Battery Tender Short | FerrariChat

Battery Tender Short

Discussion in '348/355' started by jim chapman, Apr 3, 2020.

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  1. jim chapman

    jim chapman Rookie

    Sep 25, 2017
    2
    New Forest UK
    Full Name:
    Jim Chapman
    Hi there. 355 GTS 1996

    Well a warning to others re Battery tender condition.. My Optimate has done many good years plugged into the cigar socket and the battery is now 8 years old and fresh as a daisy BUT this week i noticed the wires coming out of the unit has frayed and shorted out. This had turned the corresponding 10A fuse molten in the car floor fuse unit. When I disconnected the charger and replaced the fuse there was a nasty smell of burning before the fuse went again. When I took the lighter assembly out the wires underneath were melted together and horror the two associated wires in the wiring harness tracking up through the centre console also looks melted and fused .

    I assume what happened is the tender unit shorted far enough away on its long lead for the car battery to heat the wiring harness up for a while without taking out the fuse....Check your Tenders!!!

    Back to my immediate problem .How hard is it to get enough off the centre console to be able to follow the harness back to the fuse box.? I'm hoping there is no damage on the other side of the fuse itself?

    Any pointers gratefully received.
     
    Qavion likes this.
  2. emac

    emac Formula Junior
    Silver Subscribed

    Sep 14, 2014
    851
    upstate SC
    Full Name:
    ernest
    Sorry to hear that! I have always used Deltran tenders with a hardwired/fused connector to the battery. I have had a couple of the tenders die over the years, but never an issue like you have. I have been very pleased with Deltran and have used them for at least 20 years on all my stuff.
     
  3. Meister

    Meister F1 Veteran
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    Apr 27, 2001
    5,516
    Duluth, MN
    Full Name:
    The Meister
    I have used tenders on many cars for may years for winter storage here in the midwest. Typically +/-6 months. I know people routinely use tenders that plug into the cigarette lighter and places like Griots like to push these fro owners who don't like to get their hands dirty. I however am skeptical about the cigarette lighter chargers. I have no direct experience with them so the skepticism comes simply from the idea/feeling that the wiring connected to the cigarette lighter is not sufficient for regular uses as a battery tending location. Again no physical or mechanical evidence specifically so I may be wrong but the whole notion of using that location does not register with me. Tending a battery creates heat and heat is what melts wiring insulation and connections.
     
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  4. emac

    emac Formula Junior
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    Sep 14, 2014
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    upstate SC
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    ernest
    I agree, lighter chargers would not be my choice for adding a tender.
     
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  5. Qavion

    Qavion F1 World Champ
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    Feb 20, 2015
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    Sydney
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    Ian Riddell
    #5 Qavion, Apr 3, 2020
    Last edited: Apr 3, 2020
    Ugh... what a nightmare. I only hope your relay panel internals haven't melted. I don't understand why the fuse didn't protect the wiring.

    The hard part of following (or replacing) may be the section under the gear lever. I can't say I've removed that section, but I have removed all the other sections..

    Anyway, with the ash tray removed, this will allow you to remove all the console control panels. Forward of the gear lever is the "saddle". That is held in by about 4 or 5 screws, but to get better access to the lower left forward screw (on RHD cars), it's best to remove the passenger footrest completely (2 clips and 2 bolts). The bolt/s at the top centre of the saddle are a bit of a puzzle. I'm never sure which ones to remove. It's probably best to take photos as you remove them.

    You will probably need to get behind the relay panel (behind the footrest). The relay panel is basically held in with one bolt (the panel is secured with one bolt and two locating pins (slide the panel outboard to disengage the pins. The panel will then fold down and you can inspect the wiring going to the back of the relay panel. You may need to remove the top row of relays to help the panel clear the upper bracket. Also put some rags on the black boxes underneath the relay panel to protect them from scratching.
    Unfortunately, checking the internals of the relay panel may prove a little harder, but it can be done. You may have to grind down some plastic welds to get inside. Note that the connectors on the relay panel can be pretty tight.

    The red-black (power wire) will be the easiest to follow. I can't imagine how difficult it will be to follow the earth wire. It has lots of splices and literally goes everywhere.
    The red-black wire only has one splice (it also provides power to the Parking Light switch). The red-black wire goes into the relay panel on pin 6 of plug J.

    Here's the schematic (I assume you have a 2.7 car?):

    Mirrors/Doorlocks/etc Wiring Diagram

    And here's a diagram showing the location of plug J (with the relay panel folded down from the top).

    Image Unavailable, Please Login


    The wiring harnesses in the F355 can get pretty thick and will be covered with old, gooey "Tesa" cloth tape. You will probably have to buy some new tape. The car will look a lot better with new tape. I would buy a can of Scotch 700 adhesive remover to remove the black gum on the wiring. It works really well. You'll need lots of rags. Make sure you have plenty of airflow through the car when using the Scotch 700.

    Let us know if you run into any difficulties.

    Cheers.
    Ian.
     
  6. Qavion

    Qavion F1 World Champ
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    Feb 20, 2015
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    #6 Qavion, Apr 3, 2020
    Last edited: Apr 3, 2020
    Sorry, I meant following or replacing the wiring.

    I tried to find a picture of the rear of the relay panel, but couldn't find any of plug J. Anyway, my car is a 5.2, so will be somewhat different.

    Here's a front shot of the relay panel on my RHD car with some key details

    Image Unavailable, Please Login

    Note the location of one of the saddle (forward centre carpeted section) screws. It's well-hidden and you may bend or break something if you forget to remove it.

    I'm kind of embarrassed to show that photo. It was taken prior to me cleaning everything and retaping the wiring :oops:
     
  7. yelcab

    yelcab F1 World Champ
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    Nov 29, 2001
    12,661
    San Carlos, CA
    Full Name:
    Mitchell Le
    It's not the end of the world.
    You take the seats out.
    Remove the gear shift knob and plate.
    Remove the ash tray, and window switches
    Remove the mirror switch
    Remove the buttons bezel right of the gear shift rod
    Remove the buttons and bezel front of the gearshift knob.
    Lift out the center panel,
    Remove the front piece of the center panel

    All through these steps you have to find the screws hidden or visible, but they are all there. Mark all your wires before disconnecting from switches and bezels. You will never remember without notes or pictures.
     
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  8. Qavion

    Qavion F1 World Champ
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    Feb 20, 2015
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    Jim, let me know if you do forget. I can usually sort out the wiring with my coloured wiring diagrams. The toggle switches in front of the gearstick are easy to mix up. Note that RHD and LHD switch positions are reversed/mirrored. Also note that the bezel which holds them in can be quite fragile, but they are available from various sources. Ricambi USA advertised them a few months ago.
     
  9. jim chapman

    jim chapman Rookie

    Sep 25, 2017
    2
    New Forest UK
    Full Name:
    Jim Chapman
    Many thanks to you all. I can put the problem in context now
     
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  10. flying butress

    Oct 9, 2018
    35
    Full Name:
    Robin Kohn
    Next time try what I did. Wire a fused float charger directly from the frunck to the battery. If the charger shorts, and the fuse does not open, you only loose a foot of wire. Assuming that the whole thing does not go up in flames.
     

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