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Toyota TrueStart Battery Technology and Charging

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Mike_D, May 5, 2024.

  1. Mike_D

    Mike_D New Member

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    Hello all, first time poster! My children's grandfather was a very happy multiple Prius owner, and they were fortunate to have him pass down his used Prius' to them as their first cars to learn how to drive, they love them! As I am the family stuckee for automotive maintenance, I'm trying to come up the learning curve for all things Prius. My first questions are concerning the Toyota TrueStart batteries that are installed. This is what we have:

    2016 Prius Four Touring 5Dr. Sedan
    Toyota TrueStart battery part# 00544-H4052-470
    470 CCA / 74 RC
    Installed 10/2021

    2019 Prius Limited 5Dr. Sedan
    Toyota TrueStart battery part# 00544-H4470-TS
    470 CCA / 74 RC
    Installed 5/2024

    My question is, are these 12-volt batteries traditional Wet Cell/Gel Cell/Flooded? Or are they AGM (absorbed glass mat) technology (where the battery acid inside is not free-flowing but rather is absorbed into fiberglass mats)? We had the new battery installed in the 2019 Prius yesterday at our local AutoNation Toyota dealer, and neither the parts guy or our service rep could answer this question!

    I'd like to put my NOCO genius G3500 3.5 Amp (2-120Ah) smart battery charger on both batteries to make sure they are fully charged, but this charger has two different settings: 12V NORM (14.5V, 3.5A) for Wet Cell/Gel Cell/Flooded, and 12V COLD/AGM (14.8V, 3.5A) for AGM batteries. Not sure which setting to select.

    Anybody know? Any other tips you have to share for maximizing the life of these batteries would also be greatly appreciated! Thank you.
     
    #1 Mike_D, May 5, 2024
    Longinus876 likes this.
  2. bisco

    bisco cookie crumbler

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    treat them as traditional flooded lead acid, they are not agm unless someone replaced the oem with agm, but it would say so on the label. they do have some kind of newer ingredients i think, but does not affect charging.
     
    #2 bisco, May 5, 2024
  3. Mike_D

    Mike_D New Member

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    Thanks bisco. I looked over all of the labels/markings on both batteries, and I see no indication that they are AGM. I'm going to try the 12V NORM setting with the slightly lower charging voltage. Have a great day!
     
    #3 Mike_D, May 5, 2024
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  4. Doug McC

    Doug McC Senior Member

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    They should be lead acid batteries in the 4th generation and FWIW a part number check verified it would fit.
     
    #4 Doug McC, May 5, 2024
  5. Mike_D

    Mike_D New Member

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    Thanks Doug McC for the info! The quotes in your signature are great, so true!
     
    #5 Mike_D, May 5, 2024
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  6. AzWxGuy

    AzWxGuy Weather Guy

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    Do you see a removable cap on each of the six cells? A maintenance-free AGM battery probably wouldn't have those.
     
    #6 AzWxGuy, May 6, 2024
  7. FuelMiser

    FuelMiser Senior Member

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    The 2016 and 2019 are Gen 4 Prius with the 12V battery in the engine bay. These are standard wet cell, not AGM. If they are not driven frequently, they should be kept on a tender to avoid low 12V state and failure to start. In the Prius, the 12V is only needed to boot up the computer, it is never used to crank the engine. Thus, it does not need to be very stout.

    One should never use ACCESSORY MODE, powering the electronics with the 12V, because the battery is quite minimal. Instead, bring the car to READY mode by pressing the brake pedal and the power button if you want to run the radio or other systems while not driving. In READY mode, the big traction battery is powering all the electronics, including charging the 12V circuit.

    If you need to replace the 12V battery, it is a standard H4 or 140R form factor. I have used the H4/140R battery from Walmart with success. It is a perfect fit and was around $160 when I bought it. Here is the link,
    https://www.walmart.com/ip/EverStart-Maxx-Lead-Acid-Automotive-Battery-Group-Size-H4-LN1-140R-12-Volt-480-CCA/1656991582
     
    #7 FuelMiser, May 6, 2024
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  8. Longinus876

    Longinus876 Junior Member

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    AGM (absorb glass mat) is SLA (sealed lead acid) with a little vent hose. It's a VRLA (Valve Regulated Lead Acid) w/ a little tube or the released fumes that might burp out. It's more nonsense to make you nuts.
     
    #8 Longinus876, Oct 30, 2024
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