Float voltage of a Yellow Top Optima?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by 5 Speed, Oct 12, 2017.

  1. 5 Speed

    5 Speed Member

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    What should I be expecting for my Optima Yellow Top? I was thinking that my float voltage should be higher on my new Optima Yellow Top but 12.6 - 12.7V is about the highest after a few weeks of use. I have measured it on my scan gauge and with a 12V meter at the battery.
     
  2. bisco

    bisco cookie crumbler

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    have you charged it?
     
  3. StarCaller

    StarCaller Active Member

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    • Float Charge:
      • 13.2 to 13.8 volts
     
  4. 5 Speed

    5 Speed Member

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    I installed it and it has been in use for the past two weeks but I didn't hook it up to a external charger before using.
     
  5. bisco

    bisco cookie crumbler

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    they don't always come properly charged, and prius is better at maintaining than charging.
    your not far off, but if you charge it and it won't hang around 13v, i would return it.
     
  6. edthefox5

    edthefox5 Senior Member

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    That's correct.

    Prius 12 volt battery charge capacity is a lot different than cars with full size battery's. My other cars live at
    12.9 and higher but the Prius battery lives at 12.6. It was like that with the original battery and it's like that with my new optima. Charge level from the inverter is like 13.8 to 14 volts. The optima failed out of the blue where the oem battery should me signs for days and was able to replace at my leisure. The oem lasted 7 years.
    Which is amazing for Florida.
    My replacement Optima only lasted 3 years even with monthly maintenance charges but I got lucky the autozone I bought it from gave me a new one under warranty. I believe the factory battery is of better quality than the optima and if had to do it again would buy the factory battery.

    But yeah 12.6 is normal as far as I can tell after owning the car 10 years.
     
  7. StarCaller

    StarCaller Active Member

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    "Float voltage is the voltage at which a battery is maintained after being fully charged to maintain that capacity by compensating for self-discharge of the battery."
    btw, my earlier post in this thread is a quote from the optima website..../
     
  8. Sam Spade

    Sam Spade Senior Member

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    You should have.

    But don't you really mean "resting voltage" ?
    "Float voltage" implies that it is being charged at the time.
     
  9. Mendel Leisk

    Mendel Leisk Lapsed Cargo Cultist

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    12.6~1.7 is not bad. I went out and checked ours, it reads 13.0, but it's been plugged into a CTEK 4.3 for a couple of days, and this morning we did a run out to the airport and back. That was about 2 hours back, so I suspect it's high still. If I let it sit and checked again tomorrow morn, I'd expect around 12.75.
     
  10. jzchen

    jzchen Active Member

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    Special batteries, gel or AGM, have slightly different properties than lead acid. They have a special setting for each, lead acid, AGM, or Gel, on my Schumacher chargers that I use. For this reason I would stick with whatever type came with the car in the first place.

    Sounds correct OP....
     
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