307SW 2007 2.0 HDi draining the battery

[ozfrog]

I admit it - I don't know where to start looking.

If the battery is not connected, it will retain almost full charge for a few weeks.

However, if I connect the battery and don't drive the car, the battery will be drained within 4 days. If I drive the car, it is even worse! The battery will probably be drained the same day. But that will depend on how much I drive the car.

I'm almost certain that the battery isn't being charged when I'm driving (or just running the engine). But I think the real problem is that the battery is being drained when the car is just sitting and connected to the battery. I've killed one battery completely, and I thought I'd killed a second, but somehow it managed to recharge; I still don't know why.

Any pointers gladly received!

[myglaren]

My suspicions would fall on the alternator following your description of the symptoms.

[ozfrog]

Even when the car is just sitting, doing nothing?

[mickthemaverick]

Even when the car is doing nothing the alternator charging circuit is still possibly connected to the battery and if one of the diodes in the rectifier has failed, gone short circuit, it could result in putting a load on the battery.

[ozfrog]

… the alternator charging circuit is still possibly connected to the battery

Possibly connected to the battery!
So how do I determine if it is, not just possibly?

… and if one of the diodes in the rectifier has failed, gone short circuit, it could result in putting a load on the battery.

There are a lot of 'ifs' and 'possiblys'! Oh, and 'coulds'. How do I eliminate those 'possiblys' and 'ifs', and 'coulds'? In other words, where do I begin testing?

At least, that's what I think I should be asking …

[wurlycorner]

So how do I determine if it is, not just possibly?

You need to do a parasitic drain test.

Open all doors, boot, bonnet and covers to fuse boxes.
Manually trip over all the door locks and bonnet/boot locks to 'closed' with a screwdriver.
Cover over the alarm ultrasonic sensors with tape (insulating tape works fine).
Tape closed any over switches that detect door/bonnet/boot being open.
Lock the car on the key fob and leave it for about half an hour so that everything should go to sleep.

If you have a clamp-on current meter that can measure current from DC (most only do AC) then you can put that around the battery positive or negative lead and get an overall current draw - it should be very very low. Alternatively if you have meter than can be used in series to measure current, you can (earlier, before locking the car) connect that between the negative terminal on the battery and the negative lead.

Then use a multimeter to measure voltage across every fuse (touch the exposed terminals on both sides of each fuse) and record it on a sheet, along with the type of fuse (mini/normal/maxi) the fuse number and current rating. What you measure will be nothing, or in millivolts.
Whichever circuit/s are showing a voltage in that test, have not gone to 'sleep' and are still using current, draining the battery. A couple of circuits may still show under normal conditions (but be very very low current draw) but most should not be using anything and the faulty one would be obvious - higher than any others.

You can find conversion charts online that will tell you by fuse rating and measured volt drop, how much current that means the circuit is using.
e.g. https://caravanchronicles.com/wp-conten ... -table.pdf

That way you can find out which circuit is draining your battery and then you need to investigate on that circuit to find out what has failed.

Note: that likely wouldn't cover the alternator itself - because that often doesn't have a fused connection to the battery but direct connection (I don't know the set up on the 307?).
You can check that with a clamp on current meter on the main lead between the battery and the alternator.


If that doesn't make sense then here's lots of videos on line showing how to do this, but I'm gonna give a link to one by the main man, Eric O.

[mickthemaverick]

The 'possibly' is because some vehicles have a cut out in the circuit operated by the ignition and some don't. Test the alternator main contact for the charging lead and see if it has 12V with everything off. If it does then you have no cut out. Then disconnect the lead from the alternator and connect it back via your multimeter on the 20A scale and see if the current is going to the alternator. If it is there's your problem. If not back to eliminating fuse circuits one by one until you find the stray current.

[PaulC5]

Are there any aftermarket accessories on the car such as a tow bar, dash cam, sat nav, phone charger - if so disconnect them to see if they are giving a constant battery drain.

To check if the alternator is working, a quick way is to measure the battery voltage with the engine off and the engine running. Engine off before the first start of the day the battery fully charged will be around 12.7 volts, engine running about 14 volts if the alternator is working. You should check the alternator drive belt is in good condition and not slipping.

[ozfrog]

Are there any aftermarket accessories on the car, such as a tow bar, dash cam, sat nav, phone charger - if so, disconnect them to see if they are giving a constant battery drain.

There is a tow bar, but as far as I can tell, it was a 'factory fitted" one. Best Bars New Zealand seems to have had a contract or other arrangement with Peugeot Australia to supply and fit tow bars around the time.

The wiring was rather odd, for Australia, at least. It had a 13-pin round plug. When I bought the car and wanted to use my 'box' trailer with the car, I couldn't find any converter plugs to go from the standard Australian 7-pin flat plug to a 13-pin round. I had to figure out which pins were going to be used from the car side and then wire up a new 7-pin flat Australian-style plug. Then I had to terminate and block off the remaining pins to ensure that nothing would short out. And in case you're wondering, this method has been working successfully with no electrical issues for the past 5 years. I'm sure that the issue I'm currently facing is not linked to the rewiring of my tow bar wiring plug.

For those interested, I've included a diagram of the more common and some uncommon trailer plug systems used in Australia. I have never seen a 4-pin wiring system, and only once, I think, a 5-pin wiring system.

And a 13-pin round wiring diagram.

[ozfrog]

You need to do a parasitic drain test.

I thought you were joking when you used that term. Or maybe having a lend or me!

Open all doors, boot, bonnet and covers to fuse boxes.
Manually trip over all the door locks and bonnet/boot locks to 'closed' with a screwdriver.
Cover over the alarm ultrasonic sensors with tape (insulating tape works fine).
Tape closed any over switches that detect door/bonnet/boot being open.
Lock the car on the key fob and leave it for about half an hour so that everything should go to sleep.

If you have a clamp-on current meter that can measure current from DC (most only do AC) then you can put that around the battery positive or negative lead and get an overall current draw - it should be very very low. Alternatively if you have meter than can be used in series to measure current, you can (earlier, before locking the car) connect that between the negative terminal on the battery and the negative lead.

Then use a multimeter to measure voltage across every fuse (touch the exposed terminals on both sides of each fuse) and record it on a sheet, along with the type of fuse (mini/normal/maxi) the fuse number and current rating. What you measure will be nothing, or in millivolts.
Whichever circuit/s are showing a voltage in that test, have not gone to 'sleep' and are still using current, draining the battery. A couple of circuits may still show under normal conditions (but be very very low current draw) but most should not be using anything and the faulty one would be obvious - higher than any others.

You can find conversion charts online that will tell you by fuse rating and measured volt drop, how much current that means the circuit is using.
e.g. https://caravanchronicles.com/wp-conten ... -table.pdf

That way you can find out which circuit is draining your battery and then you need to investigate on that circuit to find out what has failed.

Note: that likely wouldn't cover the alternator itself - because that often doesn't have a fused connection to the battery but direct connection (I don't know the set up on the 307?).
You can check that with a clamp on current meter on the main lead between the battery and the alternator.


If that doesn't make sense then here's lots of videos on line showing how to do this, but I'm gonna give a link to one by the main man, Eric O.

It looks complicated! I will hopefully get to it on the weekend - when I can enlist the help of some more experienced Peugeot friends.

[ozfrog]

The 'possibly' is because some vehicles have a cut out in the circuit operated by the ignition and some don't. Test the alternator main contact for the charging lead and see if it has 12V with everything off. If it does then you have no cut out. Then disconnect the lead from the alternator and connect it back via your multimeter on the 20A scale and see if the current is going to the alternator. If it is there's your problem. If not back to eliminating fuse circuits one by one until you find the stray current.

Time-consuming?

Just as well we started daylight saving last weekend! Mind you, I'm still convinced that retirement wasn't meant to be this busy.

[wurlycorner]

I thought you were joking when you used that term. Or maybe having a lend or me!

Nope - that's the genuine term for it!

It looks complicated! I will hopefully get to it on the weekend - when I can enlist the help of some more experienced Peugeot friends.

Don't worry, it's pretty simple tbf - just time consuming.
You really don't need to worry about the ammeter at the battery bit if you don't have the right equipment for that. That's just extra help, but just the voltage drop across the fuses will trace it.

Personally I don't remove any fuses until I've tested them all, just in case removing / replacing one causes a 'wake up' on the whole system and that means you have to wait for it to time out again - but that may not be a valid concern (depends on the specific car electronic architecture).

Do check the alternator first though, as others have suggested.

(I really must get round to writing up the results of the parasitic drain test I did on my x7 earlier this year and ask for the relevant schematic so I can trace the fault on that circuit!)

[PaulC5]

To eliminate the tow bar I would remove its fuse(s) in case its wiring has become damaged or damp/dirt in the socket are causing a short to earth. I used to remove the fuses on our C5 when not being used since the bypass relays used a bit of current, not a lot but helped to gradually discharge the battery over time.