations for 12V battery to purchase.
     
  14. jzchen

    jzchen Newbie!

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    Someone mentioned I should have more respect. So, with that in mind, I'm sorry if I've been disrespectful.

    I have the Toyota instructions on how to test the AGM battery. Charge it, "turn on high beams for 30 secs to remove surface charge. Measure voltage at the terminals with a V-meter." Reading said 12.46 V IIRC. So I kept it, as a borderline battery I may use in my iQ or the Prius v just in case....

    moto g(7) power ?
     
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  15. Chodronish

    Chodronish Member

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    @sam spade 2 - It's looking promising! I did as you suggested and counter to the instructions with the charger, I plugged the charger in first and then connected it. It initially read analyzing and charging 0% as before, but before it went to the bad battery message. Now it reads "charging - 55%."
     
  16. sam spade 2

    sam spade 2 Senior Member

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    As you have now discovered, most people have no need for two.
     
  17. Chodronish

    Chodronish Member

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    @sam spade 2 Wonder why the instructions said to not plug in charger first then that's what worked? Anyone have any recommendations for brand of battery?

    The battery is fully charged as of this morning, according to the charger. So I still need to get a new one we think? Or how do I tell?
     
  18. jzchen

    jzchen Newbie!

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    Try to charge it again. Once it's fully charged disconnect the charger leads and turn on high beams for 30 secs. Measure voltage at terminals. (Hoping you have a multimeter). Should be 12.5 V or above.

    moto g(7) power ?
     
  19. Chodronish

    Chodronish Member

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    @jzchen Thanks for the answer. Unfortunately, I do not have a multimeter, nor do I know what one is. The battery is fully charged now, according to charger. I think there is a way I can check the voltage on the 12V through a secret information screen. I'll look into how to access that.
     
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  20. bisco

    bisco cookie crumbler

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    close your eyes, clasp your hands, and stamp your foot three times...
     
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