Peugeot 308 alternator not charging?

[wheeler]

There are also inconsistencies because on the charging diagram it shows an ECU with a single 55 way connector but this car has an ECU with 28 way connectors.

In this part of the Circuit only the 53v NR connector on the ECU is used, The diagrams will normally only show involved connectors. In this case it will just be that none of the connections on this system are connected to the other ECU connectors so they are just not shown.

I wonder if the battery monitoring system is faulty & making the car think the battery is fully charged?

Does it start charging properly again if you switch on heavy electrical loads like heaters & heated rear screen?

[xantia_v6]

The alternator always produces enough amps to exactly balance the load, it is just that the smart charging system is not setting the voltage target high enough.

I have read that smart charging systems similar to this, deliberately stop charging the battery when it reaches 70% or 80% of capacity, so that the alternator can harvest free energy during engine braking. I have checked that during engine braking down hill this car is not charging the battery.

Today I fitted a new battery of the correct din55L type, just in case.the old battery had some kind of degradation, but I don't see any immediate change of behaviour. Can anyone confirm that there is no need to tell any ECU that a new battery has been fitted?

[Huskyxantia]

Ecu should know a new battery has been fitted , but saying that knowing these cars plug it in check for parts and see if theres any mention of batterys.

Sorry if i sound dumb but ...



Have you done an amp test with the ignition off discomnect the negitive lead then connect the tester to the neg post of the batter then clip the live tester lead to the lead that was taken off its neg terminal ? has the car had any stereo changes at all ? Leave the meter connect up as is , then take the live wire off the alternator see what the amp reading is , id say if the numbers drop then the alternator could be coming to the end of its sercice life. Check amp before the alternator lead comes off and after.

If you have accept my apologies

[GiveMeABreak]

I have read that smart charging systems similar to this, deliberately stop charging the battery when it reaches 70% or 80% of capacity, so that the alternator can harvest free energy during engine braking. I have checked that during engine braking down hill this car is not charging the battery.

That's only for stop start systems as far as I know (those with energy accumulator and central voltage retaining ECU, but am not 100% on this.

[xantia_v6]

The only quantitative data I have found is in this post https://www.peugeotforums.com/threads/n ... st-2306779 , but it is not clear whether it relates to stop/start or normal smart alternators.

I have checked my car, and switching on the headlights does not change the voltage, but I have never seen it go above 14.5V (and that is only after reconnecting the battery)

Since fitting the new battery, the charging voltage seems to have stabilised around 13.2V, which may be normal, we shall see.

[xantia_v6]

Another update...
Since changing the battery the car has no been driven much, but on the initial trip the voltage sagged to about 23.2V, and on the next couple of short runs it hovered at about 13.5V.
A day later on a slightly longer run it started at 13.6V and during the run rose to 13.75V where it stayed for about 10km before easing back to 13.5V.

This seems to be more normal behaviour and may indicate that the real problem was always with the charging system not liking the old battery, even though it had ample cranking amps and reasonable capacity.

It would be nice if the system threw an error code to indicate that "The battery is flat but I refuse to charge it."

On the plus side, I am fairly confident that the software upgrade has improved the throttle response and eliminated a bit of a flat spot.

[GiveMeABreak]

How old was the battery? I change mine about every 5 years normally, regardless.

However, I'm on my second already in 4 years (1 replaced under warranty) due to Stop Start not working (and it's not working again now). Understandable as it can sit for a week without being started, so the inevitable slow drain from everything like the alarm and the hands free receivers will keep it under the 80+% it needs for SS to work.

[xantia_v6]

The old battery is exactly 3 years old, on reflection, the battery before that was replaced due to similar symptoms.

[CitroJim]

Pleased this has been resolved Mike.. Amazing what games a slightly unhappy battery can cause...

Do you think the long periods of disuse it has when you're on the other side of the globe make a difference to its life expectancy?

Do you do anything specific with it during these times?

[xantia_v6]

When we are away I disconnect the battery from the car and connect it to a small solar charger which has a nominal charging current of 2A, but I have never seen it produce more than about 300mA, and where it is sited it only sees an hour or so of sun in winter. I figure that it is enough to keep the battery charged without risk of overcharge. I could buy a battery conditioning charger, but have been wary of leaving it unattended for months.

[CitroJim]

That should be fine for keeping the battery healthy and happy Mike...

I too would be wary of leaving any smart charger unattended for months.

[Huskyxantia]

I know a worn tensioner will stop the battery charging properly , i once put the tester on the battery then pushed the tensioner down , the numbers went up on the volt meter, swapped the tensioner with a new one , all was good , think it was a xantia mk2 different car from yours but similair issue with low volt readings.