Technical Alternator or charging woes

[zippeyrude]

I noticed a nearly flat battery a couple of days ago.

Plugging in odb and Torque app, the charge showed 13.6v with revs, which seems low.

Are all panda alternators the same?

The possible failing car has aircon, whereas I have access to a non aircon donor car. Are the alternators the same?

 

[zippeyrude]

I noticed a nearly flat battery a couple of days ago.

Plugging in odb and Torque app, the charge showed 13.6v with revs, which seems low.

Are all panda alternators the same?

The possible failing car has aircon, whereas I have access to a non aircon donor car. Are the alternators the same?

Looks like aircon and non aircon are different

5530A14 ALTERNATOR - R+R FOR VERSIONS WITH AIR CONDITIONER - Fiat - PANDA - eLearn - 4CarData

Any other tips before I attempt to swap out the alternator, for example any common wiring issues. Etc?

 

[dagdromer]

13.6 is fine for charging I don't think the alternator is the problem. I think you should look for applications that drain the battery while the car is off. Look into the glovebox, boot for interior lights, an 12v usb charger, radio or obd2 connector that stays active.

 

[Otterjack]

If the alternator does not charge, the battery light in the dashboard should light up. Other than that, the power assisted steering would be atuomatically deactivated to save battery life, as in case of emergency this strategy gives you extra engine running time before the battery dies.
To check alternator functionality you can test the voltage with engine off and then while revving; 13.6V is a little bit low but if it is charging you should not experience problems.

Before changing the alternator I would check for parasitic drains as Dagdromer told you, then you could try another battery, just in case the actual one got some damage and increased internal resistance from discharging or plain age (how old is it ?).

 

[koalar]

The battery light on the dash is controlled by the body computer

It checks the D+ wire at ignition on pulled down to below 4.5V

It then checked the voltage is over 5V with the engine running

You can't measure the battery voltage accurately with software

13.6V = 14.1V

All my cars have been 14.2V so close enough with a digital multimeter across the battery terminals

All my cars measure roughly 0.5V below when measured with software, some software allows you to compensate for the error

The fiat part number is on the alternators label, there's several fitted year, model, engine

 

[zippeyrude]

Thanks for the steer, I checked with multimeter and it's pushing out 14.05 on idle, with 13.95 on idle and full load ( full lights, both fogs,rear demister). So thankfully it doesn't look like the alternator.

Oddly it has started fine the last two days...

 

[koalar]

How old is the battery ?

Using the Torque app, graph the battery voltage as you crank the engine

It will dip right down at the begining , almost a dead short until the starter starts to turn

Then bounce back as it starts to crank


Here's mine, with a fairly duff battery,

Almost does not start

Remember the true values in this graph are roughly 0.5V higher

The bottom trough needs to stay above 6.5V otherwise the body computer resets,


The ECU need 5V for it's sensors plus a little headway


The little flat bit as it cranking at just under 10V should be around a volt or more higher

This battery just about made it through a winter, as long as the car was used daily, and you didn't mess around, straight in, crank the car, I would fail if left a few day