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Thread: Replacing a battery

  1. #1
    Z8 Novice
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    Replacing a battery

    My battery has died after about 4 years. It was on a battery tender and still failed. I want to change the battery myself but don't want to create issues. The last time my battery completely died the head unit died as a result. So my question: any issues or suggestions on replacing the battery myself. Based on what I read on other posts, I was going to look into the battery available from Batteries Plus. During replacement I planned to leave the car hooked to the charger while swapping. Does this sound like the best process? I've also read discussions about registering the battery. However, with this battery being a like replacement is that necessary? Thanks
    Terry

  2. #2
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    Quote Originally Posted by THowell View Post
    My battery has died after about 4 years. It was on a battery tender and still failed. I want to change the battery myself but don't want to create issues. The last time my battery completely died the head unit died as a result. So my question: any issues or suggestions on replacing the battery myself. Based on what I read on other posts, I was going to look into the battery available from Batteries Plus. During replacement I planned to leave the car hooked to the charger while swapping. Does this sound like the best process? I've also read discussions about registering the battery. However, with this battery being a like replacement is that necessary? Thanks
    Terry
    Yes keep 12 volt power on the system to avoid a power jump in voltage. You can also turn the lights on.

    Z8Ros

  3. #3
    Carter Carter Rise's Avatar
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    My battery seems dead, so I am going to throw a new one in today. I had assumed our cars are old enough where I can just replace the battery without worrying about the system needing to "learn" anything or creating other problems, but this post has given pause. What does "keep 12 volt power on the system" mean - is that just keeping the trickle charger plugged in?

  4. #4
    Carter - I have had mine replaced twice (second time under warranty) with out any life support during the switch with zero ill effects or programming needs afterwards. Had the battery replaced at Batteries plus - replacement was about $150 (no charge for labor). This was 5 or more years ago and it has performed great.

    https://www.batteriesplus.com/replac...9extj/sli49h8m
    Skip Hammerman

    2002 BMW Z8 - Meisterschaft GT, PP installed, CDV delete
    2013 BMW X3
    2015 Porsche 911 Targa 4S

  5. #5
    Team Z8 Satch's Avatar
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    Well, you'll have to re-set the clock....

  6. #6
    Quote Originally Posted by Satch View Post
    Well, you'll have to re-set the clock....
    Well yes... And you might have to reset the window down with one touch memory function.
    Skip Hammerman

    2002 BMW Z8 - Meisterschaft GT, PP installed, CDV delete
    2013 BMW X3
    2015 Porsche 911 Targa 4S

  7. #7
    Carter Carter Rise's Avatar
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    Thanks. All went well. On the road again.

  8. #8
    DSC Off bclaude's Avatar
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    I have a battery isolator on the negative post of the battery. When the car goes into winter storage, I open the isolator to eliminate potential slow discharge of the battery (which I keep on a CTek charger). This effectively meant that the car receives zero power during all the winter months. When comes time to drive the car in the spring I close the isolator, remove the battery maintainer and the car fires right up. As Satch said, all I have to do is set the time. On that basis I think there is zero need to keep the car powered for the few minutes it has no battery.
    ------------------------
    Regards,
    Bruno

    2003 Stratus/Crema

  9. #9
    Z8 Novice
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    I am curious to know how you did the battery isolator. There isn't much room in the battery compartment.

  10. #10
    DSC Off bclaude's Avatar
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    See the photos, they show the isolator on the negative battery post and the CTek connector for the battery maintainer. Off season I keep the isolator open and the battery is maintained by the CTek charger. I also use the isolator as a crude anti theft device when the car is left parked in a questionable location. The Isolator can be purchased in any auto parts place or on Amazon.https://www.amazon.com/Post-Battery-...CCQT9S2ZJ5HK8N
       
    ------------------------
    Regards,
    Bruno

    2003 Stratus/Crema

  11. #11
    Z8 Novice
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    I didn't think there was enough clearance above the battery and below the floor cover to fit one of these. I will check when I get home. Thanks for posting the pics and the amazon link.

  12. #12
    Team Z8
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    I hadn't installed one of those for the same reason...it looks likes the floor board of the trunk would be resting on that knob.

  13. #13
    DSC Off bclaude's Avatar
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    The top of the black knob is essentially at the same level as the rail the floor board rests on. Exact measurements are hard to make because the area is all carpeted. I am positive that the floor board closes as it used to, there is no difference to the naked eye between the left side and the right side where the isolator resides. I canít exclude that the floor board touches the top of the knob but I have used it like that for 4 years and there is not mark on the floor board to indicate any issue. Worse case scenario, if there is contact, there never will be any serious load on that floorboard that would cause any harm. Sure hasnít been an issue on my car and I love the way it protects my battery from discharging. I have used a combination of this isolator and a CTek on another car I drove occasionally and kept the same battery for 15 years.
    ------------------------
    Regards,
    Bruno

    2003 Stratus/Crema

  14. #14
    Bruno, the isolator is a good idea. I too disconnect the battery for long storage, with no ill effects. However, getting the car going again is a bit of a process without power: manually unlock the drivers door, unlock the compartment behind the passenger seat, remove the fuse box cover, pull the manual trunk release ring, finally reconnect the battery. Is that what you do as well?
    Tyler
    60658 Silver
    Los Angeles

  15. #15
    DSC Off bclaude's Avatar
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    Hi Tyler, you bring a very good point, if you keep the doors and trunk lid locked when the battery is disconnected then yes you need to manually unlock the driver door and pull a ring inside the storage compartment behind the passenger seat to manually unlock the trunk so that you can reach the battery to reconnect it. The ring is hidden under the fuse box. For that reason, it is VERY important to move the passenger seat forward and tilt the back rest vertical BEFORE you disconnect the battery. If the passenger seat is left all the way back, it may be impossible to reach the storage compartment and the string inside it. Since the seats are not powered, they can't be moved out of the way and with the trunk locked you can't reconnect the battery to get power... This happened to me once and I had to use jumper cables connected to the terminals under the hood the way you jump start a car to power the car/seats so that I could move the passenger seat forward and manually unlock the trunk, thank god! Anyone planning on disconnecting the battery one way or the other, don't forget to first move the passenger seat forward. When my car is in storage, I leave the trunk lid cracked open to preserve the seal and therefore this is no longer an issue for me. I any event I still make sure I move the passenger seat forward just in case the trunk lid gets latched accidentally.
    ------------------------
    Regards,
    Bruno

    2003 Stratus/Crema

  16. #16
    Team Z8 Satch's Avatar
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    I have now used the Optima chargers/maintainers on Buffy and Nancy Drew for two years now, batteries connected, trunk lids ajar, with no issues whatsoever.