Did I do something wrong....? by oldfart

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Rover 75, 04 plate diesel saloon BMW 2.0L engine.

Day 1. Mobile Air Con guy turns up, gasses up aircon. Air con works, then cuts out. Guy tells me its because its overheated, because the Rad Fan isnt turning. He tells me 90% of the time its either the fan or the 100W gold resistor burnt out.

Day 2. Have obtained working fan and new gold resistor, takes 1 hour to figure out how to remove enough of the front to get to it all. In the process, i disconnect the passenger fog light/indicator cluster and the passenger headlight cluster

Day 3. Determine the fan is ok, but the resistor is open circuit, replace it, reassemble. Works when ignition turned on and demist buttion pressed, as it should.

Reassemble front of car. Go to start engine to allow it to idle to ensure correct fan and air con function....nothing. Click click click. Turn lights on, turn windscreen wipers on, try and start car, everything dims and slows slightly. Inconclusive. CAN (Bus Controller Area Network)/OBD (On Board Diagnostics) reader reports nothing wrong. Mate has super duper battery diagnostic device, made by those of Nipponese ethnicity, marvellous device, it determines Battery has suddenly kicked the bucket, it is no more, it is an ex battery.

Replace battery, starts ok, charging ok. Still ok today, a week later. Solved.

Now was this coincidence the battery died, or did I cause the battery to flatten somehow? Nothing was left on, no lights, or anything in the car. Just seems a bit weird it died suddenly, and after fiddling with the car, and leaving lighting plugs unplugged for two days.

Or am I being paranoid?

Posted 21 Apr 2018, 10:34 #1 

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oldfart wrote:Or am I being paranoid?

Possibly.... but probably nothing to do with the car or battery. :lol: :lol:
Batteries can just fail - I've had a couple do that for no reason.

Posted 21 Apr 2018, 12:16 #2 

Im not paranoid. I have mononoia - i think only one person is out to get me.

Srsly. In the past, u can tell when a battery is failing, the car gets harder and harder to start, and if u turn on the lights and wipers, and crank it, the lights will dim and the washers stop or stall. This did neither. It went from good to dead in 48 hours, just sitting their.

Posted 21 Apr 2018, 18:55 #3 

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As I said, I have had a couple of batteries fail for no apparent reason. Parked my diesel 75 tourer up at work and then popped out to move the car a couple of hours later and nothing, dead battery. Earlier car had started without any issues, battery was probably 4 years old just gave up in the space of a couple of hours. Put it on charge at work, having tested the fluids and wouldn't take a charge, it had given up.

When we had a 200 coupe, my wife came back from work and parked up and in the morning battery was dead. Charged it up and it lasted another day before giving up. Put a new battery on it and it was still working 6 months later when we sold it.

I do think that if they get a cell issue (and it only needs to be on 1 cell) then they can just fail. It's all to do with the chemistry of the battery - or it could just be magic :)

Posted 22 Apr 2018, 07:56 #4 

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I have noticed that modern batteries seem to fail with very little notice, although they do seem more long lived than in the past. Batteries from the sixties, seventies and eighties seemed to start a long slow decline from near new.

Posted 22 Apr 2018, 08:57 #5 

Yes, thats the pont. Ive not changed a battery in a car for years, and as Bernard says, in the old days you could see the fail coming - it would get harder to start, it wouldnt turn over as fast when starting, couple of times it'd go flat after driving round in the cold with everything turned on...

Like you say, rather than a gentle curve downwards they now just drop off a cliff edge within hours.

The other thing is the way the onboard computer now complains when you do anything, and disconnecting the battery requires nerves of steel, you just dont know WHAT is going to happen when you power back up. In the old days the worst that could happen was you had to reenter the radio code.

40 years at the practical end of IT taught me Occams Razor - the simplest solution is the best, the simplests explanation is the most likely. Look at the old Mk 2 Sierras, for example, back in the 80's - they had the old reliable, simple, 2.0L Pinto engine, you could fix anything on them with literally and handful of tools from Halfords. The greatest tribute o the fixability of the Sierra was when my mates girlfriend broke down at a motorway services in his Sierra, he got her to change the head gasket with the tools in the boot, talking her thru it over the phone, she got home ok. She was an amazing girl, but it was such a simple car to fix.

You could set the points timing by ear - you just found the two extreme points rotating the distributor where it started to cough, took it back to the middle point then three degrees before TDC was about 1/8" left rotation from that point. You just listened to the engine, they were never too fussy.

Theres alomost nothing on a modern car you can fiddle with, nothing to adjust, unless you have a laptop plugged into it, and the right software.

Posted 22 Apr 2018, 09:29 #6 

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You'll be lucky to get more than 5 years from even a quality modern battery, so when they fail, just buy another one and move on! ;)

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Posted 22 Apr 2018, 21:56 #7 

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(Site Admin)
Interesting observations. Factory installed battery lasted 11 years on my ZT. Did the standard falling off a cliff act as with most modern cars. As soon as the battery produces less than the optimum voltage the car will not start. However the battery would still be able to start an old vehicle albeit with reduced cranking power. Long live the current (excuse the pun) installed Bosch battery.

Posted 23 Apr 2018, 09:47 #8 

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Got a cheapy Lion Batt on wifeys Zr . only about 1 years into a 3yr warranty, went flat for no reason ?

had it tested at my local garage, seems it was not very good under load.. took it back to ECP who tested it again with a different device and their result was 64% efficiency, and would not change it as it has to under 60% .
To be fair its been alright ever since, but keeping an eye on it ..
Got one for Me , Then one for her, and now a big one for me again, All BLOO! Well saves on the touch up paint, Now Number one son's Spoilt it all by getting a Firefrost 1.8T

Posted 03 May 2018, 09:22 #9 

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Well at least you still have warranty for another 2 years, Steve had a battery from ECP which was under warranty and going flat if unused for a few days , we went down the route of looking for what may be drawing from the battery before we took it back to ECP when it tested fine ( not unsure of % ) , they were reluctant to change it but in the end did and the replacement was fine with no starting issues if left for a few days.

I had one from another company with similar issues the first battery tester they used said it was fine but I was insistent so they used a different tester which said it was faulty so it was changed and all ok again
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Posted 09 May 2018, 18:33 #10 

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Bermudan 75
Faulty testers nearly caused my cateract surgery be postponed. One blood pressure machine said my blood pressure was to high to proceed with the procedure. Another machine was then used and everything was OK.

Posted 09 May 2018, 18:46 #11