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Battery maintainer?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by whataboutbob, Nov 30, 2023.

  1. whataboutbob

    whataboutbob Junior Member

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    I have a Prius 2010 and tend to travel for up to 3-4 months at a time, on the last trip, the battery was dead, so I like to prevent that. Based on quick searches, it sounds like I need a battery maintainer, has anyone used one before? I live in San Francisco Bay Area, so the winter shouldn't be too cold but in the summer, it can get really hot, in fact, it got so hot this summer that the phone holder attached to the windshield melted, my car was parked outside. However, I plan to park it inside a garage now but worry that the device might start a fire if it gets too hot in the garage, is that a concern?

    Found this device on Amazon, would it work?
     
    #1 whataboutbob, Nov 30, 2023
    Last edited: Nov 30, 2023
  2. bisco

    bisco cookie crumbler

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    I can’t see the link, but I picked up a noco from amazon for &30. and it’s great.

    you won’t have any trouble in a hot garage
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    What's your parking situation? What country are you in, and what area of the country?

    For 3~4 months you definitely need "something". Dead-simple is to disconnect the neg cable. It's arguably the optimum approach for long term storage, perhaps coupled with a full charge at the outset. You can also remove the battery from the car, if practical.

    Our situation is we drive once or twice a week, and car's stored in a secure garage with 120 volt AC outlets. Unless the car's getting used on consecutive days I connect the battery to a smart charger, let it run it's charging regimen, and leave it connected till we next use the car. I'm using a CTEK 4.3. Equiv now is CTEK 5 I believe. It's worked well for some years now, battery was installed over 8 years ago, still load testing like new.

    The CTEK chargers typically come with a quick-connect harness you can wire in, makes it more convenient, especially if you're connecting frequently. They also have aligator clips that work fine, just a little more cumbersome. If you're interested in installing a quick connect I can provide more detail, a good under-the-hood location to tap in.

    BTW, Amazon links "behave" better here, if you type some text, select it, choose this button:

    upload_2023-11-30_11-27-25.png

    And paste the amazon link in the field that pops up. This will leave the selected word as a link that is tinted blue. It's a little subtle; I like to also make it bold text.
     
    #3 Mendel Leisk, Nov 30, 2023
    Last edited: Nov 30, 2023
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  4. whataboutbob

    whataboutbob Junior Member

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    Sorry, fixed the link, it's a NOCO GENIUS1, 1A Smart Car Battery Charger, 6V and 12V Automotive Charger. What I am not sure about is the 1A charger if that works with a Prius's battery.
     
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  5. whataboutbob

    whataboutbob Junior Member

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    Sorry, fixed the link, it's a NOCO GENIUS1, 1A Smart Car Battery Charger, 6V and 12V Automotive Charger. What I am not sure about is the 1A charger if that works with a Prius's battery.
     
  6. whataboutbob

    whataboutbob Junior Member

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    Sorry, fixed the Amazon link. That's a great tip about disconnecting the neg cable, I didn't know that's an option but I don't know how to do that, so if you can share a link to a video or something, that'll be awesome. However, I wouldn't mind knowing about a quick connect, please share your process and the actual device. I live in San Jose, CA and can park in a garage. Thanks.
     
    #5 whataboutbob, Nov 30, 2023
    Last edited: Nov 30, 2023
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  7. Mendel Leisk

    Mendel Leisk Senior Member

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    video #23 here shows how to access the 12 volt positive connection on the under-the-hood fuse box. You can connect positive lead there.

    Negative lead you connect to car body. This can be under the head of an existing hold-down bolt, say on some bracket, or at an unused, threaded hole with a suitable bolt.
     
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  8. ASRDogman

    ASRDogman Senior Member

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    Yes, a 1 amp charger will work, it will be slower though, and is better for the battery.
    I think you can unplug the larger white connector in the fuse box under the hood.
    That's where power fromt eh 12v battery comes from. But I'm not sure if it splits
    and goes some where else because I don't remember seeing a white wire on the battery.



     
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  9. bisco

    bisco cookie crumbler

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    1 amp is perfect for maintaining, and the noco senses the type of battery (agm) automatically, and adjusts by itself
     
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  10. ASRDogman

    ASRDogman Senior Member

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    If you just want to "top it off" and keep it fully charged, then the 4amp one is better.
    Then when it's charged it will go into trickle or maintaining mode....
     
    #9 ASRDogman, Dec 1, 2023
    Last edited: Dec 1, 2023
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    I’m using an older version of this, no problems, comes with quick connect cable as well. Pricier.
     
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  12. Mr. F

    Mr. F Active Member

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    For the Genius 1 (and higher models), you do have to press the mode button a few times until it gets to 12 V AGM—it doesn't have a way to automatically detect what chemistry/construction you're working with. But it does default to the mode that was used last time, so if you only ever used it on an AGM battery, you'd never need to cycle through the modes after the first time.

    I have the 5 ampere model that I used to restore a drained battery, and it's worked out pretty well for me so far. However, if I were to purchase one today I would look into the Hulkman series.
     
  13. whataboutbob

    whataboutbob Junior Member

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    Ok I saw the positive terminal in a different location in this video than what's shown in video #23, which one is correct?
     
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  14. whataboutbob

    whataboutbob Junior Member

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    I decided to go with Battery Tender® Junior 12V, 750mA Battery Charger which is less than 1amp but based on reviews, it seem to do the job? Any idea which type of 12V battery, AGM or ?
     
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  15. whataboutbob

    whataboutbob Junior Member

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    I decided to go with Battery Tender® Junior 12V, 750mA Battery Charger which is less than 1amp but based on reviews, it seem to do the job? Any idea which type of 12V battery, AGM or ?
     
  16. Mendel Leisk

    Mendel Leisk Senior Member

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    That's the official under-the-hood connection point for alligator clips. Video #23 is showing where the main 12 volt positive cable feeds in, with a ring connector. For a permanently wired-in quick connector, the latter is a practical place to connect. Space is limited there: I found with the CTEK quick-connect I had to trim off most of the strain-relief plastic shoulder, and bend the wire down, just past the ring connector, or it was too bulky to get the plastic cover back on.

    For replacement 12 volt battery. You want a dimensionally identical AGM (abosrbent glass mesh) battery, with the correct post size/orientation, and compatible vent port. Bear in mind batteries can vent hydrogen, and spill (in a collision), and this battery is in the passenger compartment; that's why fully compatible and vented AGM is required.

    Basically check online, tell them your vehicle, see what they've got that's compatible. Don't rule out dealership parts department, check with them first for sure.
     
    #15 Mendel Leisk, Dec 1, 2023
    Last edited: Dec 1, 2023
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  17. bdc101

    bdc101 Member

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    Our Priuses do indeed have AGM batteries from the factory
     
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  18. whataboutbob

    whataboutbob Junior Member

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    I plan to use the alligator clips connection. My 12V battery was replaced years ago but I assume it uses a AGM battery.
     
  19. whataboutbob

    whataboutbob Junior Member

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  20. bisco

    bisco cookie crumbler

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    who is deltran?

    while oem battery is agm, don't assume it was replaced with one. but a proper maintainer self selects, so i would make sure it has this feature.
    my .75 amp noco self selects battery typem voltage and is protected from cross pollinization. for 30 bucks, it's a no brainer
     
  21. Gardener2010Prius4

    Gardener2010Prius4 Junior Member

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    My situation is similar to yours and I would like to ask all posters on this thread for advice. I was transferred to Chicago from Boise, Idaho January 1, 2023. The new position included a company car so I left my 2010 Prius IV (83,000 miles and Toyota maintenance compliant) in Boise. I returned December 1 to visit relatives (and drive the car) and discovered that I needed to call AAA to jump start the vehicle. I drove the car for several days, then had it serviced (my yearly oil change and service checkup at the Toyota dealership). The service adviser said that the battery that I replaced last year was still good as new and the car was in in excellent shape. The car is parked outside, partial shade/sun, on the side of the house, but not in a covered car port. For the next five years, I'll work in Chicago January-November, then each December, travel to Boise to visit relatives and drive the car while in Boise. How best to "store the car" for 11 months, and drive it for one month. This is a great car and I planned for this to be my primary retirement "town" car (five years from now).