I started the car this morning and the battery light stayed on so I turned it off turned it back on and it went off.

I'm currently hunting my multi meter so I can see what state the battery is in. What kind of voltage should I get with cat off and no load and also at idle with load ? I ask only be as usr I know the smart charge system can give different figures than a non smart charge system ?

Throughout the day the light has not returned but I think it warrants a poke around.

I'm guess either a blip or something potentialy going wrong in the charging system.

what do you think ?

likely a faulty battery cell at idle with no load from cold 14.4 v with rear heated window and lights it should drop slightly a rev to 2000rpm should see it go up to 14.4v you should get over 13.5v with rear window lights fogs on but not with the front window switched on just to see how much juice that uses pop it on and watch the figures drop like susan boyle in a cake shop lol

Looking at the battery it looks original and has motocraft written on it, bearing in mind it an 04 might be wise to pick up a new one.

I found my multi meter here's my

findings:

12.47v with engine off.

14.40v idling

14.18v idling with dipped beam on and heater on 4.

11.62v with above on plus heated front and rear windows, hell of a draw they take.

lol @ Susan Boyle joke.

Battery seems ok to me, if you could attach the multi metre to the battery and route it inside the car, you could see the smart charge system working,,, drive along and load up the electrics, and were you are seeing 11v with the front and rear screens at idle, this would jump back up past 14v if its all working correctly.

Those readings are fine exactly as they should so the battery and alternator seem to be fine may have been a glitch keep an eye on it and see how it goes

Yeah starting to look like a glitch, odd one. Been fine ever since. I'll report back if it does it again. I am tempted to get a new battery but as this still seems fine I will leave it alone.

I got one of those feeble looking jump starting devices for Christmas, I know jump starting a focus is bad as the smart charge voltage can spike and damage electrical bits. I'm thinking worst case scenario if I disconnect the smart charge system, which I think is that 3 pin plug on the alternator can I jump start it then safely ? Purely hypothetically speaking, I'm just curious if there is a safe way to jump a focus.

fords stance is its at the owners risk