Reconditioning the 12v aux battery

Discussion in 'Gen 2 Prius Technical Discussion' started by sclieu, Sep 25, 2010.

  1. sclieu

    sclieu Junior Member

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    I've seen threads about replacing the aux battery, but none about whether this battery can be reconditioned. i'm 100% sure mine is bad as I have a 90+ mile daily commute and the battery has problems even after driving all this distance. The battery meter shows average 50% charged (not sure if this is the main battery or aux that I'm looking at), but yet it has trouble starting the car this past week, and finally went completely dead. I could not even open the door, and trunk...

    Luckily, I went to my favorite place which sells new/used batteries, and they had a similar battery, and am working fine now. They said it is almost new (looked like it), but that it was not from a prius. It had a similar size and the plug for the gas vent, etc.., but they didn't exactly fit the same. Because the battery post were so close together, putting on the connectors and it was in the way of the small trunk compartment panel closing.

    Car is working great now, but I can't close that compartment, and will need to buy a little hose to properly vent out gas.

    I was hoping to get the original battery reconditioned and put back in. I think recharging it will not work, as the prius should automatically recharge it but it still fails.

    Anyone know if this is possible, and if so, have any local places to do it? I'm in the Los Angeles/OC/Inland Empire area.

    Thanks!
     
  2. Michael33

    Michael33 Member

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    Sometimes a deep cycle battery can be revived, but forget about "reconditioning" it to near new condition. Since this is apparently a lead-acid battery (it needs a vent) you should replace it with one that fits exactly and is the same type. I seem to remember reading here that Optima batteries makes one that fits exactly.
     
  3. ursle

    ursle Gas miser

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    Not to sound harsh or cynical, there are lots of threads about the 12 volt batteries in the gen 2 cars, yes it's a deep cycle but it happens to have an extremely short life. Optima does make a battery that physically fits, doesn't need venting (gell battery) but needs a conversion kit for the electrical connection, all very available.
    When you have a strong battery the car doesn't have to run the ICE to charge it as often as a battery that's constantly in a state of discharge so your electric car is actually electric...
     
  4. jayman

    jayman Senior Member

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    I had problems the very first winter with my Prius. A combination of a 15 minute commute, winter so headlights on, -40 temps so Max Heat and constant electric defrost, all managed to drag the 12 vdc battery down.

    It got to the point when I would power up in the morning, the auto headlights would turn on to a sickly yellow glow, and almost go out before the main relay closed the the Traction battery supplied the circuit.

    If you catch this problem in time, you won't damage the battery. I had to go away for a month on business, and at the time I owned a condo with heated underground parking. I pulled the battery, put it in my suite, and hooked it up to a VDC Battery Minder

    BatteryMINDer® Plus 12 Volt 1.33 Amp Charger-Maintainer-Conditioner (Desulfator) | All | Battery Chargers by BatteryMINDers.com

    That cured the problem. When I powered up the first time, the auto headlights barely flickered. So I wired in the charge harness and got into the habit of leaving the Battery Minder plugged in overnight.

    As I rarely have to drive now, I also leave my FJ plugged into a Battery Minder 24x7.

    I would suggest just getting a new battery. Make sure to properly charge the new battery before installing. The Prius isn't very well suited to properly charging a 12 vdc battery at 50% charge, and the new battery won't last very long
     
  5. richard schumacher

    richard schumacher shortbus driver

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    What they wrote. If you use a "reconditioned" battery you're just setting yourself up to get stranded somewhere.
     
  6. sclieu

    sclieu Junior Member

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    thx guys. Lots of good responses. For now, the battery I have works fine, and seems to keep it's charge. I'll invest in a new battery soon just in case. I'll look into the optima gell battery, but with the battery and kit, I'll be out over $150!! I guess that's more than some have posted for a dealer battery, but the optima battery is a lot better.

    I'm really surprised there's no business out there that would take a used battery and 'rebuild/recondition' it. I would think doing that would be well under $100 and they can certainly charge that much, if not more...or is it totally different and more costly to do this for this type of battery, versus acid?
     
  7. jdenenberg

    jdenenberg EE Professor

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    Did you notice the Battery Minder reference in an earlier response? It is a $60 device that will recondition a 12v battery as long as it is not too far gone. There is no need for a service given an inexpensive solution already exists.

    JeffD
     
  8. uart

    uart Senior Member

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    Hi sclieu, you should measure the voltage of your battery in the morning after it's been sitting overnight (before you turn on the car). If it's fairly high like about 12.6 to 12.8 volts then you know you've got a good one. If it's fairly low like about 12.0 to 12.2 volts then you probably got ripped off.

    Follow the instructions in the first post here : Entering Maintenance Mode (aka 12V Battery Check) without Switching Headlights ON/OFF | PriusChat but with the corrections made below.

    - Do this test after you have driven the car for at least 30 minutes. This will give the battery a chance to be fully charged.
    - Do this test after the car has been off for at least several hours, preferably in the morning before starting the car for the day. Yes it's a good idea for the car to have been driven a lot in the days before the test, so as to give the battery a better chance of being charged, but the test better weeds out weak batteries if it's been left off for at least several hours before the test.

    -Push in the power button. (if not already on)
    - With your foot off the brake pedal push the power button. Don't go to ready mode.
     
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