New battery and alternator = no luck

[blueray95]

Hi,
I've holden caprice ss 2009 and the issue started 4 months ago I got the battery saving mode on the dash and it was loose ground cable to I've tighten it up but 3 months later I got same problem but the ground wasn't loose and I've replaced the battery and the alternator 3 times one of them is new but no luck. checked the ground was fine also engine belt is new and fine. the volt according to the engineering mode is around 12.6v and I have to rev the car to 2000 rpm so it can charge and it read around 13.5v but when i stop driving for few minutes the volt is again 12.5v any ideas?

 

[rambunctious]

Clean up the earths/connections before refitting them.

 

[MYVESSV8]

what alternator did you put in, heard a few stories that one or two of the aftermarket wont charge correctly, something to do with rpm etc designed for stationary engines
new battery and alternator should be about 12.5v, when running maybe 12.9v, loaded up lights a/c etc 13.5v or more, battery condition, load, connections all play a part in this, use a multimeter to check your volts etc more accurate, you can get battery load tested(to confirm condition)and check your charging rate also while your at it (use multimeter)

 

[pnlimo]

Is the new alternator a genuine GM one for the Caprice? The correct alternator charging is controlled by the BCM. Some aftermarket ones are not designed to do this. The output of my Caprice's alternator varies between 13.2 and 15.1V depending on electrical load. Also, the higher voltage output occasionally observed is, I understand, required to maintain the calcium battery's condition.

 

[blueray95]

Clean up the earths/connections before refitting them.

I've checked the earth cable by multimeter and it was good and clean

 

[blueray95]

what alternator did you put in, heard a few stories that one or two of the aftermarket wont charge correctly, something to do with rpm etc designed for stationary engines
new battery and alternator should be about 12.5v, when running maybe 12.9v, loaded up lights a/c etc 13.5v or more, battery condition, load, connections all play a part in this, use a multimeter to check your volts etc more accurate, you can get battery load tested(to confirm condition)and check your charging rate also while your at it (use multimeter)

I bought this one (OEM) https://www.amazon.com/gp/product/B005OVFEMY/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1
and I did check using multimeter but still it was low. and if the voltage was around 13.5v and shut all accessories it would still be the same and if it was 12.5v and ran all the accessories it just will jet low as 11.8v something like that. I am started to think it might be the regulator if it have one?

 

[blueray95]

Is the new alternator a genuine GM one for the Caprice? The correct alternator charging is controlled by the BCM. Some aftermarket ones are not designed to do this. The output of my Caprice's alternator varies between 13.2 and 15.1V depending on electrical load. Also, the higher voltage output occasionally observed is, I understand, required to maintain the calcium battery's condition.

15.1v I never saw that on mine! I got this alternator same as the original oem https://www.amazon.com/gp/product/B005OVFEMY/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1 and btw mine doesnt seem to respond to any electrical load, I mean if the voltage already was lets sat 12.5v it just will get lower to like 11.8v!

 

[pnlimo]

Where are you taking the voltage measurement from? Mine is read direct from the OBD and the fluctuations are quite noticeable depending on electrical load and how long the vehicle has been standing. I have been informed by an auto electrician that this is normal.

 

[blueray95]

Where are you taking the voltage measurement from? Mine is read direct from the OBD and the fluctuations are quite noticeable depending on electrical load and how long the vehicle has been standing. I have been informed by an auto electrician that this is normal.

I get the reading from the engineering mode from the dash but I did use multimeter to check. you sure thats normal? cause I can see that the battery charge getting lower and lower :/

 

[syked]

I bought this one (OEM) https://www.amazon.com/gp/product/B005OVFEMY/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1/QUOTE]

How many amps output does this alternator produce. Should be on the sticker but can't see it on the photos /description on Amazon .