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Old 17th August 2019, 14:37   #1
PerciUrwin
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Default Intermittent Flat Battery

Hi All,

Is it just my car or is is that on these R75's, that if the car is left for more than 4 or 5 days , the cars struggles to start or the battery is completely flat.

( I've had the alternator checked by the AA and is fine).

Perhaps they're just power hungry when sitting idle - i.e immobiliser, and other stuff running in the background.

any thoughts on this would be welcome.

Rgds,

John.
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Old 17th August 2019, 14:58   #2
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Quote:
Originally Posted by PerciUrwin View Post
I've had the alternator checked by the AA and is fine
What about the battery itself, have you had it checked?
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Old 17th August 2019, 16:10   #3
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How old is your battery ?
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Old 17th August 2019, 16:48   #4
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My 75 has been parked for a week on 3 occasions...no trouble starting. Battery the likely culprit when described by your good self.
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Old 17th August 2019, 17:03   #5
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John,

Think about how frequently you use the car and the length of your journeys. For example, moving the car on and off the drive or very short trips to the shops doesn't give the alternator enough time to replenish the charge taken by the starter motor.

Car batteries last a long time if they're kept fully charged. The reality is that few are. You may need to invest in a smart maintenance charger which can be left connected.

Simon
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Old 17th August 2019, 20:33   #6
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Is your car fitted with hi-line or does it have a gps CD-rom driver fitted in the boot on the right hand side. I've been having similar issue with me battery, would always have a drained battery, I tried different batteries and still it would drain. I thought it could be the alternator regulator but someone told me to disconnect the gps. When my car ignition was turned off the gps was still drawing power from the battery, I've disconnected it and never had the issue since.

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Old 18th August 2019, 07:13   #7
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Quote:
Originally Posted by Coidy View Post
Is your car fitted with hi-line or does it have a gps CD-rom driver fitted in the boot on the right hand side. I've been having similar issue with me battery, would always have a drained battery, I tried different batteries and still it would drain. I thought it could be the alternator regulator but someone told me to disconnect the gps. When my car ignition was turned off the gps was still drawing power from the battery, I've disconnected it and never had the issue since.

Sent from my SM-G975F using Tapatalk
Had the same with my 75 when I got it. Previous owner had even had a rocker switch fitted to completely cut power to the entire Highline system when car was not being used. I tried leaving this turned on a few times and something in the Highline system drained the battery every time.
Junked the whole Highline system in the end and fitted an Android head unit instead. Much better system and it don't drain battery
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Old 18th August 2019, 08:44   #8
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Quote:
Originally Posted by Coidy View Post
When my car ignition was turned off the gps was still drawing power from the battery, I've disconnected it and never had the issue since.
Quote:
Originally Posted by Bullnose75 View Post
Previous owner had even had a rocker switch fitted to completely cut power to the entire Highline system when car was not being used. I tried leaving this turned on a few times and something in the Highline system drained the battery every time.
John; a word of caution relating to these two posts. The sat. nav. disc drive/computer can indeed drain the battery if it does not complete its shutting down procedure. Successful shut-down is signified by the red LED on the unit extinguishing after about thirty seconds. The unit should not have its power supply removed, either by unplugging it or by disconnecting the car's battery, until this process is complete. Failure to observe this results in the sat. nav. unit being permanently incapable of shutting down and consequently draining the battery. The unit can also fail to switch off if it has suffered rainwater damage.

So there isn't anything intrinsically wrong with the hi-line sat. nav. system. Coidy and Bullnose75 suffered the consequences of previous owners', or their garages', actions.

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Last edited by SD1too; 18th August 2019 at 08:48..
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Old 18th August 2019, 09:41   #9
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As it's not been mentioned so far, check to see if the background illumination isn't still lit on the light switch bezel after the car is locked.

This prevents the BCU entering sleep mode, and instead of a quiescent current of 35 to 40 mA, you end up with a constant current of 2.5 to 2.8 A (2500mA)

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Old 18th August 2019, 10:50   #10
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Both my 75 tourer and ZT-T recently stood for 6 weeks whilst I recovered from a hernia operation, nether where started or charged during the lay up and they both started with no problems when I could drive again ( the 75 is a diesel, the ZT-T has sat-nav etc, both were locked and alarmed for the duration ), Both have batteries that are under three years old.
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