Optima Digital 400 charger setting for Gen 2 12V battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by app-o-matix, Jan 1, 2021.

  1. app-o-matix

    app-o-matix New Member

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    I want to charge a Toyota branded TrueStart 12V battery with an Optima Digital 400 charger, but I’m unsure of which charge profile to set it to. The two profiles which seems as though they would apply are the following:
    • For quick set automatic selection of Optima Redtop and Bluetop AGM starting batteries or other High Performance starting AGM’s.
    • For quick set automatic selection of Optima Yellowtop and Bluetop AGM deep cycle batteries and/or other High Performance deep cycle AGM’s.
    I’m guessing it’s the second one. If I’m correct, is it because the 12V battery in a Prius is not used to start the engine, but rather to power the electronics?
     
    #1 app-o-matix, Jan 1, 2021
    Last edited: Jan 2, 2021
  2. dolj

    dolj Senior Member

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    Choose the setting that will give you a (max) 4 Amp charge rate or less, which I'm picking will be the second one. You can stretch to 5 Amps or less if that is your only option. You really need to understand what the charger is really doing in each one of its stages, though to make an informed decision.
     
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  3. app-o-matix

    app-o-matix New Member

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    Thanks for the reply. The following image from the charger manual outlines the steps it goes through:

    62450268-ADD7-4280-9F16-39AF42F1A6FC.jpeg
     
  4. dolj

    dolj Senior Member

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    That is pretty genric information and typical of these types of chargers. It is a bit light on details like the voltages and amperage used in each stage.
     
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  5. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Gen 2 owner’s manual stipulates 3.5 amps max If I recall correctly. 4.0 is close though.

    it could be the charger is varying voltage with the various settings? If in doubt be conservative, use setting with lower voltage. If it’s possible to figure out. Googling might help sort that out.
     
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  6. app-o-matix

    app-o-matix New Member

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    (Note: For anyone who gets this far and is confused about the actual charger I am using, I noticed it is incorrectly identified in my original post. It is the Optima Digital 400, not 100. I was able to correct it in the text, but not in the title of the post)

    I located the technical specs on the back of the manual which says: "Charge Mode: Up to 4 amps (Large Batteries), Up to 3 amps (Small Batteries)", small batteries being the among the charger's battery profiles that I didn't include in my original post because they didn't apply to my battery.

    So, it looks like I'm okay to select battery profile #2 in attempting to recharge my battery. Since this is an older spare battery, I really don't have anything to lose, as long as there is nothing unsafe about this process.

    Thanks for the help!!!
     
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  7. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Report you first post (there’s a button, and ask moderators to fix title, if you want.
     
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  8. dolj

    dolj Senior Member

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    Gen 2 Battery has a sticker affixed that states 4.2 Amps max.
     
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  9. app-o-matix

    app-o-matix New Member

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    So, I hooked the battery up to the charger and it immediately had three to four green lights (out of five) of charge level. Came back in a few hours and all five lights were green and the charger was already past the conditioning stage (Stage 4) and on to the maintenance stage (Stage 5).

    My question is whether or not this battery is worth keeping. I ask this because it is a 2013 battery and it must have been out of the car because it had died at some point and my old charger (not as robust as my current one, I don’t think) wasn’t able to revive it sufficiently and it was sitting in the garage for core return at some point. And it had been sitting there for awhile, so the initial three to four green lights kind of surprised me.

    Does being able to fully charge the battery say anything about its ability to hold a charge or to recharge with normal driving? If I were to use it in a car again, would I be risking a dead battery in a short period of time?
     
  10. alftoy

    alftoy Member

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    AGM batteries are capable of being deep discharged. Suggest getting a newer digital tester, will analyze and tell the SOC of the battery, also battery life %/CCA amperage.

    My tester is a Solar Clore Automotive BA5, others are BA6, BA7, BA9....("Online" for $48.61)
     
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  11. Mendel Leisk

    Mendel Leisk Sunday driver DIY’r

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    Have it tested with an electronic load tester, better than internet opinion. Most automotive retailer who are selling batteries have such testers and will test for free. Or DIY the test with something like Solar BA9.
     
    #11 Mendel Leisk, Jan 4, 2021
    Last edited: Jan 4, 2021
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