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Battery Maintainer for 12v Question

Discussion in 'Gen 2 Prius Technical Discussion' started by PriusGuy32, Nov 10, 2012.

  1. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

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    I just bought a 1.25amp Schumacher battery maintainer for my 12v battery for a song and dance at Advance Auto Parts.

    I chose not to hook it up under the hood because the wiring harness was real short and I'd have to open the hood each time if I wanted to use it. I decided to hook it up direct to the battery in the trunk. Of course, this is using the semi-permanent attached ring harness they provide with the kit.

    Is it ok having the neg- end of the battery maintainer wire on the Prius negative battery cable end where it attaches to the body in the trunk? I couldnt easily access the nut on the end of the battery cable that was attached to the lug on the 12v battery.

    Is that ok?
     
  2. maestro8

    maestro8 Nouveau Member

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    Relax, you're fine. A battery maintainer doesn't push a lot of current, so it doesn't need a direct battery connection... in fact, some battery maintainers push their current through the accessory socket in the dash.
     
  3. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

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    Ok cool. Thanks for reassuring me.

    I just wanted a tender/maintainer I can run overnight every now and then to keep the battery resting volts at its best. I have a new (1 month old) Optima 12v but I figure the more volts the merrier, right :D
     
  4. maestro8

    maestro8 Nouveau Member

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    Not necessarily. Charging a battery causes it to heat up internally... and with too much heat, the electrolyte will boil off, reducing the battery's capacity. Your smart charger has circuitry to prevent this, but you'll still be adding heat to the battery every time you charge it.

    Automotive battery maintainers are intended for use with vehicles that see little use. If you drive your Prius regularly, the generators will create all the power needed to keep the battery at optimal voltage. If your new battery is draining quickly, there is likely something wrong with your car, and the maintainer will only mask the symptom.
     
  5. dhancock

    dhancock 2 Prius Family

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    I have that particular maintainer and can assure you that it does not heat up the battery (it shuts down charging once a full charge is obtained. Keep in mind that regular use of the car also adds the same heat to the battery.

    But I do agree that there is no real point in regular use of the maintainer. I only use it when we are going to leave the car idle for more than a week.

    P.S. I also have mine connected directly to the battery, and I also have a Optima battery.
     
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  6. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

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    For the price I couldnt go wrong. Plus I can use it on the lawn tractor for the winter too. Im going to use it on the Prius here and there just to get my moneys worth out of it :D
     
  7. Britprius

    Britprius Senior Member

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    The Optima is actually a valve regulated sealed lead acid battery that will recombine the gasses produced when being charged to produce water so that the battery does not dry out.

    This drying out only happens at high charge rates (over 10amps) when the battery warms up this is why Optima say to monitor the battery temperature when charging at over 10amps and to stop charging if it goes above a certain level.