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Prime 12V battery upgrade. Increase size, reserve, Ah, etc.

Discussion in 'Prime Accessories and Modifications' started by OptimalPrime, Dec 28, 2020.

?
  1. Yes, more than twice.

    5 vote(s)
    21.7%
  2. Yes, twice

    1 vote(s)
    4.3%
  3. Yes, once

    0 vote(s)
    0.0%
  4. No.

    17 vote(s)
    73.9%
  5. I don't recall. Could I be indicted if I did recall such a thing?

    0 vote(s)
    0.0%
  6. Define battery failure while I text my attorney.

    0 vote(s)
    0.0%
  1. Jon in Maine

    Jon in Maine Junior Member

    Joined:
    Jan 2, 2023
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    Location:
    04258
    Vehicle:
    2024 Prius Prime
    Model:
    Prime Plus
    After reading posts here, Ithought I could fit a group 47 battery in my 2017 Prime. I had to cut both ends from the battery tray and even then there wasn't much room. The front end is about 1/8 inch from sheet metal. I did not have to relocate any cables.
     
  2. OptimalPrime

    OptimalPrime Member

    Joined:
    Sep 17, 2017
    107
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    Location:
    Keene/Nashua
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    Sorry for the very late reply.

    I am just finishing up the tread life of the 205/70 soon, and have already bought 205/65 again to replace them, though I cheaped out this time and got cheaper tires to experiment with. I got a pair of Continental VikingContact7 and a pair of General Altimax Arctic to play with, the first time in a long time I didn't get a matched set of 4. But I paid an average of $90 per tire on Amazon and eBay (new, mfr stickered tires) by grabbing or two as available cheaply.

    The 205/70 were a successful experiment to see what is the largest tire the 17-22 Prime can use without a lift kit. But I did buy my set of them cheap and used only one winter, from a CR-V owner moving from Maine to San Diego. So they already had their diameter reduced by maybe 1/8 inch, and they did rub the wheel well one time when I pulled g's in a road dip. For that reason, I just can't recommend them to the general public, though I can verify that they did work for me.

    I got them because I take my Prime into some surprisingly serious off-roading situations, believe it or not. Two of my travel interests are visiting sites of remote airplane crashes and alleged UFO incidents, mostly out in the 4-corners states.

    But the handling is noticeably more twitchy and less stable than the 205/65, which are superior to the stock size in my experience. The 205/65 Michelins are just an incredible tire, and in summer will make you forget they're a snow tire. Note that I run them at 50psi myself, and love the stiffer handling that causes, plus the additiional ground clearance.
     
  3. OptimalPrime

    OptimalPrime Member

    Joined:
    Sep 17, 2017
    107
    74
    0
    Location:
    Keene/Nashua
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    Sorry for the very late reply.

    I am just finishing up the tread life of the 205/70 soon, and have already bought 205/65 again to replace them, though I cheaped out this time and got cheaper tires to experiment with. I got a pair of Continental VikingContact7 and a pair of General Altimax Arctic to play with, the first time in a long time I didn't get a matched set of 4. But I paid an average of $90 per tire on Amazon and eBay (new, mfr stickered tires) by grabbing or two as available cheaply.

    The 205/70 were a successful experiment to see what is the largest tire the 17-22 Prime can use without a lift kit. But I did buy my set of them cheap and used only one winter, from a CR-V owner moving from Maine to San Diego. So they already had their diameter reduced by maybe 1/8 inch, and they did rub the wheel well one time when I pulled g's in a road dip. For that reason, I just can't recommend them to the general public, though I can verify that they did work for me.

    I got them because I take my Prime into some surprisingly serious off-roading situations, believe it or not. Two of my travel interests are visiting sites of remote airplane crashes and alleged UFO incidents, mostly out in the 4-corners states.

    But the handling is noticeably more twitchy and less stable than the 205/65, which are superior to the stock size in my experience. The 205/65 Michelins are just an incredible tire, and in summer will make you forget they're a snow tire. Note that I run them at 50psi myself, and love the stiffer handling that causes, plus the additional ground clearance.

    My current plan is to do a modest 30mm lift to help the 205/65. But I may sneak in one last trip out west on the 205/70, which should get the tread down to the replacement bars at 2/32 of tread. Whether I'll do the lift before or after that, I'm not sure.
     
  4. OptimalPrime

    OptimalPrime Member

    Joined:
    Sep 17, 2017
    107
    74
    0
    Location:
    Keene/Nashua
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    In 2021, two local O'Reilly's stores couldn't get the ACDelco battery into stock, so I just bought a Golabs R300 LiFePO4 power station and left my car battery alone.

    But right now I'm looking at this winter being the 7th winter for my original battery, so I'm thinking it might be time to finally do the mod. Sorry you had to cut the battery tray to fit the Group 47, but I did characterize that battery length to be between ambitious and aggressive. Do you have an exact measurement of how long your new battery is (and is it the same top and bottom, or does it have protrusions) and could you tell me what make/model of battery it is?

    I'm going to take another look at what types/sizes are currently available, and also check whether O'Reilly's or anywhere else cheap, can get the particular ACDelco I was planning to get.
     
  5. vvillovv

    vvillovv Senior Member

    Joined:
    Mar 19, 2013
    3,536
    1,245
    1
    Location:
    NY
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Plus
    I replaced our Primes 12 volt spring 2023 with an OEM Truestart from a dealers parts counter.
    I'm one of the now 17 survey responders that hasn't run the 12 volt dead, but I have seen low 12.2 volts at times taking readings using a multi meter and leaving the hood unlatched for a few hours to not wake up the Primes sensors by opening a door to unlatch the hood.
    I took readings of each cell of the battery and the cell connected to the positive post was shorted. I marked the cell cap and let the battery sit for a week. A week later I tested each cell again and this time the cell attached to the negative post was shorted. One of these days I hope to have a better understanding of Batteries. ;)
     
  6. caymandiver75

    caymandiver75 Member

    Joined:
    Jan 5, 2011
    189
    97
    0
    Location:
    Northern VA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    Just had to replace my 12v battery in my 2019 Prime with just 36,000mi. Of course the battery died on a Sunday and NO Toyota part centers are open so I checked with my local Lexus dealership and they had some. 84month warranty! Price was $225.
     

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  7. sylvaing

    sylvaing Active Member

    Joined:
    Jul 15, 2023
    852
    360
    0
    Location:
    Canada
    Vehicle:
    2017 Prius Prime
    Model:
    Plug-in Base
    You seem to have a clean engine bay for a 4 years old car :)
     
  8. caymandiver75

    caymandiver75 Member

    Joined:
    Jan 5, 2011
    189
    97
    0
    Location:
    Northern VA
    Vehicle:
    2019 Prius Prime
    Model:
    Plug-in Advanced
    Yeah it stays pretty clean. Garage kept and run most of the time on battery only. Notice when running ICE the engine will accumulate dust more than EV mode.
     
    vvillovv and sylvaing like this.