Year of Manufacture *: 2007 ( Optional ) Engine Code or CC: FUJB
Here is a capture taken from a 2007 Fiesta 1.2 16 valve petrol.
Some of the details are written in the capture, but essentially we are looking at battery voltage taken from key off, then engine start - then steadily applying all electrical loads.
Does not look correct to me.Charging voltage should not drop to 12 volts.What voltage does it show on a digimeter,and what happens if you disconnect the 3 pin smart charge plug?
If it was me Id be concerned at the voltage dropping to below 12v (11.95v) not what most would expect I think. Were the loads removed at the sharp drop or is this the systems response?
Interesting Capture, I don't think you could condemn this on voltage alone...
Applying the loads at Idle may also give you a false reading, I would like to see the load applied (using a Carbon Pile tester) and monitoring the current output at around 1500- 2000rpm and then at idle....
Also what does the voltage do with the three pin plug disconnect?
Interesting to see you got 2 channels missing... I would like to know what you are monitoring on channel C, or would that give the game away???
In this instance is it possible that a component is dragging to much current when applied and the alternator is not coping...??
Thanks for sharing this sounds like it going to be the unexpected.......
OK so I didn't do a very good job of posting that last night, as it wasn't clear that it was a kind of quizzing post & not a seek for help post.
The reason for the in depth look at this was because the car came in with a reported breakdown due to a flat battery at motorway speed, where the RAC came out & put some jump leads on, to start the car & during the journey home it repeatedly cut out & had to have another brief charge to get her going again.
Since then it had travelled over a hundred miles back to Coalville, so that I could take a look at it. All basic tests that I performed, showed that the charge system & battery were good. There were "under & over" voltage DTC's in many modules though.
I thought it would be interesting to monitor voltage vs current over several minutes, in the hope that something would stand out. I have seen voltages drop quite low before at idle with all consumers turned on, but this case made me question (or maybe over analyse) everything that I was seeing.
I noticed that the battery light would come on after prolonged periods of idle with high electrical loads. I even considered the possibility that the battery might have been on its last legs & not have enough reserve capacity for the task. I duly fitted a loan battery for the purpose of elimination, which made no difference.
Anyway here is the full capture, taken from the car when I managed to witness it misbehave.
I have used both amps clamps (60 & 600 amp) because I wanted to see a more accurate representation of current than the 600 amps clamp will deliver. I used the 600 amp clamp because clearly the expected current flow exceeds the limits of the 60 amp clamp.
on January 18, 2013, 3:10 pm, in reply to "
