Is a battery tender bad for a battery? | FerrariChat

Is a battery tender bad for a battery?

Discussion in '456/550/575' started by 00 550, Apr 28, 2011.

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  1. 00 550

    00 550 Formula Junior

    Oct 20, 2009
    412
    FL
    Full Name:
    That guy
    #1 00 550, Apr 28, 2011
    I searched the previous posts on this issue, but was curious of any other thoughts on this...Came out of work yesterday and car wouldn't turn over, just "click-click-click" Had sat for about 10 hours while I was at work. I always connect to a CTEK battery tender, every night, when at home, and it always reads a green light when I go out to car in am. Car had only seemd to have slightly less juice at start up for the last 2 days, no other signs of weak charge. Got a jump, and drove home(10 minute drive) no problem. Connect to battery tender and it reads green light like it is fully charged again. Took battery out and replaced under warranty, as I bought it only 9 months ago. It is an Interstate MT-34R. I have not connected new battery to tender in fear of maybe it contributed to the previous battery's early demise. New battery is strong and noticeably has more juice at start up. I guess it is possible that I didn't notice the slow wear down of the previous battery, but why is the tender showing a green light, and is it possible for it to shorten the life of the battery? I know a trickle charger can hurt a battery over the long run, but I thought CTEK tender prevented that
     
  2. 2000 456M

    2000 456M F1 World Champ

    Sep 29, 2007
    12,600
    Portland, OR
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    Allan
    #2 2000 456M, Apr 29, 2011
    I think a pattern of ruining batteries would have shown up by now. (I keep mine on a tender all winter since I drive it very little from November through March). Some think that they may have an adverse effect. I'll let them chime in on their own.
     
  3. maranello72

    maranello72 Formula Junior

    Jul 4, 2009
    348
    Munich, Germany
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    Stefano
    #3 maranello72, Apr 29, 2011
    Battery tenders should actually extend the life of a battery as they prevent lead sulphite from depositing on the electrodes (this happens naturally as the battery discharges).

    It is however important that the tender's voltage never exceeds about 13.8v, below which there is no significant production of gas (oxygen and hydrogen) in the battery.
    Above this voltage, the electrolyte will slowly turn into gas, and in the very long run the battery will begin to dry up and loose performance.

    Check your tender's voltage with a multimeter and make sure that once the green light is on (i.e. trickle charge has begun) it's not exceeding 13.8v!

    Stefano
     
  4. 166&456

    166&456 Formula 3

    Jul 13, 2010
    1,723
    Amsterdam
    #4 166&456, Apr 29, 2011
    I have a few questions for you, to see if you're looking in the right place.

    Why connect a trickle charger every day? I ask this since that is normally only needed if you park the car for a significant amount of time (months rather than weeks).

    The battery was 9 months old, why was it changed in the first place, how old was the previous one and was that one maintained the same way?

    Are you sure the car doesn't have a drain? A drain may be larger than the power the charger puts in.
    A drain can also confuse some trickle chargers, some of them can only tend a battery that is completely stand-alone and not connected to the car.

    Last, perhaps a silly one. Does your garage have a power system that kills the power to the sockets when the lights go out? :D
     
  5. 00 550

    00 550 Formula Junior

    Oct 20, 2009
    412
    FL
    Full Name:
    That guy
    #5 00 550, Apr 29, 2011
    Battery was rePlaced 9 mOths ago trying to chase a few gremlins (actuator light). Have only used the tender since then. So no real experience with it prior to that. I use the tender every day jet because inhad heard it wouldn't hurt the battery and that these cars tend to drain the battery fast when not driven. Thanks for the replies
    -C
     
  6. rmani

    rmani F1 Veteran
    Owner Silver Subscribed

    Nov 1, 2003
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    NJ
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    RMani
    #6 rmani, Apr 29, 2011
    how do i check this?
     
  7. ferraridriver

    ferraridriver F1 Rookie

    Aug 8, 2002
    4,134
    Bay Area Calif.
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    Dave
    #7 ferraridriver, Apr 29, 2011
    You might try unplugging the tender from the wall and let the capacitors discharge before connecting it to the car. I have to do this sometimes or the light just stays green when I know the battery needs charging.
     
  8. dahecht

    dahecht Rookie

    Jun 18, 2008
    24
    #8 dahecht, May 8, 2011
    Make sure your tender is working properly, I had the battery in my 550 explode. Ferrari told me it was caused by a defective charger. I bought a new one and have not any problems and use it all the time
     
  9. maranello72

    maranello72 Formula Junior

    Jul 4, 2009
    348
    Munich, Germany
    Full Name:
    Stefano
    #9 maranello72, May 9, 2011
    Connect the tender, leave it charging overnight, then in the morning check the battery's voltage (any cheap multimeter will do) while the tender is still connected and charging.
    At that point the battery will be 100% charged and the tender should only be trickle charging, i.e. not exceeding 13.8v.

    Stefano
     

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