Strange Peugeot Partner electrical problem

[oldwheels]

I replaced my car battery recently when the engine failed to turn over and I cannot get any clues to a problem. Alternator is charging normally according to the AA guy.
A battery symbol light was flashing when ignition on but goes out when engine starts. New battery and light is steady when ignition is on but if engine not run for a couple of days the light starts flashing again tho' there is enough power to start ok. It suggests a current leakage somewhere when ignition is off. Anybody had this problem and where did you look?
My local garage [the only garage] is severely short staffed so getting any assistance anytime soon is not likely.

 

[DCLane]

If it's anything like ours I would suggest ignore it. It frequently does that and there was never an issue in the 5 years we've had the car.

It seems that if you've the alarm it drains a bit of the battery and the sensor gets scared.

 

[sleuthey]

Do the basics. Disconnect the battery overnight (clears any fault codes in ecu). While it’s disconnected charge it (helps rule out alternator). Before reconnecting clean the contacts with wet n dry paper and make sure they are tight.

 

[bikingdad90]

Radio amp not turning off causing a flat battery?

 

[fossyant]

See if there is any buzzing or warmth in the alternator when the engine has been off a few hours ? Could be a parasitic drain from a faulty alternator - our Aygo has just done the same - they basically turn into a 'motor' but can't move due to the belt when they go faulty. Ours was still charging.

Tried a new battery, dead overnight, Tested the battery after a charge, and could see it dropping voltage more quickly than it should. Poking about I could hear a very faint buzz - nothing should be on. Pulled out various connectors, still there, then noticed the alternator was warm.

Faulty diodes basically or voltage regulator, causing power to flow back to the alternator. A new one fixed it.