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Solar panel to trickle charge the 12V battery?

Discussion in 'Gen 2 Prius Main Forum' started by michalopoulosgk, Oct 8, 2005.

  1. michalopoulosgk

    michalopoulosgk New Member

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    I was gone for 3 weeks last summer with the car left in the garage (indoors). Prior to leaving, I had checked and turned off the "smart keyless entry" feature, checked all lights inside the car, disconnected all charging cables for cellular etc. I came back and the battery was dead. There have been many discussions about the small size of the Prius 12V battery and the fact that it drains easily. It is possible that I forgot something, I suppose, though nothing comes to mind.

    In order to prevent this from happening in the future, I purchased a solar car battery trickle-charger that is built to constantly provide a small charge to the 12V battery and keep it from getting discharged. The charger is supposed to connect to the car battery through the power outlets. There are two of those in the Prius, one under the steering column (on the right) and another inside the storage area under the arm rest. The charger instructions state that ini some cars the power outlets are not operating when the car is shut off and cannot be used for that purpose. My questions:

    1. Are the power outlets of Prius suitable (active, live, etc.) to be connected to a trickle charger and send electricity to the battery when the car is parked and shut off?
    2. If true, is it true for both power outlets?
    3. In addition to the connector through the power outlet, the charger included a cable with pinch-clamps to be connected directly to the battery, if the power outlets are not suitable. Considering that one would have to thread cables between the charger (inside the car) and the battery (under the hood) with all doors locked, this is a kludgey solution, but perhaps worth trying. If so, given that the 12V battery of Prius has only one visible pole for a pinch-clamp, which electrode of the connecting cable I should connect to the 12V battery? The positive or the negative? What should be done with the other electrode?

    Any help and guidance by this very astute group of aficionados would be much appreciated.
     
    #1 michalopoulosgk, Oct 8, 2005
  2. efusco

    efusco Moderator Emeritus
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    No they're not active.

    yup, both are inactive

    The battery is not under the hood, it is in the passenger rear of the hatch area and easily accessible...that's where I have mine connected directly to the battery. The charger can then sit under the large open window of the hatch.

    OR, you can modify the front (dash area) outlet to be active when the car is powered off...it's quite easy to do yourself for pennies or you can buy the kit. Kit and do-it-yourself instructions here:
    http://coastaletech.com/power_outlet_mod.htm
     
    #2 efusco, Oct 8, 2005
  3. Vincent

    Vincent Don't Wait Until Tomorrow

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    michalopoulosgk

    Which Prius do you own?

    Fill out your signature - PLEASE
     
    #3 Vincent, Oct 8, 2005
  4. michalopoulosgk

    michalopoulosgk New Member

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    Thanks Evan! I placed the order through Coastal Tech and will give it a try.

    I have a question though...When I came back and the battery was dead, I jump started the Prius from my wife's car. I followed the instructions of the Prius manual and connected the jumper cable to an outlet (I presume it was the 12V battery outlet) that was in the front of the car, under the hood. Is the outlet under the hood connecting to a battery under the hatch? How can the battery under the hatch be accessed? Is there a diagram somewhere in the manual to point out where is it located?
    Many thanks for all your help!
     
    #4 michalopoulosgk, Oct 8, 2005
  5. efusco

    efusco Moderator Emeritus
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    Yes, the 'outlet' is connected to the battery as an easier access point.

    I don't know of a diagram, but if you go open your hatch and look at the area right behind the tail light you'll see a little access panel on the floor, lift it up and start taking off access panels until you see the battery. It's not difficult and you can't mess anything up.
     
    #5 efusco, Oct 8, 2005
  6. c4

    c4 Active Member

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    If you're thinking of a solar panel, remember that you'll need at least a 5 Watt panel or preferably bigger in order to get any kind of charge at all. Anything smaller than 5W will be totally ineffective as after you subract all the losses and inefficiencies, there's not even enough current left to offset the parasitic drain of the car electronics.

    I would also agree with Evan that the best place to connect the panel is with the clips, directly onto the 12 battery which is in the back of the car.. The terminal under the hood is just a conveniece hookup for jumping..
     
    #6 c4, Oct 8, 2005
  7. michalopoulosgk

    michalopoulosgk New Member

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    Thanks to both of you for the solid advice. I went in the garage and took everything out of the hatch. After about 20 minutes of snarfing I believe that I found the battery, under an access panel directly behind the right (passenger side) tail light of the car. It is covered by a bright red plastic cover that has a big + sign on it. Did not dare to pop it off, I hust lifted it gently and there are two battery electrode type of outlets, unmarked. I intuitely believe that these are the 12V battery outlets.
    Do you happen to know which is the + and the - between the two? How do you connect the solar panel, in that regard?
    I apologize for sounding obtuse, not much experience with any of this.
    Best regards,
    George Michalopoulos
     
    #7 michalopoulosgk, Oct 8, 2005
  8. efusco

    efusco Moderator Emeritus
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    I'm quite sure they're marked, you're just going to need a flashlight (aka Torch for our UK friends) to figure out which is which. My alligator clips just snapped right on.
     
    #8 efusco, Oct 8, 2005
  9. michalopoulosgk

    michalopoulosgk New Member

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    I got the "torch", also found the manual page (300) that describes the battery, and now everything is clear. The manual schematic was very good.
    My solar panel is only 2W, however, so.....maybe back to the drawing board (or to a website with a device of a bigger wattage..)
    Thanks again!
    GKM
     
    #9 michalopoulosgk, Oct 8, 2005
  10. rogerSC

    rogerSC Member

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    I'm sure that you've thought of this, but you'll need skylights in your garage to get much trickling done when you're away and your car is in your garage...

    -Roger
     
    #10 rogerSC, Oct 8, 2005
  11. michalopoulosgk

    michalopoulosgk New Member

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    Hmmm........a new gadget to buy......I can see my wife's reaction.....
    Actually, I am planning to use the solar panel for outdoor parking at the airport. If it loses charge in my garage, I can always jump-start it with the other car.
    Thanks though...
    GKM
     
    #11 michalopoulosgk, Oct 8, 2005
  12. michalopoulosgk

    michalopoulosgk New Member

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    05, silver, package 6!
     
    #12 michalopoulosgk, Oct 8, 2005
  13. michalopoulosgk

    michalopoulosgk New Member

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    One more question:
    If I connect the alligator clips to the battery, cover the other end (to avoid discharge) and leave it there for good, without connecting the solar panel (until I need it, e.g. at the airport), would that cause any harm to the 12V battery?
    Thanks!
    GKM
    (Prius 05, Silver color, Package 6)
     
    #13 michalopoulosgk, Oct 9, 2005
  14. efusco

    efusco Moderator Emeritus
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    Assuming no shorts it shouldn't do any harm, mine's been connected for nearly 2 years, never used, with no harm.
     
    #14 efusco, Oct 9, 2005
  15. Frank Hudon

    Frank Hudon Senior Member

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    if your going to leave it connected indefinatly I would recommend a fuse holder with a 5 amp fuse right at the alligator clip. That way any shorts in the wire would only blow the fuse and not cause a fire.
     
    #15 Frank Hudon, Oct 9, 2005
  16. michalopoulosgk

    michalopoulosgk New Member

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    Many thanks again, to both of you.
    GKM
     
    #16 michalopoulosgk, Oct 9, 2005
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