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Thread: Why did my battery go flat ?

  1. #1
    Join Date
    Mar 2019
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    GA
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    Default Why did my battery go flat ?

    '01 xc 70.

    After about 6 hours of sitting yesterday it was too flat to crank the car ( but did light up the dash etc ) and I have some really random thoughts, please tell me which ones are utter BS !

    Recently i replaced the blower motor resistor, with a cheap after market one. Since then I have twice walked outside and found the blower motor running. Googling suggests that this is a feature and shouldn't flatten the battery !

    I noticed that one of the back windows was not all the way up !

    When I go to start the car it says alarm system service required, I have been studiously ignoring this. Is it possible to simply pull a fuse and have no alarm ?

    I set the clock for the first time about two days previously, surely this is not relevant.

    I disconnected the + terminal overnight so that it would start this morning, when I reconnected there was a fairly good contact spark and a whirring noise from somewhere up front, I wasn't paying much attention. That indicated to me that something somewhat power hungry was on.

    Any ideas where to start with this.

    I am quite happy to "simplify" the car, if there are powered systems that aren't strictly necessary ( funny clicking from back wiper, headlight wipers making noises ) I have no issues unplugging stuff and taking out relays / fuses.

  2. #2

    Default

    I suppose the first question might be "How old is the battery"?
    Easiest first step might be to take the car to a car part store that can test for load etc and make sure its OK.

  3. #3
    Join Date
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    Cumbria, UK. Maine USA.
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    The Alarm module could have a bad battery, it will drain the car battery trying to charge it's dud battery up, unplug or replace the module internal battery, or the module itself if it is corroded to heck, or lastly just pull the alarm fuse.
    Last edited by AKAMick; 07-09-2019 at 03:39 PM.
    Current fleet: Countless P.O.S's, Rust buckets, Junk cars,( 50W Oily cesspool Sludge) Stolen and other assorted rubbish Volvo cars, 1928 Jed Clampett Tourer, ( 450K, original rust and decay, 40W Straight Bacon Grease),

  4. #4
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    Quote Originally Posted by AutosDirectFlorida View Post
    I suppose the first question might be "How old is the battery"?
    Easiest first step might be to take the car to a car part store that can test for load etc and make sure its OK.
    Should have mentioned, battery is only about three months old. The "dealer" put it in the day I bought the car.

  5. #5
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    I will try that, although possibly in reverse order of your suggestions based on the least pain in the ass !

    Tks

  6. #6
    Join Date
    Jun 2013
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    Northeast
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    Quote Originally Posted by AKAMick View Post
    The Alarm module could have a bad battery, it will drain the car battery trying to charge it's dud battery up, unplug or replace the module internal battery, or the module itself if it is corroded to heck, or lastly just pull the alarm fuse.
    This was my situation with my 2002 resulting in drained battery. I pulled the fuse and I think I continued to get the message "ALARM SYSTEM SERVICE REQ'D" on startup. So I would clear the message and then be on my way. No more battery drain.
    2007 XC70, 206,000 miles
    2002 V70XC, 130,000 miles, parts car

  7. #7
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    Quote Originally Posted by Xfingers View Post
    This was my situation with my 2002 resulting in drained battery. I pulled the fuse and I think I continued to get the message "ALARM SYSTEM SERVICE REQ'D" on startup. So I would clear the message and then be on my way. No more battery drain.
    Awesome, everyone says these old euro cars are maintenance money pits, so far it's mostly a question of disconnecting superfluous and ridiculously over complicated systems.

  8. #8
    Join Date
    Dec 2010
    Location
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    Quote Originally Posted by BenF View Post
    Awesome, everyone says these old euro cars are maintenance money pits, so far it's mostly a question of disconnecting superfluous and ridiculously over complicated systems.
    New or old the maintenance is the same price, it does not get cheaper as they age, but ignored maintenance compounds itself and costs more in the end, keep up with it or pay.
    Current fleet: Countless P.O.S's, Rust buckets, Junk cars,( 50W Oily cesspool Sludge) Stolen and other assorted rubbish Volvo cars, 1928 Jed Clampett Tourer, ( 450K, original rust and decay, 40W Straight Bacon Grease),

  9. #9
    Join Date
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    Location
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    A large spark when connecting the battery indicates an abnormal load is draining the battery. It should be the tiniest spark (powering the clock, the door fob receiver, and the anti-theft module). Use the audible clue you already found....a stethoscope will help pin it down spatially ( faster than unplugging fuses). It sounds like a solenoid or motor stuck in the "on" position.

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