Unusual battery drain

[SNC]

It's unusual to me anyway.

I have a 2014 mk4 2.0 163bhp diesel mondeo with 130k miles on the clock has always been a little hesitant to cold start (a second longer than you would hope usually).

However I didn't use it for 2 days over new year, come the 2nd of Jan and the car wouldn't start, dead battery. The battery was replaced with a new one during it's service a month ago as the battery was draining with irregular wattages/volts.

So ordered a trickle charger, disconnected my dashcams after every drive (even though they turn themselves off when the engine stops).

While waiting for the trick to arrive I've been looking on the forums to see what could be drawing power over night. Saw it mentioned that there's a common issue with the usb not powering down without a software update from ford, so just took the music USB out for now and made sure the cars entertainment screen is powered off when I'm not using the car. 

Plugged the trickle in for the first time yesterday at about 2pm.It said it was under 80% and fast charged for about 2 hours then went to reduced charge for another 6 hours before completing 100% charge and tests at 10pm, took it off and went to sleep. 

Reconnected trickle at 9am next day and battery had dropped below 80% and it's took nearly 2 hours to get back to over 80% again so it's basically draining about 40-50% battery in less than 12 hours and everything I can is turned off or unplugged.

Starting to think the alternator is consistently draining power which is what a Halford mechanic has said has been the case on a couple of Mondeos and Focus' but does anyone else have any other advice of what it could be?

 

Cheers

[Westville]

Parasitic battery Drain - is an absolute pain in the a@*se to rectify

You will need to try and ignore what you think may be causing it and test everything to find out what really is doing it

This video may help you as it clearly shows what you need to do

https://www.youtube.com/watch?v=YhC8xj5vHUg

Good Luck 

[isetta]

how easy is it to get to the alternator connectors?  could you easily disconnect all alternator wires for one night and then check to see.

The rectifier built into the alternator turns ac current to dc. But, being made up of some diodes it also performs the important function of a valve which only lets current pass one way - out of the alternator and not back into it. If a diode is failing, current can leak from the battery back into the alternator.

I have had a car that did this - many years ago.

 

[SNC]

Sorry I had to go out after typing the query so thanks for the replies, I will have to get a multimeter (or two as that video suggests). I don't know enough about cars to know anything about the alternator except what it looks like lol

I think the alternator parts if it's that will have to be tested and sorted at a garage.

[Luke4efc]

You don't need 2 multimeters. Just connect one in series and set it to amps (as the video suggests). If you're getting any current showing the start pulling fuses one by one and see which one makes the current draw stop.

[SNC]

Sorry, it seemed to suggest in the video not to pull fuses to stop electric systems that should be running from causing issues and instead check  the back of each fuse with a second multimeter. So I thought that was an advisory.

[morrismen]

I had this weird problem with my prior '57 Diesel TDCI Mondeo. When it was standing switched off, about every 30 seconds or so I could hear this "tick-tick" from the engine bay which I thought was something to do with the Alarm system - never did find out what it was though. I am sure it was this that used to drain the battery after about 3 days, but luckily there was some sort of in-line capacitor system which allowed the car to still start, even with the battery being flat which was really neat. With the short journey's I did, the battery was never really getting charged properly. in the end, I had to get a Ceramic Type Battery which kept the charge much better.