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2017 Prius prime battery low

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by Dcdoglover, Apr 28, 2021.

  1. Dcdoglover

    Dcdoglover Junior Member

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    2017 Prius Prime
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    Plug-in Advanced
    I took my 2017 Prius prime to the mechanic for the 60,000 miles routine maintenance. The guy told me they did an inspection and the battery was reading low and should be replaced soon. I asked if he meant the big battery in the back and he said no just the engine battery. He quotes me 195 bucks for parts and labor to do this.

    is it typical for the engine battery to need replacing so soon? Anything special I need to know since it’s a hybrid?
     
  2. Tideland Prius

    Tideland Prius Moderator of the North
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    He's talking about the 12V battery (i.e. the regular car battery, like any other car). Seems a bit early to replace but I guess it depends if you've drained your 12V battery before or stressed it in any way.
     
  3. davecook89t

    davecook89t Senior Member

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    Have you ever checked the fluid level in the 12V cells?

    I had gotten used to the sealed AGM battery in our Gen 2 Prius and was not keeping an eye on the on the fluid level under the caps of the regular lead acid battery in our Gen 4 Prius. When I finally checked them 3 years after buying the car, I found them all to be low, so I added distilled water, but I'm afraid some damage may have already occurred. My not-quite-4-year-old battery is now showing signs that it is getting weak, although I have otherwise been very careful about never letting it discharge. (I keep a solar charger on it when the car is not in use). I wonder how many other Gen 4 or Prime owners have also neglected keeping an eye on fluid levels after having gotten used to the sealed batteries in the earlier generation Prii.
     
  4. Dcdoglover

    Dcdoglover Junior Member

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    haha no I’m so not a car person so I’ve never done that before! Had no idea
     
  5. Dcdoglover

    Dcdoglover Junior Member

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    Is there anything I need to do to prevent this? I’ve never left the car on or stressed it just drive it regular. Never left the lights on or anything
     
  6. Salamander_King

    Salamander_King Senior Member

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    With COVID-19 restrictions, many people are not driving enough to charge the 12v battery. If you are currently driving less than 1 hour total/week, you may want to invest in the 12v battery charger/tender to maintain the 12v battery. Your price being quoted is not super high but if you DIY, it can be replaced around ~$100 with a compatible aftermarket 12v battery. That being said, if your current battery is still working, you may not need to replace it for a while. The Prius only need above 12v charge to start the computer, and it doe not require the clod cranking amp to start the engine.
     
    #6 Salamander_King, Apr 29, 2021
    Last edited: Apr 29, 2021
  7. bisco

    bisco cookie crumbler

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    primes suck the life out of the 12v battery because they draw a lot of power when the car is parked.

    before doing anything else, get a second opinion. you can get a free load test at most auto parts stores.
    in the end, 195 bucks installed is a great price.
     
    davecook89t likes this.
  8. dbstoo

    dbstoo Senior Member

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    I bought my car used from a VW dealer. They had let it sit long enough that the 12V went dead. They had a sister dealer (Toyota) recharge it and "certify" that it was good, then put it back on the lot for another month or two. There was no record of this service on the Toyota customer web site. The battery died within 9 months after sitting unused for a week.

    I replaced it with a battery from Autozone for 1/2 the price that the dealer wanted to charge.
     
    Salamander_King likes this.
  9. Tideland Prius

    Tideland Prius Moderator of the North
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    If you’re using the car regularly, no you don’t need to do anything different (especially since you’ve already mentioned things that could drain it).

    The only thing that is Prime-specific is do not leave the car plugged in if it’s not charging. It uses a small amount of energy when the car is plugged in and so the 12V could drain that way.

    Taken care of, the 12V battery can last longer than on a regular car because it’s only used to turn on the computers when you start the car. (Vs a regular car that needs the CCA rating to crank the starter motor).
     
    jerrymildred and Salamander_King like this.
  10. Koolfreak

    Koolfreak Junior Member

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    Two
    My 2 Prius C 2012 (230 000km and 170 000 km) still on their original 12 volts batteries... And I live in North...
     
    Tideland Prius likes this.