Thread: D2 2004 Auto TD5 - Voltage conundrum

12.5 at rest sounds a bit low to me for a new battery. Try charging it overnight, and see if the numbers improve.

Sounds like alternator to me recently replaced one doing the same thing

Hi ahw, and a battery ( new or old ) at 12.5v is GOOD, but how long after you turned the motor off did you measure the voltage.


You need to check the voltage at the battery terminal, not at any in-cab device, when you have been for a drive of at least 30 minutes.


You need to drive for at least 30 minutes so the voltage is at the lower normal operating voltage and leave the motor running. Then turn everything off and measure the voltage at the cranking battery with the motor idling. This should be around 13.5v.


If so then your alternator is most likely not a problem.


Start there and see what you get.


Again, ignore in-cab voltage readings. They are just not reliable.

Originally Posted by ahw3617

..... When roadside dude installed the new battery he needed to undo a holding clamp to release more of the 'negative cable' to reach the terminal... dunno if relevant but thats possibly useful to know.

Anyone been here before?

Dunno about red herring.
Holding clamp?
Just behind the battery is a section of the earth lead that is earthed at the body, then continues further down and is then bolted to the engine block.

Did he undo the nut on the body and release the cable from there?

Originally Posted by ahw3617

Hi all,

I think I have a problem though confused at same time. Recently installed battery (factory) into 2004 D2 TD5 Auto after last one died. At idle voltage across terminals is 13.6 though Hawkeye diagnostic (connected via OD showing 'live data' reading of 11.6. When I load more accessories this reading will goes into the 10s... No battery warning light though. If not for the '3 chimes' and the duller than usual dash lights I would not be alerted to anything that looks problematic. When vehicle turned off the batter voltage shows 12.5 across the terminal with Hawkeye showing 12.2.

This may be a red herring though coincides with the issue I think. The new battery is centre posted versus prior one where posts where closer to the rear edge of the battery. When roadside dude installed the new battery he needed to undo a holding clamp to release more of the 'negative cable' to reach the terminal... dunno if relevant but thats possibly useful to know.

Anyone been here before?

\
IMO the alternator is FUBAR though make sure that maxi fusible link FL1 is not blown

Hi all, thanks for your input; I did charge the battery and while the voltage across terminals indicate a basically healthy battery, when running, the alternator was only pushing out about 13.2 volts without much load.. AutoElec prognosis was a subtle fault with the alternator - not charging enough - though enough to keep the warning light away. Max fan and AC (its been hot in Brissie lately) plus spotties and sub-woofer would get the chimes ringing at idle - which (I'm guessing) was a warning the charge was less than the current drain. Anyway a rebuild on the way - hopefully that'll be it. Good to get this sorted (200K on the clock) before I take it and the better half for 12 months getting lost next year

I reckon there are alt part ( bearings etc) numbers in the TGO
just in case,,,

The 'holding clamp' is the main body earth.. do not continue to drive the vehicle like this as other components are now taking on the task of earthing. What a turkey😣 fancy undoing a main earth strap to fit an incorrect battery...some of these RAC types are I'm sure are rather dim...
And i would advise a new alternator as there are components in them that are not replaceable.

Jc