Member Since: 29 Jan 2012
Location: Staffordshire
Posts: 506
Complete electrical failure
Hey dudes, it's been a while. Hope everyone is happy and healthy.
Quick scenario:
I changed my 5 year old battery as during the cold weather 2 weeks ago the lights in the cabin would come on but the engine wouldn't crank.
So, new battery in. Have used the vehicle, as in, cranked the vehicle about 6 times with the new battery.
Went to the car yesterday and the key won't unlock the vehicle, no signs of life in the cabin. Proper dead.
I manually opened the car door - no alarm. Super dead.
Attached cables from wife's civic to the dead battery lots of sparks from the negative terminal and the cables got hot after a couple mins. Lights in the cabin did come on but starter motor clicked a couple times but didn't crank the engine.
Is it as simple as the alternator is kn@ckered and has therefore kn@ckered the new battery and I need to replace both?
Could it be a fuse issue or something else I could look at, please?
I'd start with checking negative connection to battery is on properly.
20th Dec 2023 11:31 am
Kilovolt
Member Since: 29 Jun 2015
Location: South Derbyshire
Posts: 1020
And the body earth strap, could be a coincidence failure "Track day running - Don't put your foot back on the accelerator until your absolutely sure you don't have to take it off again"
Current Ride: D4 XS Commercial Baltic Blue SDV6 fully loaded with heated everything
Track Days: BMW E36 M3 Evolution MY 1996 (3.2 Litre 377 BHP sat in 1,250 Kgs of car, with a pro safety cage and some serious braking power)
20th Dec 2023 12:02 pm
Lumberjackwhite
Member Since: 29 Jan 2012
Location: Staffordshire
Posts: 506
Sparks would be at the point where circuit is breaking/making, hence my suggestion..
Dean
====================================
2011 D4 XS - OBD port protection, RLD spare wheel protector, All LED interiors lights, Timed Climate enabled, iiD tool paired.
2011 D4 Landmark - Stolen from same dealer before I paid for it
2011 D4 GS - Stolen whilst at dealer ... All LED interiors lights, DRLs, Spare Wheel protector.
1996 300Tdi - Eaten by tin worms
20th Dec 2023 12:31 pm
Lumberjackwhite
Member Since: 29 Jan 2012
Location: Staffordshire
Posts: 506
Thanks chaps. I can look at the negative cable in more detail. It's stuck on tight to the battery terminal so I'm sure the connection is there.
Will check to see if it's not connected to the body of the vehicle.
Let's say the negative is NOT connected to the body, could that cause a catastrophic draw of power from the battery to make it so flat?
if the battery negative isn't connected to "earth" - be that engine or body (probably both for a Disco) - then it might as well not be in the vehicle.
Could be fully charged or could be flat. put a multimeter across the terminals and you should get 12v, give or take.
If it's not nearly that, test the volts between battery negative and body/engine. If that's not zero, then your connection isn't good.
there's someone on FB who had same issue recently and it was the connection on battery -ve that was bad.
alternatively, the "just rolled in" end-of-year compilations incluse someone with same complaint who hadn't removed the protective cover off the -ve terminal.
20th Dec 2023 2:12 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4658
Lumberjackwhite wrote:
Could that be why it's sparking so much?
You might have a dead short (ie positive to earth!!) If this were so, the likely culprit is the starter positive cable where it runs across the front diff and around the sump to the starter. Over time, the cable sheath can wear against the diff housing until it eventually shorts the live battery cable on the diff. It's not that common but it does happen!
Click image to enlarge
Click image to enlarge
As per the second pic, the cable can be covered with heavy sheathing and strapped to the steering rack.yµ (idµ - eAµ) ψ=mψ
20th Dec 2023 3:18 pm
Lumberjackwhite
Member Since: 29 Jan 2012
Location: Staffordshire
Posts: 506
Hey guys,
Happy new year and thank you for the advice a couple of weeks ago. Due to a chest infection the car scenario has stayed on the backburner until today.
So, I managed to get a replacement battery from Euro Car Parts and have turned the vehicle over with the battery installed and it started with no issues - I immediately removed the battery after we got a multimeter on it.
We checked the volts of the battery before installation - 12.8V
We checked the the volts of the battery while installed and not turned on - 11.8V - obvious drain
We checked the volts of the battery while installed and the car running - 4.0V
To sense-check, I'm thinking the alternator is knackered anyway so will replace in the next few days.
Given those above readings, could there be any other places I could look / test?
Thanks again all
5th Jan 2024 3:52 pm
HairyFool
Member Since: 04 Jan 2023
Location: Essex
Posts: 526
4v on a battery, engine running or not is a seriously damaged battery as it should be considerably higher than that even when cranking the engine. If the battery was fully charged when tested off load to draw enough current to take it down to 4v I would expect to find something smoking as we are talking several 100A.
I would recharge the battery and then measure the current drain through the negative lead without turning anything on, doors closed and the bonnet catch set closed. The main problem with that is most multimeters are limited to 10A even when using the dedicated terminal, if there is a big issue the fuse may blow.A visitor from the dark side, my other vehicle is an MG5 EV
5th Jan 2024 8:31 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4658
Dead short, see my earlier post. Tread carefully you have a very real fire risk!yµ (idµ - eAµ) ψ=mψ
5th Jan 2024 8:39 pm
Lumberjackwhite
Member Since: 29 Jan 2012
Location: Staffordshire
Posts: 506
Hi Hairy,
The battery is brand new and a replacement of the one I originally had from Euro that I bought 4 weeks ago. Due to me exchanging the battery, Euro checked the new battery over to ensure it was fine.
So I'm led to believe there is something heavily pulling power from the battery when the car is both on and off.
But, being honest, I have limited experience with electrics so happy to take other people's steer. Just wanted to add further context.
5th Jan 2024 8:41 pm
Lumberjackwhite
Member Since: 29 Jan 2012
Location: Staffordshire
Posts: 506
PROFSR G wrote:
Dead short, see my earlier post. Tread carefully you have a very real fire risk!
Hi Profsr, think we crossed over there!
Thanks for the above pictures and comment. How easy / difficult is it to access this wire? The car is sat on my drive right now.
5th Jan 2024 8:44 pm
Lumberjackwhite
Member Since: 29 Jan 2012
Location: Staffordshire
Posts: 506
Just to add something in case it's relevant:
I've not been able to use the heated seats in the car for about 3 years now as it gets incredibly hot and literally burns my backside through the seat.
Could this be related in any way?
5th Jan 2024 8:52 pm
HairyFool
Member Since: 04 Jan 2023
Location: Essex
Posts: 526
As said, this sort of current with any ordinary cable would turn to smoke. The fact that you have been able to turn off the seats would indicate some sort of control is working. A battery drop tester (rarely used now) would turn cherry red with the power going through it so I would have to agree something close to a dead short across the battery and unfused so carefully follow the battery positive lead everywhere, not easy but if there is a section you can't see because it is covered then that is even more important to look at.A visitor from the dark side, my other vehicle is an MG5 EV
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... All LED interiors lights, DRLs, Spare Wheel protector.
