Battery Drain Issues

[barnyg]

Hi all,

Hope you’re all well and are having a good start to the year!

I’ve previous had a sudden catastrophic battery drain that I put down to a dodgy new battery. However I have now had a repeat scenario on my previous battery that I put back in (it was fine and has been reliable for some time - I just did a change as a precaution then reverted when I had that issue). I thought I would ask here to see if anyone else has had similar.

Essentially the symptoms are that I get a sudden drop in voltage to below 5v over a very short period. I have tested both batteries and they were running fine at a normal level and then suddenly I would go to the car and no electrics at all, hence no car start.

I can’t say for sure but it can’t be more than a couple of days since last use and all was fine then. I do however recently recall the last thing I did was get something out of the boot so maybe a first check is that the boot light could be staying on under some scenarios? Of course I currently have no power and not even a trickle to try and charge it up.

Any help would be much appreciated as this is draining my car to the point it is damaging the battery permanently and not just a case of a slightly low voltage…

Thanks

Barny

 

[colb]

I would check out the positive battery connection in the boot, not sure with your model but on the E85 there is also a pyro battery disconnection gizmo that explodes to disconnect the battery in an accident scenario. These have been known to work loose and cause intermitant power loss as the cable is the main feed to the fuse box in the front of the car. Symptoms you describe would point me in that direction to check first. When the car is running put a meter on the battery and see if the alternator is charging, you should see 14v+ if its working ok.

 

[barnyg]

I’ll definitely have a look and see if there’s one of those on the coupe. I remember the last time this happened I checked when I had a charged battery back in and it was charging during driving so fairly sure all ok with the alternator, that was one of the first things I wanted to eliminate. After months of no repeat this repeat drain seems to have happened with the last action to open and close the boot to get a tool, and I know the boot light off micro switch is in the boot lock so will research that too.

 

[Zforbes]

Had a similar issue with my daughter's fiesta, used a multimeter between the disconnected negative battery terminal and the cable to make the circuit, start pulling fuses to see which one gives the biggest drain. It's a pain in the arse but will point you in the right direction. If you don't understand my explanation just Google parasitic draw test and you'll find loads of YouTube examples.

Once you've identified which fuse then just look up what it operates, saves time trial and error guessing

 

[buzyg]

Could be many things. One of which is the Petrol cap not closing correctly. I know this because that tiny wee bugger killed two of my battaries before my tech tracked it down. The little rubber sting thing was getting in the way.

 

[Billbob10]

I havejust had same problem. It turned out to be the cubby hole in centre light staying on.so it worth checking things like boot light glove box etc.

 

[Smartbear]

Could be many things. One of which is the Petrol cap not closing correctly. I know this because that tiny wee bugger killed two of my battaries before my tech tracked it down. The little rubber sting thing was getting in the way.

How did the petrol cap flatten the battery Buzy? I’ve not heard that before :?
Rob

 

[buzyg]

Could be many things. One of which is the Petrol cap not closing correctly. I know this because that tiny wee bugger killed two of my battaries before my tech tracked it down. The little rubber sting thing was getting in the way.

How did the petrol cap flatten the battery Buzy? I’ve not heard that before :?
Rob

Not sure, never looked into the technicalities. It is what I was told and no more dead batteries since.